/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --black:   #0a0a0a;
  --white:   #fafafa;
  --paper:   #f2f0eb;
  --off:     #ebebea;
  --dim:     #d8d6d1;
  --mid:     #666660;
  --soft:    #2e2c2a;
  --shadow-sm:  0 1px 3px rgba(10,10,10,0.08), 0 1px 2px rgba(10,10,10,0.05);
  --shadow-md:  0 4px 16px rgba(10,10,10,0.10), 0 2px 6px rgba(10,10,10,0.06);
  --shadow-lg:  0 12px 40px rgba(10,10,10,0.13), 0 4px 14px rgba(10,10,10,0.07);
  --shadow-xl:  0 24px 64px rgba(10,10,10,0.17), 0 8px 24px rgba(10,10,10,0.09);
  --font-display: 'JetBrains Mono', 'Courier New', monospace;
  --font-body:    'JetBrains Mono', 'Courier New', monospace;
}

html { scroll-behavior: smooth; }

body {
  background: var(--paper);
  color: var(--black);
  font-family: var(--font-body);
  font-size: 13px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Hide system cursor on all real elements */
html, body, * { cursor: none !important; }

a { color: inherit; text-decoration: none; }

/* ════════════════════════════════════════════════════════════
   CUSTOM CURSOR — all positioning done by JS via style attr
════════════════════════════════════════════════════════════ */
#cur-dot {
  position: fixed;
  width: 10px; height: 10px;
  background: #0a0a0a;
  border-radius: 50%;
  pointer-events: none;
  z-index: 999999;
  margin-left: -5px;
  margin-top: -5px;
  transition: width 0.18s cubic-bezier(0.34,1.56,0.64,1),
              height 0.18s cubic-bezier(0.34,1.56,0.64,1),
              border-radius 0.15s, opacity 0.2s;
}
#cur-ring {
  position: fixed;
  width: 34px; height: 34px;
  border: 1.5px solid rgba(10,10,10,0.45);
  border-radius: 50%;
  pointer-events: none;
  z-index: 999998;
  margin-left: -17px;
  margin-top: -17px;
  transition: width 0.26s cubic-bezier(0.34,1.56,0.64,1),
              height 0.26s cubic-bezier(0.34,1.56,0.64,1),
              border-color 0.2s, opacity 0.2s;
}
body.cur-link #cur-dot  { width: 14px; height: 14px; margin-left: -7px; margin-top: -7px; }
body.cur-link #cur-ring { width: 46px; height: 46px; margin-left: -23px; margin-top: -23px; border-color: rgba(10,10,10,0.65); }
body.cur-text #cur-dot  { width: 2px; height: 18px; border-radius: 1px; margin-left: -1px; margin-top: -9px; }
body.cur-text #cur-ring { opacity: 0; }

/* White cursor on dark example blocks */
body.cur-example #cur-dot  { background: #ffffff; width: 10px; height: 10px; }
body.cur-example #cur-ring { border-color: rgba(255,255,255,0.65); width: 36px; height: 36px; }

/* White cursor on any dark/black background section */
body.cur-dark #cur-dot  { background: #ffffff; width: 10px; height: 10px; }
body.cur-dark #cur-ring { border-color: rgba(255,255,255,0.55); width: 34px; height: 34px; }
body.cur-dark.cur-link #cur-dot  { background: #ffffff; width: 14px; height: 14px; margin-left: -7px; margin-top: -7px; }
body.cur-dark.cur-link #cur-ring { border-color: rgba(255,255,255,0.75); width: 46px; height: 46px; margin-left: -23px; margin-top: -23px; }

/* Black cursor when hovering a light/white button inside a dark section (e.g. "Enter the Vault") */
body.cur-dark.cur-on-light #cur-dot  { background: #0a0a0a; width: 14px; height: 14px; margin-left: -7px; margin-top: -7px; }
body.cur-dark.cur-on-light #cur-ring { border-color: rgba(10,10,10,0.65); width: 46px; height: 46px; margin-left: -23px; margin-top: -23px; }

/* ════════════════════════════════════════════════════════════
   SCROLLBAR
════════════════════════════════════════════════════════════ */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--dim); border-radius: 2px; }
::-webkit-scrollbar-thumb:hover { background: var(--mid); }

/* ════════════════════════════════════════════════════════════
   NAV
════════════════════════════════════════════════════════════ */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  height: 52px;
  display: grid; grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 40px;
  background: rgba(242,240,235,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--dim);
  box-shadow: 0 1px 12px rgba(10,10,10,0.06);
}
.nav-logo {
  font-family: var(--font-display);
  font-size: 13px; font-weight: 800; letter-spacing: 0.08em; color: var(--black);
  justify-self: start;
}
.nav-links { display: flex; justify-self: center; }
.nav-links a {
  padding: 0 20px; height: 52px;
  display: flex; align-items: center;
  font-size: 11px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--mid);
  border-left: 1px solid var(--dim);
  position: relative; overflow: hidden;
  transition: color 0.15s;
}
.nav-links a::after {
  content: '';
  position: absolute; bottom: 0; left: 0; right: 0; height: 2px;
  background: var(--black);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.22s ease;
}
.nav-links a:hover { color: var(--black); }
.nav-links a:hover::after,
.nav-links a.active::after { transform: scaleX(1); }
.nav-links a.active { color: var(--black); }
.nav-links a:last-child { border-right: 1px solid var(--dim); }

/* sol counter — right corner */
.sol-indicator {
  font-size: 10px; letter-spacing: 0.1em; color: var(--mid); text-transform: uppercase;
  justify-self: end;
}
.sol-indicator strong { color: var(--black); }

/* ════════════════════════════════════════════════════════════
   INDEX — TICKER
════════════════════════════════════════════════════════════ */
.hero-ticker {
  border-bottom: 1px solid var(--black);
  padding: 9px 0; overflow: hidden; white-space: nowrap;
  background: var(--black);
}
.ticker-inner {
  display: inline-block;
  animation: ticker 32s linear infinite;
  font-size: 11px; letter-spacing: 0.22em; color: rgba(255,255,255,0.85);
  font-weight: 500;
}
@keyframes ticker { from { transform: translateX(0); } to { transform: translateX(-50%); } }

/* ════════════════════════════════════════════════════════════
   INDEX — HERO  (3-column balanced grid)
════════════════════════════════════════════════════════════ */
.hero { min-height: 100vh; padding-top: 52px; display: flex; flex-direction: column; }

.hero-main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr 240px;
  border-bottom: 1px solid var(--dim);
  min-height: 0;
}

/* ── Shared column base ── */
.hero-col {
  display: flex; flex-direction: column;
  border-right: 1px solid var(--dim);
}
.hero-col:last-child { border-right: none; }

/* ── Col 1: Title column ── */
.hero-col-title {
  padding: 48px 40px;
  justify-content: space-between;
}
.hero-top { margin-bottom: 0; }
.hero-eyebrow {
  font-size: 10px; letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--mid); margin-bottom: 16px;
}
.hero-title {
  font-family: var(--font-display);
  font-size: clamp(64px, 7.5vw, 110px);
  font-weight: 800;
  line-height: 0.92; letter-spacing: -0.04em; color: var(--black);
  text-shadow:
    1px 1px 0 rgba(10,10,10,0.12),
    3px 3px 0 rgba(10,10,10,0.07),
    6px 6px 0 rgba(10,10,10,0.03),
    10px 10px 20px rgba(10,10,10,0.05);
}

/* Inline mini stats below title */
.hero-meta {
  display: flex; gap: 0;
  margin-top: 32px;
  border: 1px solid var(--dim);
}
.hero-meta-row {
  flex: 1; padding: 14px 16px;
  border-right: 1px solid var(--dim);
  display: flex; flex-direction: column; gap: 3px;
}
.hero-meta-row:last-child { border-right: none; }
.hero-meta-num {
  font-family: var(--font-display); font-size: 28px; font-weight: 800;
  letter-spacing: -0.02em; line-height: 1; color: var(--black);
}
.hero-meta-label {
  font-size: 9px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--mid);
}

