/* ============================================================
   ShellVerse · Apple-grade Design System
   ============================================================ */
:root {
  --bg: #000000;
  --bg-2: #0a0a0f;
  --bg-3: #111118;
  --card: rgba(255,255,255,.04);
  --card-border: rgba(255,255,255,.09);
  --text: #f5f5f7;
  --text-2: #a1a1aa;
  --text-3: #6b6b76;
  --accent: #2997ff;
  --accent-2: #7d7aff;
  --ok: #30d158;
  --warn: #ffd60a;
  --linux: #f2994a;
  --cmd: #56ccf2;
  --ps: #9b51e0;
  --std: #6fcf97;
  --radius: 22px;
  --radius-sm: 14px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC",
          "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --mono: "SF Mono", "Cascadia Code", Consolas, "JetBrains Mono", Menlo, monospace;
  --ease: cubic-bezier(.28,.11,.32,1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  line-height: 1.6;
}
::selection { background: rgba(41,151,255,.35); }

/* 滚动条 */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: #2c2c34; border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: #3d3d48; }

/* ============ 导航 ============ */
#nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  background: rgba(10,10,15,.72);
  border-bottom: 1px solid rgba(255,255,255,.06);
  transition: background .4s;
}
.nav-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 22px;
  height: 56px; display: flex; align-items: center; justify-content: space-between;
}
.logo { display: flex; align-items: center; gap: 9px; text-decoration: none; color: var(--text); }
.logo-mark {
  font-family: var(--mono); font-weight: 700; font-size: 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff; padding: 3px 8px; border-radius: 8px;
  box-shadow: 0 0 18px rgba(41,151,255,.45);
}
.logo-text { font-size: 17px; letter-spacing: .2px; }
.logo-text b { font-weight: 700; background: linear-gradient(90deg,#2997ff,#bf5af2); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-links a {
  color: var(--text-2); text-decoration: none; font-size: 13.5px;
  transition: color .25s; position: relative;
}
.nav-links a:hover, .nav-links a.active { color: var(--text); }
.nav-progress { display: flex; align-items: center; gap: 7px; font-variant-numeric: tabular-nums; }
.mini-ring { width: 22px; height: 22px; transform: rotate(-90deg); }
.mini-ring circle { fill: none; stroke-width: 3.4; }
.mini-ring-bg { stroke: rgba(255,255,255,.12); }
.mini-ring-fg {
  stroke: var(--accent); stroke-linecap: round;
  stroke-dasharray: 100; stroke-dashoffset: 100;
  transition: stroke-dashoffset .8s var(--ease);
}
#navToggle { display: none; background: none; border: 0; cursor: pointer; padding: 6px; }
#navToggle span { display: block; width: 20px; height: 2px; background: var(--text); margin: 4px 0; border-radius: 2px; }

/* ============ Hero ============ */
.hero {
  position: relative; min-height: 100vh;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  text-align: center; padding: 120px 24px 80px; overflow: hidden;
}
.aurora { position: absolute; inset: 0; pointer-events: none; }
.aurora .blob {
  position: absolute; border-radius: 50%; filter: blur(110px); opacity: .5;
  animation: drift 18s ease-in-out infinite alternate;
}
.blob.b1 { width: 55vw; height: 55vw; background: radial-gradient(circle,#123a8f,transparent 65%); top: -20%; left: -10%; }
.blob.b2 { width: 45vw; height: 45vw; background: radial-gradient(circle,#5b21b6,transparent 65%); bottom: -15%; right: -8%; animation-delay: -6s; }
.blob.b3 { width: 35vw; height: 35vw; background: radial-gradient(circle,#0e5a4e,transparent 65%); top: 35%; left: 55%; animation-delay: -12s; }
@keyframes drift {
  from { transform: translate(0,0) scale(1); }
  to   { transform: translate(6vw,-4vh) scale(1.15); }
}
.hero-grid {
  position: absolute; inset: 0; pointer-events: none; opacity: .5;
  background-image:
    linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, #000 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, #000 30%, transparent 75%);
}
.hero-kicker {
  position: relative; font-size: 14px; letter-spacing: 3.5px; text-transform: uppercase;
  color: var(--accent); font-weight: 600; margin-bottom: 22px;
  animation: fadeUp 1s var(--ease) both;
}
.hero h1 {
  position: relative; font-size: clamp(44px, 8.5vw, 96px); font-weight: 700;
  line-height: 1.06; letter-spacing: -.02em;
  animation: fadeUp 1s var(--ease) .12s both;
}
.hero h1 .grad {
  background: linear-gradient(92deg,#2997ff 0%,#7d7aff 35%,#bf5af2 65%,#ff6482 100%);
  background-size: 200% 100%;
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
  animation: shine 6s linear infinite;
}
@keyframes shine { to { background-position: 200% center; } }
.hero-sub {
  position: relative; margin-top: 26px; font-size: clamp(16px, 2.2vw, 21px);
  color: var(--text-2); max-width: 640px;
  animation: fadeUp 1s var(--ease) .24s both;
}
.hero-cta { position: relative; margin-top: 42px; display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; animation: fadeUp 1s var(--ease) .36s both; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 30px; border-radius: 980px; font-size: 16px; font-weight: 500;
  text-decoration: none; cursor: pointer; border: 0; font-family: var(--font);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease), background .3s;
}
.btn-primary {
  background: var(--accent); color: #fff;
  box-shadow: 0 8px 30px rgba(41,151,255,.4);
}
.btn-primary:hover { transform: scale(1.045); box-shadow: 0 10px 42px rgba(41,151,255,.55); background: #2f9fff; }
.btn-ghost { background: rgba(255,255,255,.07); color: var(--text); border: 1px solid rgba(255,255,255,.14); }
.btn-ghost:hover { background: rgba(255,255,255,.12); transform: scale(1.045); }
@keyframes fadeUp { from { opacity: 0; transform: translateY(28px); } to { opacity: 1; transform: none; } }

