/* ============================================
   SHURAI — Global Stylesheet
   All pages import this file
   ============================================ */

:root {
  --bg: #070b14;
  --surface: #0d1320;
  --surface2: #131c2e;
  --surface3: #192236;
  --accent: #00d4ff;       /* cyan - Shur color */
  --accent2: #ff6b35;      /* orange - ai color */
  --accent3: #39ff6e;      /* green */
  --gold: #ffd166;
  --text: #e8f4f8;
  --muted: #6a8aaa;
  --border: rgba(0,212,255,0.12);
  --border2: rgba(0,212,255,0.22);
  --radius: 14px;
  --radius-lg: 20px;
}

/* ─── RESET ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Outfit', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
}
::selection { background: rgba(0,212,255,0.25); color: #fff; }
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--surface); }
::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }

/* ─── TYPOGRAPHY ─── */
h1, h2, h3, h4 { font-family: 'Outfit', sans-serif; line-height: 1.2; }
h1 { font-size: clamp(2.4rem, 6vw, 5rem); font-weight: 900; }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.8rem); font-weight: 800; margin-bottom: 14px; }
h3 { font-size: 1.1rem; font-weight: 700; color: var(--accent); margin: 26px 0 11px; }
p  { margin-bottom: 13px; line-height: 1.78; font-size: 0.95rem; color: #c5dce8; }
a  { color: var(--accent); text-decoration: none; transition: opacity 0.2s; }
a:hover { opacity: 0.8; }
code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  background: rgba(0,212,255,0.08);
  padding: 2px 7px;
  border-radius: 5px;
  color: var(--accent3);
}

/* ─── NAV ─── */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 999;
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 5vw;
  background: rgba(7,11,20,0.92);
  backdrop-filter: blur(22px);
  border-bottom: 1px solid var(--border);
}
.logo {
  font-family: 'Outfit', sans-serif;
  font-weight: 900; font-size: 1.5rem;
  text-decoration: none; letter-spacing: -0.02em;
}
.logo .shur { color: var(--accent); text-shadow: 0 0 20px rgba(0,212,255,0.4); }
.logo .ai   { color: var(--accent2); }
.nav-links { display: flex; gap: 1.8rem; list-style: none; align-items: center; }
.nav-links a {
  color: var(--muted); text-decoration: none;
  font-size: 0.9rem; font-weight: 500; transition: color 0.2s;
}
.nav-links a:hover, .nav-links a.active { color: var(--accent); opacity: 1; }
.nav-pill {
  background: linear-gradient(135deg, var(--accent), #0099cc);
  color: #000 !important; font-weight: 700 !important;
  padding: 8px 22px; border-radius: 50px; font-size: 0.85rem !important;
}
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; background: none; border: none;
}
.hamburger span { display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px; }

/* ─── BUTTONS ─── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 28px; border-radius: var(--radius);
  font-family: 'Outfit', sans-serif; font-weight: 600;
  font-size: 0.95rem; text-decoration: none; cursor: pointer;
  border: none; transition: all 0.25s;
}
.btn:hover { transform: translateY(-3px); opacity: 1; }
.btn-cyan {
  background: linear-gradient(135deg, var(--accent), #0099cc);
  color: #000; box-shadow: 0 8px 30px rgba(0,212,255,0.3);
}
.btn-cyan:hover { box-shadow: 0 14px 40px rgba(0,212,255,0.45); color: #000; }
.btn-ghost {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border2) !important; color: var(--text);
}
.btn-ghost:hover { background: rgba(0,212,255,0.08); border-color: var(--accent) !important; color: var(--text); }
.btn-sm { padding: 8px 18px; font-size: 0.85rem; border-radius: 9px; }

/* ─── SECTION COMMONS ─── */
section { padding: 90px 5vw; }
.sec-label {
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.2em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 10px;
  display: block;
}
.sec-sub { color: var(--muted); font-size: 1rem; max-width: 520px; margin-bottom: 50px; }
.surface-section { background: var(--surface); }

/* ─── CARDS ─── */
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 28px 24px;
  transition: all 0.3s;
}
.card:hover { border-color: var(--border2); transform: translateY(-4px); }