.hero-bottom {
  display: flex; flex-direction: column; align-items: flex-start;
  gap: 22px; padding-top: 24px;
  flex-shrink: 0;
}
.hero-desc { font-size: 12px; color: var(--soft); line-height: 1.9; }
.hero-btn-wrap { display: block; }

/* ── Col 2: Gauge column ── */
.hero-col-gauge {
  padding: 0;
  justify-content: flex-start;
  overflow-y: auto;
}
.gauge-header {
  padding: 14px 24px;
  border-bottom: 1px solid var(--dim);
  flex-shrink: 0;
}
.gauge-header-label {
  font-size: 9px; letter-spacing: 0.2em; text-transform: uppercase; color: #666;
  font-weight: 600;
}
.gauge-center {
  flex-shrink: 0;
  display: flex; flex-direction: row; align-items: center;
  justify-content: center; gap: 44px; padding: 32px 24px;
  border-bottom: 1px solid var(--dim);
}
.gauge-svg-wrap {
  flex-shrink: 0; width: 240px; height: 240px;
}
.gauge-svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.gauge-track { stroke: var(--dim); stroke-width: 14; }
.gauge-easy   { stroke: #2d7a3a; transition: stroke-dasharray 1.1s cubic-bezier(0.4,0,0.2,1) 0.1s; }
.gauge-medium { stroke: #a05c00; transition: stroke-dasharray 1.1s cubic-bezier(0.4,0,0.2,1) 0.3s; }
.gauge-hard   { stroke: #b91c1c; transition: stroke-dasharray 1.1s cubic-bezier(0.4,0,0.2,1) 0.55s; }
.gauge-num {
  font-family: var(--font-display); font-size: 48px; font-weight: 800;
  fill: var(--black); letter-spacing: -0.03em;
  transform: rotate(90deg); transform-origin: 110px 110px;
}
.gauge-sub {
  font-family: var(--font-body); font-size: 9px; letter-spacing: 0.14em;
  fill: #888; text-transform: uppercase;
  transform: rotate(90deg); transform-origin: 110px 110px;
}

/* Stats beside the ring */
.gauge-stats {
  display: flex; flex-direction: column; gap: 20px; flex-shrink: 0;
}
.gs-row {
  display: flex; align-items: center; gap: 12px; font-size: 15px;
}
.gs-dot { width: 11px; height: 11px; border-radius: 50%; flex-shrink: 0; }
.gs-dot-easy   { background: #2d7a3a; }
.gs-dot-medium { background: #a05c00; }
.gs-dot-hard   { background: #b91c1c; }
.gs-label { color: #333; min-width: 64px; font-size: 15px; }
.gs-count { font-weight: 800; color: var(--black); font-size: 26px; }
.gs-slash { color: #999; font-size: 13px; }

/* Topic table — directly below gauge-center */
.gauge-footer {
  flex-shrink: 0;
  overflow: hidden;
}
.gauge-footer-label {
  padding: 11px 20px 10px;
  font-size: 9px; letter-spacing: 0.18em; text-transform: uppercase;
  color: #666; display: block; border-bottom: 1px solid var(--dim);
  font-weight: 600; background: var(--off);
}
/* 2-column topic table */
.topic-table {
  display: grid; grid-template-columns: 1fr 1fr;
}
.tt-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 11px 18px;
  border-bottom: 1px solid var(--dim);
  border-right: 1px solid var(--dim);
  font-size: 13px; color: var(--black); letter-spacing: 0.02em;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.12s, color 0.12s, padding-left 0.15s;
}
.tt-row:nth-child(2n) { border-right: none; }
.tt-row:nth-last-child(-n+2) { border-bottom: none; }
.tt-row:hover {
  background: var(--black); color: var(--white);
  padding-left: 22px;
}
.tt-row:hover .tt-count { background: rgba(255,255,255,0.15); border-color: rgba(255,255,255,0.2); color: var(--white); }
.tt-name { flex: 1; }
.tt-count {
  font-size: 11px; color: #666; background: var(--off);
  padding: 2px 8px; border-radius: 2px; border: 1px solid var(--dim);
  flex-shrink: 0; margin-left: 8px; font-weight: 700;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
}

/* ── Col 3: Right column ── */
.hero-col-right {
  justify-content: flex-start;
}
.lang-stack {
  flex: 1; display: flex; flex-direction: column;
  overflow: hidden; min-height: 0;
}
.lang-stack-label {
  padding: 16px 20px;
  font-size: 9px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--mid);
  border-bottom: 1px solid var(--dim);
  flex-shrink: 0;
}
.lang-item {
  padding: 13px 20px;
  font-size: 12px; color: var(--soft);
  border-bottom: 1px solid var(--dim);
  letter-spacing: 0.04em;
  flex-shrink: 0;
}
.lang-item:last-child { border-bottom: none; }
.hero-col-cta {
  padding: 20px;
  border-top: 1px solid var(--dim);
  background: var(--black); color: var(--white);
  flex-shrink: 0;
}
.hero-col-cta-text {
  font-size: 9px; letter-spacing: 0.2em; text-transform: uppercase;
  color: rgba(255,255,255,0.4); margin-bottom: 4px;
}
.hero-col-cta-name {
  font-family: var(--font-display); font-size: 18px; font-weight: 800;
  letter-spacing: -0.01em; color: var(--white);
}

/* ── Interactive Topic Tree ── */
.hero-3d {
  flex: 1;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  padding: 0; position: relative; overflow: hidden;
  border-top: 1px solid var(--dim);
}
#tree-canvas {
  display: block; width: 100%; height: 100%;
  cursor: none;
}
.hero-3d-hint {
  position: absolute; bottom: 10px; left: 50%; transform: translateX(-50%);
  font-size: 9px; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--mid); white-space: nowrap; pointer-events: none;
}

/* ── Shared buttons ── */
.btn-primary {
  padding: 13px 26px; font-family: var(--font-body); font-size: 11px;
  letter-spacing: 0.12em; text-transform: uppercase;
  background: var(--black); color: var(--white); border: none;
  box-shadow: 4px 4px 0 rgba(10,10,10,0.18), var(--shadow-md);
  transition: box-shadow 0.15s, transform 0.15s; white-space: nowrap;
}
.btn-primary:hover { box-shadow: 6px 6px 0 rgba(10,10,10,0.22), var(--shadow-lg); transform: translate(-1px,-1px); }
.btn-primary:active { box-shadow: 2px 2px 0 rgba(10,10,10,0.18); transform: translate(1px,1px); }
.btn-hero {
  padding: 16px 36px; font-size: 13px; letter-spacing: 0.14em;
  display: inline-flex; align-items: center; gap: 12px;
}
.btn-hero:hover { box-shadow: 8px 8px 0 rgba(10,10,10,0.2), var(--shadow-lg); transform: translate(-2px,-2px); }
.btn-arrow { display: inline-block; transition: transform 0.2s ease; font-size: 16px; }
.btn-hero:hover .btn-arrow { transform: translateX(5px); }

.topic-grid {
  display: flex; flex-wrap: wrap; gap: 7px;
  margin: 0;
}
.tg-pill {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 14px;
  background: var(--white); border: 1px solid var(--dim);
  font-family: var(--font-body); font-size: 11px;
  letter-spacing: 0.06em; color: var(--soft);
  box-shadow: 2px 2px 0 rgba(10,10,10,0.06);
  transition: background 0.13s, border-color 0.13s, transform 0.12s, box-shadow 0.12s;
  white-space: nowrap;
}
.tg-pill:hover {
  background: var(--black); color: var(--white); border-color: var(--black);
  transform: translate(-1px, -1px); box-shadow: 3px 3px 0 rgba(10,10,10,0.18);
}
.tg-pill.active {
  background: var(--black); color: var(--white); border-color: var(--black);
  box-shadow: 3px 3px 0 rgba(10,10,10,0.22);
}
.tg-count {
  font-size: 9px; opacity: 0.5; padding: 1px 5px;
  border: 1px solid currentColor; border-radius: 2px; letter-spacing: 0.04em;
}