/* 打字机终端 */
.hero-terminal {
  position: relative; margin-top: 60px; width: min(680px, 92vw);
  background: rgba(16,16,22,.82); border: 1px solid rgba(255,255,255,.1);
  border-radius: 16px; overflow: hidden; text-align: left;
  box-shadow: 0 30px 80px rgba(0,0,0,.6), 0 0 0 1px rgba(255,255,255,.04) inset;
  animation: fadeUp 1s var(--ease) .5s both;
}
.term-bar { display: flex; gap: 8px; padding: 13px 16px; background: rgba(255,255,255,.04); border-bottom: 1px solid rgba(255,255,255,.06); }
.term-dot { width: 12px; height: 12px; border-radius: 50%; }
.term-dot.r { background: #ff5f57; } .term-dot.y { background: #febc2e; } .term-dot.g { background: #28c840; }
.term-body { padding: 18px 22px; font-family: var(--mono); font-size: 14.5px; min-height: 132px; line-height: 1.9; }
.term-line { white-space: pre-wrap; word-break: break-all; }
.term-prompt { color: var(--ok); }
.term-cmd { color: #e8e8ee; }
.term-out { color: var(--text-3); }
.caret { display: inline-block; width: 8px; height: 17px; background: var(--ok); vertical-align: -3px; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

.scroll-hint {
  position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%);
  color: var(--text-3); font-size: 12px; letter-spacing: 2px;
  animation: bob 2.2s ease-in-out infinite;
}
@keyframes bob { 0%,100% { transform: translate(-50%,0); } 50% { transform: translate(-50%,8px); } }

/* ============ 通用 Section ============ */
.section { max-width: 1200px; margin: 0 auto; padding: 100px 24px; }
.section-head { text-align: center; margin-bottom: 64px; }
.section-kicker { color: var(--accent); font-size: 14px; font-weight: 600; letter-spacing: 2.5px; text-transform: uppercase; }
.section-title { font-size: clamp(30px, 4.6vw, 52px); font-weight: 700; letter-spacing: -.02em; margin-top: 10px; }
.section-desc { color: var(--text-2); font-size: 17px; max-width: 620px; margin: 16px auto 0; }

/* 滚动显现 */
.reveal { opacity: 0; transform: translateY(34px); transition: opacity .9s var(--ease), transform .9s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
.reveal.d1 { transition-delay: .1s; } .reveal.d2 { transition-delay: .2s; }
.reveal.d3 { transition-delay: .3s; } .reveal.d4 { transition-delay: .4s; }