/* ─── TOPIC CARD ─── */
.topic-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px;
  cursor: pointer; transition: all 0.25s;
  display: flex; align-items: flex-start; gap: 14px;
  text-decoration: none;
}
.topic-card:hover {
  border-color: var(--accent); background: var(--surface2);
  transform: translateY(-3px); opacity: 1;
}
.topic-num {
  font-family: 'JetBrains Mono', monospace; font-size: 0.75rem;
  color: var(--accent); font-weight: 700; flex-shrink: 0;
  background: rgba(0,212,255,0.08); padding: 4px 8px; border-radius: 6px;
}
.topic-info h4 { font-size: 0.9rem; font-weight: 600; margin: 0 0 3px; line-height: 1.3; color: var(--text); }
.topic-info p  { color: var(--muted); font-size: 0.77rem; line-height: 1.4; margin: 0; }
.topic-badge {
  display: inline-block; padding: 2px 8px; border-radius: 50px;
  font-size: 0.68rem; font-weight: 700; margin-top: 6px;
}
.badge-basic { background: rgba(57,255,110,0.12); color: var(--accent3); }
.badge-inter { background: rgba(255,209,102,0.12); color: var(--gold); }
.badge-adv   { background: rgba(255,107,53,0.12); color: var(--accent2); }
.badge-coming { background: rgba(106,106,106,0.15); color: var(--muted); }

/* ─── CODE BLOCKS ─── */
.code-block {
  background: #080e1a; border: 1px solid rgba(0,212,255,0.14);
  border-radius: var(--radius); margin: 16px 0; overflow: hidden;
}
.code-header {
  display: flex; justify-content: space-between; align-items: center;
  padding: 9px 16px; background: rgba(0,212,255,0.05);
  border-bottom: 1px solid rgba(0,212,255,0.1);
}
.code-lang { font-family: 'JetBrains Mono', monospace; font-size: 0.7rem; color: var(--accent); font-weight: 700; }
.copy-btn {
  font-size: 0.7rem; color: var(--muted); background: none; border: none;
  cursor: pointer; font-family: 'Outfit', sans-serif; padding: 3px 8px;
  border-radius: 5px; transition: all 0.2s;
}
.copy-btn:hover { color: var(--accent); background: rgba(0,212,255,0.1); }
pre { margin: 0; padding: 18px 20px; overflow-x: auto; }
pre code {
  font-family: 'JetBrains Mono', monospace; font-size: 0.84rem;
  line-height: 1.72; color: #d0f0ff; background: none; padding: 0;
  border-radius: 0;
}

/* Syntax highlight */
.kw { color: #ff79c6; }
.fn { color: #50fa7b; }
.st { color: #f1fa8c; }
.cm { color: #5a6a8a; font-style: italic; }
.nm { color: #bd93f9; }
.op { color: #ff6b35; }
.bl { color: #8be9fd; }

/* ─── INFO / WARN BOXES ─── */
.info-box {
  background: rgba(0,212,255,0.05); border: 1px solid rgba(0,212,255,0.14);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 15px 20px; margin: 15px 0;
}
.warn-box {
  background: rgba(255,209,102,0.05); border: 1px solid rgba(255,209,102,0.14);
  border-left: 3px solid var(--gold);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 15px 20px; margin: 15px 0;
}
.info-box p, .warn-box p { margin: 0; font-size: 0.88rem; }
.info-box strong { display: block; margin-bottom: 4px; font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--accent); }
.warn-box strong { display: block; margin-bottom: 4px; font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--gold); }

/* ─── QUOTE INLINE ─── */
.quote-inline {
  background: rgba(255,107,53,0.05); border: 1px solid rgba(255,107,53,0.14);
  border-radius: var(--radius); padding: 18px 22px; margin: 20px 0;
  text-align: center;
}
.quote-inline p { font-size: 0.98rem; font-style: italic; color: var(--text); margin: 0 0 5px; }
.quote-inline cite { font-size: 0.76rem; color: var(--accent2); font-weight: 700; font-style: normal; }