/* ── Topic dropdown panel ── */
.topic-panel {
  display: none;
  background: var(--white);
  border: 1px solid var(--black);
  box-shadow: 4px 4px 0 rgba(10,10,10,0.12), var(--shadow-md);
  margin: 10px 0 0;
  overflow: hidden;
}
.topic-panel.open {
  display: flex; flex-direction: column;
  animation: panelIn 0.16s ease forwards;
}
@keyframes panelIn {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}
.topic-panel-head {
  display: flex; align-items: center; gap: 10px;
  padding: 11px 16px; border-bottom: 1px solid var(--dim);
  background: var(--off);
}
.topic-panel-name {
  font-size: 11px; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase; flex: 1; color: var(--black);
}
.topic-panel-count { font-size: 10px; color: var(--mid); }
.topic-panel-close {
  background: none; border: 1px solid var(--dim); padding: 2px 7px;
  font-size: 11px; color: var(--mid); line-height: 1.5;
  transition: all 0.12s;
}
.topic-panel-close:hover { background: var(--black); color: var(--white); border-color: var(--black); }

.topic-panel-list {
  display: grid; grid-template-columns: repeat(2, 1fr);
  max-height: 230px; overflow-y: auto;
}
.tp-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 14px;
  border-bottom: 1px solid var(--dim); border-right: 1px solid var(--dim);
  font-size: 12px; color: var(--soft);
  transition: background 0.1s, color 0.1s; text-decoration: none;
}
.tp-item:nth-child(2n) { border-right: none; }
.tp-item:hover { background: var(--off); color: var(--black); }
.tp-diff {
  font-size: 9px; letter-spacing: 0.06em; text-transform: uppercase;
  padding: 1px 5px; border: 1px solid; flex-shrink: 0; margin-left: 8px;
}
.tp-diff.easy   { border-color: var(--dim);   color: var(--mid); }
.tp-diff.medium { border-color: var(--mid);   color: var(--soft); }
.tp-diff.hard   { border-color: var(--black); color: var(--black); font-weight: 700; }

.topic-panel-link {
  display: block; padding: 9px 16px; font-size: 11px; letter-spacing: 0.08em;
  color: var(--black); border-top: 1px solid var(--dim); background: var(--off);
  transition: background 0.12s; text-align: right;
  text-decoration: none;
}
.topic-panel-link:hover { background: var(--dim); }

/* Dark marquee strip */
.topics-marquee {
  overflow: hidden; height: 42px; display: flex; align-items: center;
  background: var(--black); border-bottom: 1px solid rgba(255,255,255,0.06);
}
.topics-marquee .ticker-inner { color: rgba(255,255,255,0.35); animation-duration: 24s; letter-spacing: 0.24em; }

/* ════════════════════════════════════════════════════════════
   INDEX — FEATURE CELLS (3D tilt effect via JS)
════════════════════════════════════════════════════════════ */
.features {
  display: grid; grid-template-columns: repeat(3, 1fr);
  border-bottom: 1px solid var(--dim);
}
.feature-cell {
  padding: 52px 44px;
  border-right: 1px solid var(--dim);
  background: var(--white);
  position: relative; overflow: hidden;
  transition: background 0.3s, box-shadow 0.3s;
  /* perspective for tilt */
  perspective: 600px;
}
.feature-cell:last-child { border-right: none; }

/* Gloss sheen that moves on hover */
.feature-cell::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(circle 120px at var(--mx,50%) var(--my,50%), rgba(255,255,255,0.55) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}
.feature-cell:hover::after { opacity: 1; }
.feature-cell:hover {
  background: var(--off);
  box-shadow: var(--shadow-md), inset 0 1px 0 rgba(255,255,255,0.8);
  z-index: 2;
}

.feature-num {
  font-family: var(--font-display); font-size: 42px; font-weight: 800;
  color: var(--dim); margin-bottom: 24px; display: block;
  transition: color 0.25s, text-shadow 0.25s, transform 0.25s;
  letter-spacing: -0.03em;
}
.feature-cell:hover .feature-num {
  color: var(--mid);
  text-shadow: 3px 3px 0 rgba(10,10,10,0.08);
  transform: translateX(3px) translateY(-2px);
}
.feature-title {
  font-size: 14px; font-weight: 500; letter-spacing: 0.06em; margin-bottom: 12px;
  transition: transform 0.25s;
}
.feature-cell:hover .feature-title { transform: translateX(2px); }
.feature-body { font-size: 12px; color: var(--soft); line-height: 1.9; }

/* ════════════════════════════════════════════════════════════
   INDEX — TOPICS LIST
════════════════════════════════════════════════════════════ */
.topics-section { padding: 0; }
.topics-header {
  padding: 26px 40px; border-bottom: 1px solid var(--dim);
  display: flex; align-items: baseline; gap: 16px;
  background: var(--white); box-shadow: var(--shadow-sm);
}
.topics-header h2 { font-family: var(--font-display); font-size: 22px; font-weight: 800; letter-spacing: -0.02em; }
.topics-header span { font-size: 10px; color: var(--mid); letter-spacing: 0.14em; text-transform: uppercase; }

.topics-list { display: flex; flex-direction: column; }
.topic-row {
  display: grid; grid-template-columns: 52px 1fr auto 32px;
  align-items: center; padding: 0 40px; height: 56px;
  border-bottom: 1px solid var(--dim);
  background: var(--paper);
  transition: background 0.15s, box-shadow 0.15s, padding-left 0.2s;
  position: relative;
}
.topic-row:hover {
  background: var(--white);
  box-shadow: var(--shadow-sm); z-index: 1;
  padding-left: 48px;
}
.topic-idx  { font-size: 10px; color: var(--dim); font-family: var(--font-display); }
.topic-name { font-size: 13px; letter-spacing: 0.04em; }
.topic-count { font-size: 10px; color: var(--mid); }
.topic-arrow {
  font-size: 11px; color: var(--mid); opacity: 0;
  transform: translateX(-6px); transition: opacity 0.2s, transform 0.2s;
}
.topic-row:hover .topic-arrow { opacity: 1; transform: translateX(0); }
.topic-row:hover .topic-count  { opacity: 0; transition: opacity 0.1s; }

/* CTA */
.cta-full {
  min-height: 300px; display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  text-align: center; padding: 60px 40px;
  background: var(--black); color: var(--white); position: relative; overflow: hidden;
}
.cta-full::before {
  content: '150';
  position: absolute; font-family: var(--font-display);
  font-size: 400px; line-height: 1; letter-spacing: -0.05em;
  color: rgba(255,255,255,0.02); pointer-events: none;
  top: 50%; left: 50%; transform: translate(-50%,-50%);
}
.cta-full h2 {
  font-family: var(--font-display); font-size: clamp(32px,5vw,64px);
  font-weight: 800; letter-spacing: -0.03em;
  margin-bottom: 14px; text-shadow: 0 2px 16px rgba(255,255,255,0.06);
}
.cta-full p { font-size: 12px; color: rgba(255,255,255,0.38); margin-bottom: 32px; letter-spacing: 0.08em; }
.btn-white {
  padding: 13px 34px; font-family: var(--font-body); font-size: 11px;
  letter-spacing: 0.12em; text-transform: uppercase;
  background: var(--white); color: var(--black); border: none;
  box-shadow: 4px 4px 0 rgba(255,255,255,0.12), 0 8px 32px rgba(0,0,0,0.4);
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn-white:hover { transform: translate(-2px,-2px); box-shadow: 6px 6px 0 rgba(255,255,255,0.16), 0 14px 44px rgba(0,0,0,0.45); }