/* ============ 板块卡片 ============ */
.tracks-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 22px; }
.track-card {
  position: relative; display: block; text-decoration: none; color: var(--text);
  background: var(--card); border: 1px solid var(--card-border);
  border-radius: var(--radius); padding: 34px 30px; overflow: hidden;
  transition: transform .45s var(--ease), border-color .45s, box-shadow .45s;
}
.track-card::before {
  content: ""; position: absolute; inset: 0; opacity: 0; transition: opacity .5s;
  background: radial-gradient(420px circle at var(--mx,50%) var(--my,0%), rgba(255,255,255,.09), transparent 45%);
}
.track-card:hover { transform: translateY(-8px); border-color: rgba(255,255,255,.2); box-shadow: 0 24px 60px rgba(0,0,0,.5); }
.track-card:hover::before { opacity: 1; }
.track-icon { font-size: 40px; display: block; margin-bottom: 18px; }
.track-name { font-size: 22px; font-weight: 700; }
.track-sub { color: var(--text-2); font-size: 13.5px; margin-top: 3px; }
.track-desc { color: var(--text-2); font-size: 14px; margin-top: 14px; min-height: 63px; }
.track-meta { display: flex; align-items: center; justify-content: space-between; margin-top: 20px; font-size: 13px; color: var(--text-3); }
.track-bar { height: 5px; background: rgba(255,255,255,.08); border-radius: 3px; overflow: hidden; margin-top: 12px; }
.track-bar i { display: block; height: 100%; border-radius: 3px; width: 0; transition: width 1.1s var(--ease); }
.track-go { color: var(--accent); font-weight: 600; }

/* ============ 学习路径时间线 ============ */
.path-wrap { position: relative; max-width: 760px; margin: 0 auto; }
.path-line {
  position: absolute; left: 29px; top: 10px; bottom: 10px; width: 2px;
  background: linear-gradient(180deg, var(--linux), var(--cmd), var(--ps), var(--std));
  border-radius: 2px; opacity: .55;
}
.path-item { position: relative; display: flex; gap: 26px; padding: 22px 0; }
.path-dot {
  flex: 0 0 60px; height: 60px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-weight: 700; font-size: 15px;
  background: var(--bg-3); border: 1px solid var(--card-border); z-index: 1;
}
.path-item.done .path-dot { background: linear-gradient(135deg,#30d158,#219653); border-color: transparent; box-shadow: 0 0 24px rgba(48,209,88,.4); }
.path-body { padding-top: 4px; }
.path-title { font-size: 19px; font-weight: 650; }
.path-item.done .path-title { color: var(--ok); }
.path-desc { color: var(--text-2); font-size: 14.5px; margin-top: 3px; }

/* ============ 章节列表页 ============ */
.track-hero { text-align: center; padding: 150px 24px 60px; position: relative; overflow: hidden; }
.track-hero .glow { position: absolute; top: -120px; left: 50%; transform: translateX(-50%); width: 640px; height: 380px; border-radius: 50%; filter: blur(120px); opacity: .35; pointer-events: none; }
.track-hero-icon { font-size: 64px; }
.track-hero h1 { font-size: clamp(36px, 6vw, 64px); font-weight: 700; letter-spacing: -.02em; margin-top: 14px; }
.track-hero p { color: var(--text-2); font-size: 18px; margin-top: 12px; }
.chapter-list { max-width: 860px; margin: 0 auto; padding: 20px 24px 120px; display: flex; flex-direction: column; gap: 16px; }
.chapter-item {
  display: flex; align-items: center; gap: 22px; text-decoration: none; color: var(--text);
  background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius);
  padding: 26px 30px; transition: transform .35s var(--ease), border-color .35s;
}
.chapter-item:hover { transform: translateX(8px); border-color: rgba(255,255,255,.22); }
.chapter-no {
  flex: 0 0 52px; height: 52px; border-radius: 16px; display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 18px; font-weight: 700;
}
.chapter-info { flex: 1; }
.chapter-title { font-size: 18.5px; font-weight: 650; }
.chapter-sub { color: var(--text-2); font-size: 13.5px; margin-top: 2px; }
.chapter-state { flex: 0 0 auto; font-size: 13px; color: var(--text-3); display: flex; align-items: center; gap: 8px; }
.chapter-state .badge-done { color: var(--ok); font-weight: 600; }
.state-ring { width: 26px; height: 26px; }

/* ============ 章节详情页 ============ */
.chapter-layout { max-width: 1200px; margin: 0 auto; padding: 110px 24px 100px; display: grid; grid-template-columns: 240px 1fr; gap: 48px; align-items: start; }
.toc { position: sticky; top: 90px; }
.toc-label { font-size: 12px; letter-spacing: 2px; color: var(--text-3); text-transform: uppercase; margin-bottom: 14px; }
.toc a {
  display: flex; align-items: center; gap: 10px; padding: 9px 12px; margin-bottom: 4px;
  color: var(--text-2); text-decoration: none; font-size: 13.5px; border-radius: 10px;
  border-left: 2px solid transparent; transition: all .25s;
}
.toc a:hover { color: var(--text); background: rgba(255,255,255,.05); }
.toc a.current { color: var(--text); background: rgba(255,255,255,.07); border-left-color: var(--accent); }
.toc a .toc-check { margin-left: auto; color: var(--ok); font-size: 12px; }