/* ─── LESSON LAYOUT ─── */
.lesson-wrap { max-width: 1180px; margin: 0 auto; padding: 100px 5vw 60px; }
.lesson-layout { display: grid; grid-template-columns: 260px 1fr; gap: 28px; }
.lesson-sidebar {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px;
  height: fit-content; position: sticky; top: 90px;
}
.lesson-sidebar h3 {
  font-size: 0.78rem; font-weight: 700; color: var(--muted);
  text-transform: uppercase; letter-spacing: 0.1em;
  margin: 0 0 14px; color: var(--muted);
}
.sidebar-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: 10px;
  transition: all 0.2s; margin-bottom: 4px;
  font-size: 0.82rem; color: var(--muted);
  text-decoration: none;
}
.sidebar-item:hover { background: var(--surface2); color: var(--text); opacity: 1; }
.sidebar-item.active { background: rgba(0,212,255,0.1); color: var(--accent); font-weight: 600; }
.sidebar-num { font-family: 'JetBrains Mono', monospace; font-size: 0.7rem; color: var(--accent); min-width: 26px; }
.sidebar-done { color: var(--accent3); font-size: 0.75rem; margin-left: auto; }
.lesson-main {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 38px;
}

/* ─── LESSON NAV BAR ─── */
.lesson-topbar {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 26px; padding-bottom: 18px;
  border-bottom: 1px solid var(--border); flex-wrap: wrap; gap: 10px;
}
.breadcrumb { color: var(--muted); font-size: 0.8rem; }
.breadcrumb span { color: var(--accent); }
.lesson-nav-btns { display: flex; gap: 10px; flex-wrap: wrap; }
.lb {
  padding: 8px 18px; border-radius: 9px; border: 1px solid var(--border);
  background: transparent; color: var(--text); font-family: 'Outfit', sans-serif;
  font-size: 0.85rem; cursor: pointer; transition: all 0.2s; text-decoration: none;
  display: inline-flex; align-items: center; gap: 6px;
}
.lb:hover { border-color: var(--accent); color: var(--accent); opacity: 1; }
.lb.primary { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 700; }
.lb.primary:hover { background: #00b8dc; color: #000; }

/* ─── PROGRESS BAR ─── */
.progress-row { display: flex; justify-content: space-between; font-size: 0.76rem; color: var(--muted); margin-bottom: 5px; }
.prog-wrap { background: var(--surface2); border-radius: 50px; height: 5px; margin-bottom: 26px; overflow: hidden; }
.prog-bar { height: 100%; border-radius: 50px; background: linear-gradient(90deg, var(--accent), var(--accent3)); transition: width 0.4s ease; }

/* ─── LESSON HEADER ─── */
.lesson-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }
.l-tag { padding: 3px 10px; border-radius: 50px; font-size: 0.72rem; font-weight: 600; }
.tag-py  { background: rgba(57,255,110,0.1); color: var(--accent3); border: 1px solid rgba(57,255,110,0.2); }
.tag-lvl { background: rgba(0,212,255,0.1); color: var(--accent); border: 1px solid var(--border2); }
.tag-num { background: rgba(0,212,255,0.06); color: var(--muted); border: 1px solid var(--border); }
.lesson-title { font-weight: 800; font-size: 1.75rem; line-height: 1.2; margin-bottom: 8px; color: var(--text); }
.lesson-desc { color: var(--muted); font-size: 0.94rem; margin-bottom: 22px; }

/* ─── LESSON CONTENT ─── */
.lesson-content ul { margin: 0 0 15px 0; padding-left: 0; list-style: none; }
.lesson-content ul li { padding: 5px 0 5px 20px; position: relative; font-size: 0.92rem; color: #c5dce8; }
.lesson-content ul li::before { content: '▸'; position: absolute; left: 0; color: var(--accent); font-size: 0.78rem; top: 7px; }

/* ─── LESSON BOTTOM NAV ─── */
.lesson-footer {
  display: flex; justify-content: space-between;
  margin-top: 34px; padding-top: 22px;
  border-top: 1px solid var(--border); flex-wrap: wrap; gap: 12px;
}
.lesson-complete { color: var(--accent3); font-weight: 700; font-size: 0.95rem; display: flex; align-items: center; gap: 8px; }

/* ─── PROGRESS TRACKER (localStorage) ─── */
.mark-done-btn {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 22px; border-radius: 9px;
  border: 1px solid var(--accent3); background: transparent;
  color: var(--accent3); font-family: 'Outfit', sans-serif;
  font-size: 0.88rem; font-weight: 600; cursor: pointer;
  transition: all 0.2s; margin: 20px 0;
}
.mark-done-btn.done { background: rgba(57,255,110,0.1); }
.mark-done-btn:hover { background: rgba(57,255,110,0.1); }