/* ── Creator / Contact Section ── */
.creator-section {
  background: var(--black); color: var(--white);
  border-top: 1px solid #222;
}
.creator-inner {
  display: grid; grid-template-columns: 1fr 1fr 1fr;
  min-height: 200px;
}
.creator-left {
  padding: 48px 40px;
  border-right: 1px solid #222;
  display: flex; flex-direction: column; justify-content: center;
}
.creator-tag {
  font-size: 9px; letter-spacing: 0.24em; text-transform: uppercase;
  color: rgba(255,255,255,0.35); margin-bottom: 10px;
}
.creator-name {
  font-family: var(--font-display); font-size: 42px; font-weight: 800;
  letter-spacing: -0.02em; line-height: 1; color: var(--white);
  margin-bottom: 6px;
}
.creator-handle {
  font-size: 12px; color: rgba(255,255,255,0.35); letter-spacing: 0.06em;
}

.creator-links {
  padding: 48px 40px;
  border-right: 1px solid #222;
  display: flex; flex-direction: column; justify-content: center; gap: 16px;
}
.creator-link {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 16px;
  border: 1px solid #333;
  text-decoration: none; color: var(--white);
  transition: background 0.15s, border-color 0.15s;
}
.creator-link:hover { background: #1a1a1a; border-color: #555; }
.creator-link-icon {
  width: 36px; height: 36px; border-radius: 4px;
  background: #222; border: 1px solid #333;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0; color: rgba(255,255,255,0.7);
  transition: background 0.15s;
}
.creator-link:hover .creator-link-icon { background: #2a2a2a; }
.creator-link-body { flex: 1; display: flex; flex-direction: column; gap: 2px; }
.creator-link-platform {
  font-size: 10px; letter-spacing: 0.12em; text-transform: uppercase;
  color: rgba(255,255,255,0.4); font-weight: 600;
}
.creator-link-handle {
  font-size: 12px; color: rgba(255,255,255,0.8);
}
.creator-link-arrow {
  font-size: 14px; color: rgba(255,255,255,0.3);
  transition: color 0.15s, transform 0.15s;
}
.creator-link:hover .creator-link-arrow { color: var(--white); transform: translate(2px,-2px); }

.creator-right {
  padding: 48px 40px;
  display: flex; flex-direction: column; justify-content: space-between;
}
.creator-cta {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 14px 28px; align-self: flex-start;
  font-family: var(--font-body); font-size: 12px; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase;
  background: var(--white); color: var(--black);
  text-decoration: none;
  box-shadow: 4px 4px 0 rgba(255,255,255,0.1);
  transition: transform 0.15s, box-shadow 0.15s;
}
.creator-cta:hover { transform: translate(-2px,-2px); box-shadow: 6px 6px 0 rgba(255,255,255,0.15); }
.creator-copy {
  font-size: 10px; color: rgba(255,255,255,0.25);
  letter-spacing: 0.1em; text-transform: uppercase;
}

@media (max-width: 768px) {
  .creator-inner { grid-template-columns: 1fr; }
  .creator-left, .creator-links { border-right: none; border-bottom: 1px solid #222; }
}

/* ════════════════════════════════════════════════════════════
   TRACKER PAGE
════════════════════════════════════════════════════════════ */
.tracker-wrap { display: flex; min-height: 100vh; padding-top: 52px; }

.sidebar {
  width: 256px; flex-shrink: 0;
  background: var(--white);
  border-right: 1px solid var(--dim);
  box-shadow: 2px 0 12px rgba(10,10,10,0.05);
  position: fixed; top: 52px; left: 0; bottom: 0;
  overflow-y: auto; display: flex; flex-direction: column; z-index: 100;
}
.sidebar-head { padding: 18px 18px 12px; border-bottom: 1px solid var(--dim); background: var(--off); }
.sidebar-head h2 { font-family: var(--font-display); font-size: 16px; font-weight: 800; letter-spacing: -0.02em; margin-bottom: 12px; }
.sidebar-search input {
  width: 100%; padding: 8px 10px; font-family: var(--font-body); font-size: 12px;
  background: var(--white); border: 1px solid var(--dim); color: var(--black);
  box-shadow: inset 0 1px 3px rgba(10,10,10,0.05);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.sidebar-search input:focus { outline: none; border-color: var(--black); box-shadow: inset 0 1px 3px rgba(10,10,10,0.07), 0 0 0 3px rgba(10,10,10,0.04); }
.sidebar-search input::placeholder { color: var(--mid); }

.sidebar-filters { display: flex; padding: 10px 18px; border-bottom: 1px solid var(--dim); background: var(--off); }
.sf-btn {
  flex: 1; padding: 5px 0; font-family: var(--font-body); font-size: 10px;
  letter-spacing: 0.1em; text-transform: uppercase;
  background: var(--white); border: 1px solid var(--dim); color: var(--mid);
  transition: all 0.12s; margin-right: -1px;
  box-shadow: 1px 1px 0 rgba(10,10,10,0.05);
}
.sf-btn.active { background: var(--black); color: var(--white); border-color: var(--black); z-index: 1; box-shadow: 2px 2px 0 rgba(10,10,10,0.2); }
.sf-btn:hover:not(.active) { border-color: var(--black); color: var(--black); z-index: 1; }

.sidebar-topics { flex: 1; overflow-y: auto; padding: 6px 0; }
.sb-topic {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 18px; font-size: 11px; color: var(--soft); letter-spacing: 0.04em;
  border-left: 2px solid transparent; transition: all 0.12s;
}
.sb-topic:hover { color: var(--black); background: var(--off); }
.sb-topic.active { color: var(--black); border-left-color: var(--black); background: var(--off); font-weight: 500; }
.sb-topic-cnt { font-size: 10px; color: var(--dim); }

.tracker-main {
  margin-left: 256px; flex: 1; background: var(--paper);
  display: flex; flex-direction: column;
}
.tracker-topbar {
  padding: 18px 36px; border-bottom: 1px solid var(--dim);
  display: flex; align-items: center; justify-content: space-between;
  position: sticky; top: 52px; z-index: 50;
  background: rgba(242,240,235,0.92); backdrop-filter: blur(8px);
  box-shadow: 0 2px 10px rgba(10,10,10,0.05);
}
.tracker-topbar h1 { font-family: var(--font-display); font-size: 18px; font-weight: 800; letter-spacing: -0.02em; }
.tb-right { font-size: 10px; color: var(--mid); letter-spacing: 0.1em; text-transform: uppercase; }

.t-group { border-bottom: 1px solid var(--dim); scroll-margin-top: 104px; }
.t-group-hdr {
  display: flex; align-items: center; justify-content: space-between;
  padding: 11px 36px; background: var(--off);
  border-bottom: 1px solid var(--dim);
  box-shadow: 0 1px 0 rgba(10,10,10,0.03);
  transition: background 0.15s;
}
.t-group-hdr:hover { background: var(--dim); }
.t-group-hdr h3 { font-family: var(--font-display); font-size: 13px; font-weight: 800; letter-spacing: 0.04em; text-transform: uppercase; }
.t-group-hdr span { font-size: 10px; color: var(--mid); letter-spacing: 0.1em; text-transform: uppercase; }
.t-group-chevron { font-size: 10px; color: var(--mid); transition: transform 0.2s; margin-left: 12px; }
.t-group-chevron.open { transform: rotate(90deg); }

/* ── Problem row checkbox ── */
.p-row {
  display: grid; grid-template-columns: 52px 1fr 32px 90px 34px;
  align-items: center; padding: 0 36px; height: 52px;
  border-bottom: 1px solid var(--dim); background: var(--white);
  transition: background 0.1s, box-shadow 0.1s, padding-left 0.15s;
  position: relative;
}
.p-row:hover { background: var(--off); box-shadow: var(--shadow-sm); z-index: 1; padding-left: 42px; }
.p-row:last-child { border-bottom: none; }
.p-row-done .p-name { text-decoration: line-through; color: var(--mid); }
.p-num {
  font-size: 13px; font-weight: 800;
  color: var(--black); letter-spacing: -0.01em;
}
.p-name { font-size: 13px; }
.p-lc-link {
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px; font-size: 13px; color: var(--mid);
  border-radius: 3px; text-decoration: none;
  transition: background 0.12s, color 0.12s;
}
.p-lc-link:hover { background: #f89f1b; color: #fff; }
.p-diff-badge {
  font-size: 11px; letter-spacing: 0.06em; text-transform: uppercase;
  padding: 4px 12px; font-weight: 800; border: none;
}
.p-diff-badge.easy   { background: #dcf5e3; color: #1a6b2e; }
.p-diff-badge.medium { background: #feefd0; color: #8a4a00; }
.p-diff-badge.hard   { background: #fddcdc; color: #a31111; }