/* ─── QUIZ ─── */
.quiz-block {
  background: var(--surface2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 26px; margin: 28px 0;
}
.quiz-block h4 { font-weight: 700; margin-bottom: 18px; color: var(--accent); font-size: 0.95rem; }
.quiz-q { font-size: 0.95rem; color: var(--text); margin-bottom: 16px; font-weight: 500; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.quiz-opt {
  padding: 11px 18px; border-radius: 9px; border: 1px solid var(--border);
  background: var(--surface); color: var(--text); cursor: pointer;
  font-family: 'Outfit', sans-serif; font-size: 0.88rem;
  text-align: left; transition: all 0.2s;
}
.quiz-opt:hover { border-color: var(--accent); background: rgba(0,212,255,0.05); }
.quiz-opt.correct { border-color: var(--accent3); background: rgba(57,255,110,0.1); color: var(--accent3); }
.quiz-opt.wrong   { border-color: #ff4444; background: rgba(255,68,68,0.1); color: #ff4444; }
.quiz-feedback { margin-top: 14px; font-size: 0.88rem; font-weight: 600; display: none; }
.quiz-feedback.show { display: block; }
.quiz-feedback.pass { color: var(--accent3); }
.quiz-feedback.fail { color: var(--accent2); }

/* ─── BOOKMARK ─── */
.bookmark-btn {
  background: none; border: 1px solid var(--border); border-radius: 9px;
  padding: 8px 14px; color: var(--muted); cursor: pointer;
  font-size: 1rem; transition: all 0.2s; display: inline-flex; align-items: center; gap: 6px;
  font-family: 'Outfit', sans-serif; font-size: 0.85rem;
}
.bookmark-btn:hover, .bookmark-btn.saved { border-color: var(--gold); color: var(--gold); background: rgba(255,209,102,0.08); }

/* ─── READ TIME ─── */
.read-time { color: var(--muted); font-size: 0.78rem; display: flex; align-items: center; gap: 5px; }

/* ─── COMING SOON LESSON ─── */
.coming-soon-box {
  text-align: center; padding: 60px 30px;
  background: var(--surface2); border: 1px dashed var(--border2);
  border-radius: var(--radius-lg); margin: 30px 0;
}
.coming-soon-box .big-icon { font-size: 4rem; margin-bottom: 20px; }
.coming-soon-box h3 { color: var(--text) !important; margin: 0 0 12px; font-size: 1.3rem; }
.coming-soon-box p { color: var(--muted); max-width: 400px; margin: 0 auto; }

/* ─── TOPICS GRID ─── */
.topics-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.topic-filters { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 28px; }
.filter-btn {
  padding: 7px 16px; border-radius: 50px; border: 1px solid var(--border);
  background: transparent; color: var(--muted); font-family: 'Outfit', sans-serif;
  font-size: 0.82rem; font-weight: 500; cursor: pointer; transition: all 0.2s;
}
.filter-btn:hover, .filter-btn.active { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 700; }

/* ─── QUOTE BAND ─── */
.quote-band {
  background: var(--surface); border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border); padding: 38px 5vw;
  text-align: center; position: relative; overflow: hidden;
}
.quote-band::before { content: ''; position: absolute; left: 0; top: 0; bottom: 0; width: 4px; background: linear-gradient(var(--accent), var(--accent2), var(--accent3)); }
.quote-band-text { font-size: 1.15rem; font-weight: 600; color: var(--text); max-width: 680px; margin: 0 auto 8px; line-height: 1.6; font-style: italic; }
.quote-band-author { color: var(--accent); font-size: 0.82rem; font-weight: 700; letter-spacing: 0.08em; }

/* ─── QUOTES MOSAIC ─── */
.quotes-mosaic { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; }
.qmc {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 24px;
  transition: transform 0.3s, border-color 0.3s; position: relative; overflow: hidden;
}
.qmc:hover { transform: translateY(-4px); border-color: var(--border2); }
.qmc::before { content: '"'; position: absolute; top: -10px; right: 16px; font-size: 6rem; color: rgba(0,212,255,0.05); font-family: 'Outfit', sans-serif; font-weight: 900; line-height: 1; }
.qmc-text  { font-size: 0.92rem; color: #c5dce8; line-height: 1.72; margin-bottom: 14px; font-style: italic; }
.qmc-author { font-size: 0.78rem; font-weight: 700; color: var(--accent); letter-spacing: 0.05em; }
.qmc-line  { position: absolute; bottom: 0; left: 0; right: 0; height: 2px; }