/* Row checkbox */
.p-checkbox {
  width: 22px; height: 22px; border-radius: 4px;
  border: 1.5px solid var(--dim);
  background: var(--white);
  display: inline-flex; align-items: center; justify-content: center;
  margin: auto;
  transition: background 0.15s, border-color 0.15s, transform 0.12s;
  flex-shrink: 0;
}
.p-checkbox:hover { border-color: var(--black); transform: scale(1.1); }
.p-checkbox.checked {
  background: var(--black); border-color: var(--black);
  color: var(--white);
}

.empty-state { padding: 80px; text-align: center; color: var(--mid); font-size: 12px; letter-spacing: 0.1em; }

/* ── Modal footer completion checkbox ── */
.m-complete-wrap {
  display: flex; align-items: center; gap: 10px;
  margin-right: auto; padding: 6px 10px;
  border: 1px solid var(--dim); border-radius: 4px;
  background: var(--white);
  transition: background 0.15s, border-color 0.15s;
}
.m-complete-wrap:hover { background: var(--off); border-color: var(--black); }
.m-complete-cb {
  width: 20px; height: 20px; border-radius: 4px;
  border: 1.5px solid var(--dim); background: var(--white);
  display: inline-flex; align-items: center; justify-content: center;
  flex-shrink: 0; color: transparent;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}
.m-complete-cb.checked {
  background: var(--black); border-color: var(--black); color: var(--white);
}
.m-complete-wrap:hover .m-complete-cb { border-color: var(--black); }
.m-check-icon { display: block; }
.m-complete-label {
  font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--soft); font-weight: 600; white-space: nowrap;
  transition: color 0.15s;
}
.m-complete-wrap:hover .m-complete-label { color: var(--black); }

/* ════════════════════════════════════════════════════════════
   MODAL
════════════════════════════════════════════════════════════ */
.modal-overlay {
  position: fixed; inset: 0; z-index: 1000;
  background: rgba(10,10,10,0.55); backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center; padding: 16px;
  opacity: 0; pointer-events: none; transition: opacity 0.25s;
}
.modal-overlay.open { opacity: 1; pointer-events: all; }
.modal-box {
  background: var(--white); border: 1px solid var(--dim);
  box-shadow: var(--shadow-xl), 0 0 0 1px rgba(10,10,10,0.03);
  width: 96vw; max-width: 1600px; max-height: 96vh; height: 96vh;
  display: flex; flex-direction: column;
  transform: translateY(20px) scale(0.985);
  transition: transform 0.3s cubic-bezier(0.25,0.46,0.45,0.94);
  overflow: hidden;
}
.modal-overlay.open .modal-box { transform: translateY(0) scale(1); }

.modal-head {
  padding: 20px 26px 16px; border-bottom: 1px solid var(--dim);
  display: flex; align-items: flex-start; gap: 16px;
  background: var(--off); box-shadow: 0 1px 0 rgba(10,10,10,0.04);
}
.modal-head-info { flex: 1; }
.modal-head-num { font-size: 9px; color: var(--mid); letter-spacing: 0.2em; text-transform: uppercase; margin-bottom: 5px; }
.modal-head-title { font-family: var(--font-display); font-size: 22px; font-weight: 800; letter-spacing: -0.02em; line-height: 1.1; margin-bottom: 8px; }
.modal-head-meta { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.modal-close {
  background: var(--white); border: 1px solid var(--dim); padding: 6px 11px;
  font-size: 14px; line-height: 1; color: var(--soft);
  box-shadow: var(--shadow-sm); transition: all 0.12s;
}
.modal-close:hover { background: var(--black); color: var(--white); border-color: var(--black); box-shadow: 2px 2px 0 rgba(10,10,10,0.2); }

/* LeetCode external link button */
.leetcode-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 12px;
  font-family: var(--font-body); font-size: 10px;
  letter-spacing: 0.08em; text-transform: uppercase; font-weight: 700;
  color: #f89f1b; background: rgba(248,159,27,0.08);
  border: 1px solid rgba(248,159,27,0.35);
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.12s;
  white-space: nowrap;
}
.leetcode-btn:hover {
  background: #f89f1b; color: #fff;
  border-color: #f89f1b;
  transform: translateY(-1px);
}
.leetcode-btn svg { flex-shrink: 0; }

.modal-body { flex: 1; overflow: hidden; display: grid; grid-template-columns: 1fr 1fr; min-height: 0; }
.modal-left { padding: 0; border-right: 1px solid var(--dim); overflow-y: auto; background: var(--white); display: flex; flex-direction: column; }
.modal-right { padding: 20px 24px; display: flex; flex-direction: column; gap: 12px; overflow-y: auto; background: var(--paper); height: 100%; }

/* ── Section label — bolder, more distinct ── */
.section-label {
  font-size: 9px; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase;
  color: var(--black); margin-bottom: 12px;
  display: flex; align-items: center; gap: 10px;
}
.section-label::after { content: ''; flex: 1; height: 1px; background: var(--dim); }

/* ── Description block ── */
.modal-section-desc {
  padding: 22px 26px 20px;
  border-bottom: 1px solid var(--dim);
  background: var(--white);
}
/* Highlighted first sentence treatment */
.prob-description {
  font-size: 13.5px; color: var(--black); line-height: 1.9;
  margin-bottom: 0; font-weight: 400;
  border-left: 3px solid var(--black);
  padding-left: 14px;
  background: linear-gradient(to right, rgba(10,10,10,0.03) 0%, transparent 100%);
  padding-top: 4px; padding-bottom: 4px;
}

/* ── Examples block — code card style ── */
.modal-section-examples {
  padding: 18px 26px;
  border-bottom: 1px solid var(--dim);
  background: var(--paper);
}
.prob-example {
  background: #1e1e1e;
  border-left: 3px solid #2d7a3a;
  padding: 14px 16px; font-size: 12px; line-height: 1.9;
  margin-bottom: 10px;
  font-family: var(--font-body);
  color: rgba(255,255,255,0.75);
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.prob-example:last-child { margin-bottom: 0; }
.prob-example:hover {
  background: #0d1f12;
  border-left-color: #4ade80;
  color: rgba(255,255,255,0.95);
}
.prob-example strong {
  font-weight: 700; display: block; margin-bottom: 8px;
  font-size: 9px; letter-spacing: 0.2em; color: rgba(255,255,255,0.3);
  text-transform: uppercase; transition: color 0.2s;
}
.prob-example:hover strong { color: rgba(100,255,130,0.6); }
.prob-example .ex-row { margin-bottom: 4px; display: flex; gap: 8px; align-items: baseline; }
.prob-example .ex-label {
  color: rgba(255,255,255,0.35); font-size: 10px;
  letter-spacing: 0.08em; text-transform: uppercase;
  min-width: 44px; flex-shrink: 0; transition: color 0.2s;
}
.prob-example:hover .ex-label { color: rgba(100,255,130,0.5); }
.prob-example .ex-val {
  color: #86efac; font-family: var(--font-body); transition: color 0.2s;
}
.prob-example:hover .ex-val { color: #4ade80; }

/* ── Constraints block ── */
.modal-section-constraints {
  padding: 16px 26px 20px;
  background: var(--off);
  border-top: 1px solid var(--dim);
  flex: 1;
}
.modal-section-constraints .section-label { color: var(--mid); }
.modal-section-constraints .section-label::after { background: var(--dim); }
.constraints { font-size: 12px; line-height: 2; color: var(--soft); }
.constraints strong { color: var(--black); font-weight: 700; }