/* ─── FEATURES GRID ─── */
.feat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 20px; }
.feat-card {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 30px 24px;
  transition: all 0.3s; position: relative; overflow: hidden;
}
.feat-card::after { content: ''; position: absolute; bottom: 0; left: 0; right: 0; height: 2px; background: linear-gradient(90deg, var(--accent), var(--accent2)); transform: scaleX(0); transition: transform 0.3s; }
.feat-card:hover { transform: translateY(-5px); border-color: var(--border2); }
.feat-card:hover::after { transform: scaleX(1); }
.feat-icon { font-size: 2rem; margin-bottom: 16px; }
.feat-card h3 { font-weight: 700; font-size: 1rem; margin: 0 0 8px; color: var(--text); }
.feat-card p  { color: var(--muted); font-size: 0.88rem; line-height: 1.65; margin: 0; }

/* ─── FOOTER ─── */
footer {
  background: var(--surface); border-top: 1px solid var(--border);
  padding: 50px 5vw 28px;
}
.footer-top { display: flex; justify-content: space-between; align-items: flex-start; flex-wrap: wrap; gap: 30px; margin-bottom: 40px; }
.footer-brand p { color: var(--muted); font-size: 0.85rem; margin-top: 10px; max-width: 240px; }
.footer-col h4 { font-size: 0.8rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.1em; color: var(--muted); margin-bottom: 14px; }
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 9px; }
.footer-col ul li a { color: var(--muted); font-size: 0.85rem; transition: color 0.2s; }
.footer-col ul li a:hover { color: var(--accent); opacity: 1; }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 20px; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; color: var(--muted); font-size: 0.8rem; }

/* ─── ABOUT ─── */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.about-visual { aspect-ratio: 1; max-width: 380px; border-radius: 24px; background: linear-gradient(135deg, rgba(0,212,255,0.08), rgba(255,107,53,0.06)); border: 1px solid var(--border); display: flex; align-items: center; justify-content: center; font-size: 7rem; }
.mission-point { display: flex; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--border); }
.mission-point:last-child { border-bottom: none; }
.mp-icon { width: 36px; height: 36px; border-radius: 9px; background: rgba(0,212,255,0.1); border: 1px solid var(--border2); display: flex; align-items: center; justify-content: center; flex-shrink: 0; font-size: 1rem; }
.mp-text h4 { font-weight: 600; font-size: 0.9rem; margin-bottom: 3px; color: var(--text); }
.mp-text p  { color: var(--muted); font-size: 0.83rem; margin: 0; }

/* ─── REVEAL ANIMATION ─── */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ─── SEARCH BOX ─── */
.search-box {
  width: 100%; padding: 13px 20px; border-radius: var(--radius);
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); font-family: 'Outfit', sans-serif;
  font-size: 0.9rem; outline: none; transition: border-color 0.2s; margin-bottom: 18px;
}
.search-box:focus { border-color: var(--accent); }
.search-box::placeholder { color: var(--muted); }

/* ─── HERO ─── */
.hero { min-height: 100vh; display: flex; align-items: center; justify-content: center; text-align: center; padding: 120px 5vw 80px; position: relative; overflow: hidden; }
.hero-aurora { position: absolute; inset: 0; z-index: 0; background: radial-gradient(ellipse 70% 50% at 30% 20%, rgba(0,212,255,0.08), transparent 65%), radial-gradient(ellipse 60% 40% at 70% 70%, rgba(255,107,53,0.07), transparent 60%), radial-gradient(ellipse 50% 60% at 80% 10%, rgba(57,255,110,0.05), transparent 55%); animation: aurora 8s ease-in-out infinite alternate; }
@keyframes aurora { 0% { transform: scale(1); } 100% { transform: scale(1.04); } }
.hero-dots { position: absolute; inset: 0; z-index: 0; background-image: radial-gradient(rgba(0,212,255,0.06) 1px, transparent 1px); background-size: 32px 32px; }
.hero-content { position: relative; z-index: 1; max-width: 800px; }
.hero-chip { display: inline-flex; align-items: center; gap: 8px; background: rgba(0,212,255,0.08); border: 1px solid var(--border2); border-radius: 50px; padding: 6px 18px; font-size: 0.8rem; font-weight: 600; color: var(--accent); margin-bottom: 28px; }
.live-dot { width: 7px; height: 7px; background: var(--accent3); border-radius: 50%; animation: blink 1.5s infinite; }
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }
.hero h1 { margin-bottom: 20px; }
.shine { background: linear-gradient(135deg, var(--accent) 0%, #80eaff 40%, var(--accent2) 80%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-sub { font-size: 1.1rem; color: var(--muted); max-width: 540px; margin: 0 auto 40px; line-height: 1.8; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-stats { display: flex; gap: 36px; justify-content: center; margin-top: 70px; flex-wrap: wrap; }
.trail-stat { text-align: center; }
.trail-n { font-weight: 900; font-size: 2rem; color: var(--accent); text-shadow: 0 0 20px rgba(0,212,255,0.35); }
.trail-l { color: var(--muted); font-size: 0.8rem; font-weight: 500; margin-top: 2px; }