/* ── Language tabs ── */
.lang-tabs { display: flex; flex-wrap: wrap; margin-bottom: 0; }
.lang-tab {
  padding: 6px 14px; font-family: var(--font-body); font-size: 10px;
  letter-spacing: 0.08em; text-transform: uppercase;
  background: var(--off); border: 1px solid var(--dim); color: var(--mid);
  margin-right: -1px; margin-bottom: -1px;
  transition: all 0.1s; position: relative;
}
.lang-tab.active { background: var(--black); color: var(--white); border-color: var(--black); z-index: 1; }
.lang-tab:hover:not(.active) { background: var(--white); color: var(--black); border-color: var(--black); z-index: 1; }
.lang-tab.has-sol::before {
  content: ''; position: absolute; top: 4px; right: 4px;
  width: 4px; height: 4px; border-radius: 50%; background: #2d7a3a;
}
.lang-tab.active.has-sol::before { background: var(--white); }

/* ════════════════════════════════════════════════════════════
   CODE EDITOR — clean white, minimal border, file-label header
════════════════════════════════════════════════════════════ */
.editor-wrap {
  flex: 1; display: flex; flex-direction: column;
  border: 1px solid var(--dim);
  overflow: hidden;
}

/* Slim header: filename only */
.editor-titlebar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 7px 14px;
  background: var(--off);
  border-bottom: 1px solid var(--dim);
  flex-shrink: 0;
}
.editor-dot { display: none; }
.editor-filename {
  font-size: 11px; color: var(--mid);
  letter-spacing: 0.06em; font-family: var(--font-body);
}
.editor-kb-hint {
  font-size: 10px; color: var(--mid); letter-spacing: 0.06em;
}

/* Line numbers + textarea */
.editor-body {
  flex: 1; display: flex; overflow: hidden; background: var(--white);
  position: relative; min-height: 320px;
}
.editor-gutter {
  padding: 14px 10px 14px 14px;
  background: var(--off);
  border-right: 1px solid var(--dim);
  font-family: var(--font-body); font-size: 12.5px;
  line-height: 1.75; color: var(--mid);
  text-align: right; user-select: none; pointer-events: none;
  min-width: 44px; flex-shrink: 0;
  white-space: pre; overflow: hidden;
}
.code-editor {
  flex: 1; padding: 14px 18px;
  font-family: var(--font-body); font-size: 12.5px;
  background: var(--white); color: var(--black);
  border: none; resize: none;
  line-height: 1.75; tab-size: 2; width: 100%;
  caret-color: var(--black);
  outline: none;
  min-height: 320px;
}
.code-editor::placeholder { color: var(--dim); font-style: italic; }
.code-editor:focus { outline: none; background: var(--white); }

/* No status bar */
.editor-statusbar { display: none; }

.notes-editor {
  width: 100%; min-height: 72px; padding: 10px 14px;
  font-family: var(--font-body); font-size: 12px;
  background: var(--off); border: 1px solid var(--dim); color: var(--black);
  resize: vertical; line-height: 1.7;
  box-shadow: inset 0 1px 3px rgba(10,10,10,0.04);
  transition: border-color 0.15s;
}
.notes-editor:focus { outline: none; border-color: var(--black); }
.notes-editor::placeholder { color: var(--mid); }

.modal-foot {
  padding: 12px 26px; border-top: 1px solid var(--dim);
  display: flex; align-items: center; justify-content: flex-end; gap: 8px;
  background: var(--off); box-shadow: 0 -1px 0 rgba(10,10,10,0.04);
}
.save-msg { font-size: 10px; color: var(--soft); letter-spacing: 0.1em; margin-right: auto; opacity: 0; transition: opacity 0.3s; }
.save-msg.show { opacity: 1; }
.btn-cancel {
  padding: 8px 18px; font-family: var(--font-body); font-size: 11px;
  letter-spacing: 0.08em; text-transform: uppercase;
  background: var(--white); border: 1px solid var(--dim); color: var(--soft);
  box-shadow: var(--shadow-sm); transition: all 0.12s;
}
.btn-cancel:hover { border-color: var(--black); color: var(--black); }
.btn-save {
  padding: 8px 22px; font-family: var(--font-body); font-size: 11px;
  font-weight: 500; letter-spacing: 0.1em; text-transform: uppercase;
  background: var(--black); color: var(--white); border: 1px solid var(--black);
  box-shadow: 3px 3px 0 rgba(10,10,10,0.15), var(--shadow-sm);
  transition: all 0.12s;
}
.btn-save:hover { box-shadow: 5px 5px 0 rgba(10,10,10,0.2); transform: translate(-1px,-1px); }
.btn-save:active { box-shadow: 1px 1px 0 rgba(10,10,10,0.15); transform: translate(1px,1px); }

/* ── Responsive ── */
@media (max-width: 900px) {
  .modal-body { grid-template-columns: 1fr; grid-template-rows: auto 1fr; }
  .modal-left { border-right: none; border-bottom: 1px solid var(--dim); max-height: 35vh; overflow-y: auto; flex-shrink: 0; }
}
@media (max-width: 1100px) {
  .hero-main { grid-template-columns: 1fr 1fr; }
  .hero-col-right { display: none; }
}
@media (max-width: 768px) {
  /* ── Prevent ANY horizontal overflow at the root ── */
  html, body { overflow-x: hidden; max-width: 100vw; }

  /* ── Hero section fills full width ── */
  .hero { width: 100%; }
  .hero-main { grid-template-columns: 1fr; width: 100%; }
  .hero-col-gauge { border-right: none; border-bottom: 1px solid var(--dim); }

  /* Reduce side padding on title col so content doesn't overflow */
  .hero-col-title { padding: 28px 16px; }

  /* Hero meta — make all 3 stat boxes visible and compact */
  .hero-meta { width: 100%; }
  .hero-meta-row { padding: 10px 10px; }
  .hero-meta-num { font-size: 22px; }

  /* Ticker — full viewport width, no overflow */
  .hero-ticker { overflow: hidden; width: 100%; }
  .topics-marquee { overflow: hidden; width: 100%; }
  .ticker-inner { white-space: nowrap; }

  /* Features — full width, single column */
  .features { grid-template-columns: 1fr; width: 100%; }
  .feature-cell { border-right: none; border-bottom: 1px solid var(--dim); padding: 36px 20px; }

  /* Topics section — full width, tighter padding */
  .topics-section { width: 100%; }
  .topics-header { padding: 18px 16px; }
  .topic-row { padding: 0 16px; grid-template-columns: 36px 1fr auto 24px; }
  .topic-row:hover { padding-left: 20px; }

  /* CTA section — full width */
  .cta-full { padding: 48px 20px; min-height: 240px; width: 100%; }
  .cta-full h2 { font-size: clamp(26px, 8vw, 48px); word-break: break-word; }
  .cta-full p { font-size: 11px; padding: 0 8px; }
}


/* ════════════════════════════════════════════════════════════
   HERO ROADMAP
════════════════════════════════════════════════════════════ */
.hero-roadmap {
  border-top: 1px solid var(--dim);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.roadmap-header {
  padding: 10px 40px;
  border-bottom: 1px solid var(--dim);
  flex-shrink: 0;
}
.roadmap-header-label {
  font-size: 9px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--mid);
  font-weight: 600;
}
.roadmap-svg-wrap {
  overflow-y: auto;
  overflow-x: hidden;
  padding: 12px 16px 20px;
  max-height: 520px;
}
.rm-node { cursor: pointer; }
.rm-node:hover rect { opacity: 0.85; }

/* ════════════════════════════════════════════════════════════
   INDEX FOOTER
════════════════════════════════════════════════════════════ */
.site-footer {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
  min-height: 68px;
  padding: 0 48px;
  background: #ebe8e3;
  border-top: 4px solid var(--black);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #6e6a66;
}

.footer-left,
.footer-right {
  white-space: nowrap;
}

.footer-right {
  justify-self: end;
}

.footer-right strong {
  color: var(--black);
}

.footer-center {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  min-width: 0;
}

.footer-contact {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--black);
  text-transform: none;
  letter-spacing: 0.08em;
  font-size: 12px;
}

.footer-contact:hover {
  opacity: 0.72;
}

.footer-icon {
  width: 26px;
  height: 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--black);
  flex-shrink: 0;
}

.footer-icon svg {
  width: 100%;
  height: 100%;
}

.footer-divider {
  color: #7f7a75;
  font-size: 14px;
}

@media (max-width: 1200px) {
  .site-footer {
    grid-template-columns: 1fr;
    justify-items: center;
    padding: 18px 24px;
    gap: 12px;
    text-align: center;
  }

  .footer-right {
    justify-self: center;
  }

  .footer-center {
    flex-wrap: wrap;
    gap: 12px;
  }
}

@media (max-width: 640px) {
  .footer-center {
    flex-direction: column;
  }

  .footer-divider {
    display: none;
  }

  .footer-contact {
    font-size: 11px;
    word-break: break-all;
  }

  .site-footer {
    padding: 16px;
  }
}

/* ════════════════════════════════════════════════════════════
   ARTICLE-STYLE SOLUTION WRITER
════════════════════════════════════════════════════════════ */
.sol-tabs-wrap {
  padding: 10px 20px 8px;
  border-bottom: 1px solid var(--dim);
  display: flex; align-items: center; flex-wrap: wrap; gap: 8px;
  flex-shrink: 0;
}
.sol-approach-tabs { display: flex; flex-wrap: wrap; gap: 0; flex: 1; }
.sol-approach-tab {
  padding: 5px 14px; font-family: var(--font-body); font-size: 10px;
  letter-spacing: 0.08em; text-transform: uppercase;
  background: var(--off); border: 1px solid var(--dim); color: var(--mid);
  margin-right: -1px; transition: all 0.12s; position: relative;
}
.sol-approach-tab.active { background: var(--black); color: var(--white); border-color: var(--black); z-index: 1; }
.sol-approach-tab:hover:not(.active) { background: var(--white); color: var(--black); border-color: var(--black); z-index: 1; }
.sol-approach-tab .rm-tab { margin-left: 6px; opacity: 0.5; font-size: 11px; }
.sol-approach-tab:hover .rm-tab { opacity: 1; }
.sol-add-approach {
  padding: 5px 12px; font-family: var(--font-body); font-size: 10px;
  letter-spacing: 0.08em; text-transform: uppercase;
  background: transparent; border: 1px dashed var(--dim); color: var(--mid);
  transition: all 0.12s; white-space: nowrap;
}
.sol-add-approach:hover { border-color: var(--black); color: var(--black); }

.sol-article {
  flex: 1; overflow-y: auto; padding: 20px 24px 28px 16px;
  display: flex; flex-direction: column; gap: 22px;
}
.sol-field { display: flex; flex-direction: column; gap: 4px; }
.sol-label {
  font-size: 9px; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--mid); font-weight: 600;
}
.sol-input {
  width: 100%; padding: 8px 12px;
  font-family: var(--font-body); font-size: 12px;
  background: var(--white); border: 1px solid var(--dim); color: var(--black);
  transition: border-color 0.15s; outline: none;
}
.sol-input:focus { border-color: var(--black); }
.sol-textarea {
  width: 100%; padding: 10px 12px;
  font-family: var(--font-body); font-size: 13px; line-height: 1.8;
  background: var(--off); border: 1px solid var(--dim); color: var(--black);
  resize: vertical; outline: none; transition: border-color 0.15s;
}
#m-intuition  { min-height: 240px; }
#m-algorithm  { min-height: 320px; }
.sol-textarea:focus { border-color: var(--black); background: var(--white); }
.sol-complexity-row { flex-direction: row; gap: 12px; }
.sol-field-half { flex: 1; display: flex; flex-direction: column; gap: 5px; }

/* Code block inside article */
.sol-field-code { gap: 0; }
.sol-code-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 7px 14px; background: var(--off);
  border: 1px solid var(--dim); border-bottom: none;
}
.sol-code-editor {
  width: 100%; min-height: 380px; padding: 14px 16px;
  font-family: var(--font-body); font-size: 12.5px; line-height: 1.75;
  background: var(--white); border: 1px solid var(--dim);
  color: var(--black); resize: vertical; outline: none;
  tab-size: 2; caret-color: var(--black);
  transition: border-color 0.15s;
}
.sol-code-editor:focus { border-color: var(--black); }
.sol-code-editor::placeholder { color: var(--dim); font-style: italic; }

.sol-field-lang { flex-direction: column; gap: 6px; }


/* ════════════════════════════════════════════════════════════
   MOBILE — TRACKER & MODAL  (≤ 768px)
════════════════════════════════════════════════════════════ */
@media (max-width: 768px) {

  /* ── Nav ── */
  nav { padding: 0 14px; }
  .nav-logo { font-size: 12px; }
  .nav-links a { padding: 0 12px; font-size: 10px; }
  .sol-indicator { display: none; }

  /* ── Tracker layout: no sidebar, full width ── */
  .sidebar { display: none; }
  .tracker-main { margin-left: 0; }
  .tracker-topbar { padding: 14px 16px; }
  .tracker-topbar h1 { font-size: 15px; }
  .tb-right { display: none; }

  /* ── Topic group header ── */
  .t-group-hdr { padding: 10px 16px; }
  .t-group-hdr h3 { font-size: 11px; }

  /* ── Problem rows — tighter, 2-col grid on small screens ── */
  .p-row {
    grid-template-columns: 36px 1fr 28px 70px 32px;
    padding: 0 12px;
    height: 48px;
  }
  .p-row:hover { padding-left: 16px; }
  .p-num { font-size: 11px; }
  .p-name { font-size: 12px; }
  .p-diff-badge { font-size: 9px; padding: 3px 7px; }

  /* ── Modal overlay: full screen ── */
  .modal-overlay { padding: 0; align-items: flex-end; }
  .modal-box {
    max-width: 100%;
    height: 96vh;
    max-height: 96vh;
    border-radius: 16px 16px 0 0;
    transform: translateY(100%);
    transition: transform 0.35s cubic-bezier(0.25,0.46,0.45,0.94);
  }
  .modal-overlay.open .modal-box { transform: translateY(0); }

  /* ── Modal head ── */
  .modal-head { padding: 14px 16px 12px; gap: 10px; flex-wrap: wrap; }
  .modal-head-title { font-size: 17px; }
  .modal-head-num { font-size: 8px; }
  .leetcode-btn { font-size: 9px; padding: 5px 9px; }
  .modal-close { padding: 7px 12px; font-size: 15px; }

  /* ── Modal body: single column, tabs on top ── */
  .modal-body {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    overflow: hidden;
  }

  /* Problem info collapses to a compact scrollable panel */
  .modal-left {
    border-right: none;
    border-bottom: 1px solid var(--dim);
    max-height: 38vh;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    flex-shrink: 0;
  }

  .modal-section-desc { padding: 14px 16px 12px; }
  .prob-description { font-size: 12.5px; line-height: 1.7; }
  .modal-section-examples { padding: 12px 16px; }
  .prob-example { font-size: 11px; padding: 10px 12px; }
  .modal-section-constraints { padding: 12px 16px 14px; }
  .constraints { font-size: 11px; }

  /* Solution right panel fills remaining space */
  .modal-right {
    padding: 14px 14px 16px;
    gap: 10px;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    background: var(--paper);
  }

  /* ── Article solution writer ── */
  .sol-tabs-wrap {
    padding: 10px 14px 8px;
    gap: 6px;
    flex-wrap: wrap;
    align-items: flex-start;
  }
  .sol-approach-tab { font-size: 9px; padding: 5px 10px; }
  .sol-add-approach { font-size: 9px; padding: 5px 10px; }

  .sol-article { padding: 0; gap: 12px; }
  .sol-label { font-size: 8px; }
  .sol-input { font-size: 12px; padding: 9px 11px; }
  .sol-textarea { font-size: 12px; padding: 9px 11px; line-height: 1.65; }