/* ─── RESPONSIVE ─── */
@media (max-width: 900px) {
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-sidebar { display: none; }
  .about-grid { grid-template-columns: 1fr; }
  .about-visual { display: none; }
}
@media (max-width: 600px) {
  .nav-links { display: none; flex-direction: column; position: fixed; top: 62px; left: 0; right: 0; background: var(--surface); padding: 20px 5vw; border-bottom: 1px solid var(--border); gap: 1rem; }
  .nav-links.open { display: flex; }
  .hamburger { display: flex; }
  .hero-stats { gap: 22px; }
  section { padding: 60px 5vw; }
  .lesson-main { padding: 22px; }
}

/* ─── LIGHT MODE ─── */

body.light {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --surface2: #eef1f6;
  --surface3: #e4e8f0;
  --text: #1a2233;
  --muted: #5a6a88;
  --border: rgba(0,100,180,0.12);
  --border2: rgba(0,100,180,0.22);
  background: #f5f7fa;
  color: #1a2233;
}

body.light nav {
  background: rgba(245,247,250,0.95);
}

body.light .surface-section,
body.light section {
  background: #f5f7fa;
}

body.light .qmc,
body.light .card,
body.light .feat-card,
body.light .topic-card,
body.light .lesson-main,
body.light .lesson-sidebar {
  background: #ffffff;
  border-color: rgba(0,100,180,0.12);
}

body.light .lesson-topbar,
body.light .footer-bottom {
  border-color: rgba(0,100,180,0.12);
}

body.light footer {
  background: #ffffff;
  border-color: rgba(0,100,180,0.12);
}

body.light h1,
body.light h2,
body.light h3,
body.light h4 {
  color: #1a2233;
}

body.light .qmc-text,
body.light .lesson-content p,
body.light .lc p {
  color: #334155;
}

body.light .info-box {
  background: rgba(0,100,180,0.05);
}

body.light .warn-box {
  background: rgba(200,140,0,0.05);
}

body.light .quote-inline {
  background: rgba(255,107,53,0.05);
}

body.light .prog-wrap {
  background: #e4e8f0;
}

body.light .quiz-block {
  background: #eef1f6;
}

body.light .quiz-opt {
  background: #ffffff;
  border-color: rgba(0,100,180,0.15);
  color: #1a2233;
}

body.light .hero-aurora {
  background:
    radial-gradient(ellipse 70% 50% at 30% 20%, rgba(0,150,255,0.08), transparent 65%),
    radial-gradient(ellipse 60% 40% at 70% 70%, rgba(255,107,53,0.06), transparent 60%);
}
body.light pre code { color: #1a2233; }
body.light .code-block { background: #f0f4fa; }
body.light .kw  { color: #d63384; }
body.light .fn  { color: #198754; }
body.light .st  { color: #856404; }
body.light .cm  { color: #6a8aaa; }
body.light .nm  { color: #6f42c1; }
body.light .bl  { color: #0d6efd; }

/* ─── THEME TOGGLE BUTTON ─── */
.theme-btn {
  background: none;
  border: 1px solid var(--border2);
  border-radius: 50px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--muted);
  font-family: 'Outfit', sans-serif;
  transition: all 0.2s;
  white-space: nowrap;
}
.theme-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}