  /* Code block full width, taller */
  .sol-code-editor { min-height: 180px; font-size: 12px; padding: 12px 12px; }
  .sol-code-header { padding: 6px 12px; }
  .editor-filename { font-size: 10px; }
  .editor-kb-hint { display: none; }

  /* Complexity row stacks vertically on very small */
  .sol-complexity-row { flex-direction: column; gap: 10px; }

  /* Lang tabs wrap nicely */
  .lang-tabs { flex-wrap: wrap; }
  .lang-tab { font-size: 9px; padding: 5px 10px; }

  /* ── Modal footer ── */
  .modal-foot {
    padding: 10px 14px;
    flex-wrap: wrap;
    gap: 8px;
  }
  .m-complete-wrap { padding: 5px 8px; }
  .m-complete-label { font-size: 10px; }
  .btn-cancel, .btn-save { padding: 8px 16px; font-size: 10px; }
  .save-msg { font-size: 9px; }

  /* ── Drag handle hint at top of modal sheet ── */
  .modal-box::before {
    content: '';
    display: block;
    width: 36px; height: 4px;
    background: var(--dim);
    border-radius: 2px;
    margin: 10px auto 0;
    flex-shrink: 0;
  }
}

/* ════════════════════════════════════════════════════════════
   MOBILE — very small phones (≤ 390px)
════════════════════════════════════════════════════════════ */
@media (max-width: 390px) {
  .modal-left { max-height: 32vh; }
  .p-row { grid-template-columns: 28px 1fr 24px 58px 28px; padding: 0 10px; height: 44px; }
  .p-name { font-size: 11px; }
  .p-diff-badge { font-size: 8px; padding: 2px 5px; }
  .modal-head-title { font-size: 15px; }
}

/* ════════════════════════════════════════════════════════════
   MOBILE FILTER BAR — search + difficulty, shown only on mobile
════════════════════════════════════════════════════════════ */
.mob-filterbar {
  display: none; /* hidden on desktop */
}
@media (max-width: 768px) {
  .mob-filterbar {
    display: flex;
    flex-direction: column;
    gap: 0;
    position: sticky;
    top: 52px;
    z-index: 90;
    background: var(--white);
    border-bottom: 1px solid var(--dim);
    box-shadow: 0 2px 8px rgba(10,10,10,0.06);
  }
  .mob-filterbar input {
    width: 100%; padding: 11px 14px;
    font-family: var(--font-body); font-size: 13px;
    background: var(--off); border: none;
    border-bottom: 1px solid var(--dim);
    color: var(--black); outline: none;
  }
  .mob-filterbar input::placeholder { color: var(--mid); }
  .mob-filterbar input:focus { background: var(--white); }
  .mob-filters {
    display: flex;
  }
  .mob-filters .sf-btn {
    flex: 1; padding: 9px 0; font-size: 10px;
    border-radius: 0; border: none;
    border-right: 1px solid var(--dim);
    box-shadow: none;
  }
  .mob-filters .sf-btn:last-child { border-right: none; }
}

@media (max-width: 768px) {
  .hero-roadmap { overflow: visible; margin-left: -16px; margin-right: -16px; border-left: none; border-right: none; }
  .roadmap-header-inner { padding-left: 16px; }
}
/* ── Constraint items — one per line ── */
.constraint-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 5px 0;
  font-size: 12px;
  color: var(--soft);
  line-height: 1.6;
  border-bottom: 1px solid var(--dim);
}
.constraint-item:last-child { border-bottom: none; }
.constraint-item::before {
  content: '—';
  color: var(--mid);
  font-size: 10px;
  flex-shrink: 0;
}

/* ── Approach color accents ── */
/* Tab colors */
.sol-approach-tab.approach-c0 { border-bottom: 2px solid #3730a3; }
.sol-approach-tab.approach-c1 { border-bottom: 2px solid #0369a1; }
.sol-approach-tab.approach-c2 { border-bottom: 2px solid #15803d; }
.sol-approach-tab.approach-c3 { border-bottom: 2px solid #b45309; }
.sol-approach-tab.approach-c4 { border-bottom: 2px solid #be185d; }

.sol-approach-tab.approach-c0.active { background: #3730a3; color: #fff; border-color: #3730a3; }
.sol-approach-tab.approach-c1.active { background: #0369a1; color: #fff; border-color: #0369a1; }
.sol-approach-tab.approach-c2.active { background: #15803d; color: #fff; border-color: #15803d; }
.sol-approach-tab.approach-c3.active { background: #b45309; color: #fff; border-color: #b45309; }
.sol-approach-tab.approach-c4.active { background: #be185d; color: #fff; border-color: #be185d; }

/* Article panel left accent bar */
.sol-article { border-left: 3px solid transparent; padding-left: 12px; transition: border-color 0.2s; }
.sol-article.approach-c0 { border-left-color: #3730a3; }
.sol-article.approach-c1 { border-left-color: #0369a1; }
.sol-article.approach-c2 { border-left-color: #15803d; }
.sol-article.approach-c3 { border-left-color: #b45309; }
.sol-article.approach-c4 { border-left-color: #be185d; }

/* Code editor header accent matches approach color */
.sol-article.approach-c0 .sol-code-header { background: #2e2b6e; }
.sol-article.approach-c1 .sol-code-header { background: #0c3a56; }
.sol-article.approach-c2 .sol-code-header { background: #0f3d22; }
.sol-article.approach-c3 .sol-code-header { background: #4a2c00; }
.sol-article.approach-c4 .sol-code-header { background: #5c0d2e; }

/* filename + hint text is always white on dark header backgrounds */
.sol-article.approach-c0 .sol-code-header .editor-filename,
.sol-article.approach-c1 .sol-code-header .editor-filename,
.sol-article.approach-c2 .sol-code-header .editor-filename,
.sol-article.approach-c3 .sol-code-header .editor-filename,
.sol-article.approach-c4 .sol-code-header .editor-filename { color: rgba(255,255,255,0.9); }

.sol-article.approach-c0 .sol-code-header .editor-kb-hint,
.sol-article.approach-c1 .sol-code-header .editor-kb-hint,
.sol-article.approach-c2 .sol-code-header .editor-kb-hint,
.sol-article.approach-c3 .sol-code-header .editor-kb-hint,
.sol-article.approach-c4 .sol-code-header .editor-kb-hint { color: rgba(255,255,255,0.45); }

/* ── Left panel filler: complexity reference card ── */
.modal-left-filler {
  flex: 1;
  min-height: 160px;
  padding: 16px 26px 20px;
  background: var(--off);
  border-top: 1px solid var(--dim);
  display: flex;
  flex-direction: column;
  gap: 10px;
  overflow-y: auto;
}
.filler-label {
  font-size: 9px; letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--mid); font-weight: 700; margin-bottom: 2px;
}
.filler-table { display: flex; flex-direction: column; gap: 0; }
.filler-row {
  display: grid; grid-template-columns: 90px 1fr;
  padding: 6px 0;
  border-bottom: 1px solid var(--dim);
  font-size: 11px; line-height: 1.5;
  gap: 12px;
}
.filler-row:last-child { border-bottom: none; }
.filler-complexity {
  font-family: var(--font-body); font-weight: 700;
  color: var(--black); font-size: 11px;
}
.filler-desc { color: var(--mid); font-size: 11px; }
.filler-divider {
  height: 1px; background: var(--dim); margin: 4px 0;
}
.filler-heading {
  font-size: 9px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--mid); margin-top: 4px;
}

/* ── Approach label accent lines ── */
.sol-article.approach-c0 .sol-label { border-bottom-color: #3730a3; color: #3730a3; }
.sol-article.approach-c1 .sol-label { border-bottom-color: #0369a1; color: #0369a1; }
.sol-article.approach-c2 .sol-label { border-bottom-color: #15803d; color: #15803d; }
.sol-article.approach-c3 .sol-label { border-bottom-color: #b45309; color: #b45309; }
.sol-article.approach-c4 .sol-label { border-bottom-color: #be185d; color: #be185d; }