.chapter-content { min-width: 0; }
.chapter-head { margin-bottom: 44px; }
.chapter-crumb { font-size: 13px; color: var(--text-3); margin-bottom: 14px; }
.chapter-crumb a { color: var(--accent); text-decoration: none; }
.chapter-head h1 { font-size: clamp(30px, 4.6vw, 48px); font-weight: 700; letter-spacing: -.02em; }
.chapter-head .chapter-sub2 { color: var(--text-2); font-size: 17px; margin-top: 8px; }
.chapter-meta { display: flex; gap: 14px; margin-top: 16px; font-size: 13px; color: var(--text-3); align-items: center; flex-wrap: wrap; }
.chapter-meta .pill { background: rgba(255,255,255,.06); padding: 4px 12px; border-radius: 980px; }

.section-block { margin-bottom: 52px; }
.section-block h2 {
  font-size: 24px; font-weight: 700; margin-bottom: 16px;
  display: flex; align-items: center; gap: 12px;
}
.section-block h2::before {
  content: ""; width: 4px; height: 24px; border-radius: 2px;
  background: linear-gradient(180deg, var(--accent), var(--accent-2));
}
.section-block p { color: #c9c9d1; font-size: 15.5px; line-height: 1.85; margin-bottom: 16px; }
.section-block p b, .section-block p strong { color: var(--text); }

/* 代码块 */
.code-block {
  position: relative; background: #101016; border: 1px solid rgba(255,255,255,.08);
  border-radius: var(--radius-sm); overflow: hidden; margin-top: 14px;
}
.code-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 16px; background: rgba(255,255,255,.03); border-bottom: 1px solid rgba(255,255,255,.06);
  font-size: 11.5px; color: var(--text-3); font-family: var(--mono); letter-spacing: 1px;
}
.copy-btn {
  background: none; border: 0; color: var(--text-3); cursor: pointer; font-size: 12px;
  font-family: var(--font); padding: 3px 10px; border-radius: 6px; transition: all .25s;
}
.copy-btn:hover { color: var(--text); background: rgba(255,255,255,.08); }
.code-block pre { padding: 16px 20px; overflow-x: auto; font-family: var(--mono); font-size: 13.5px; line-height: 1.75; }
.code-block code { color: #d6deeb; }
.tok-c { color: #5c6370; font-style: italic; }  /* 注释 */
.tok-s { color: #c3e88d; }                      /* 字符串 */
.tok-k { color: #82aaff; }                      /* 关键字 */
.tok-v { color: #f78c6c; }                      /* 变量 */
.tok-n { color: #ffcb6b; }                      /* 数字 */

/* 练习题 */
.exercises-head {
  margin: 70px 0 26px; padding-top: 40px; border-top: 1px solid rgba(255,255,255,.08);
}
.exercises-head h2 { font-size: 28px; font-weight: 700; }
.exercises-head p { color: var(--text-2); margin-top: 8px; font-size: 15px; }
.ex-card {
  background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius);
  padding: 26px 28px; margin-bottom: 18px; transition: border-color .4s, box-shadow .4s;
}
.ex-card.solved { border-color: rgba(48,209,88,.45); box-shadow: 0 0 40px rgba(48,209,88,.08); }
.ex-q { display: flex; gap: 12px; font-size: 15.5px; line-height: 1.7; }
.ex-num {
  flex: 0 0 28px; height: 28px; border-radius: 8px; font-size: 13px; font-weight: 700;
  background: rgba(41,151,255,.15); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
}
.ex-card.solved .ex-num { background: rgba(48,209,88,.18); color: var(--ok); }
.ex-input-row { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.ex-input {
  flex: 1; min-width: 220px; background: #0c0c12; border: 1px solid rgba(255,255,255,.12);
  border-radius: 10px; padding: 11px 15px; color: var(--text); font-family: var(--mono);
  font-size: 14px; outline: none; transition: border-color .25s, box-shadow .25s;
}
.ex-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(41,151,255,.18); }
.ex-input.ok { border-color: var(--ok); }
.ex-input.bad { border-color: #ff453a; animation: shake .4s; }
@keyframes shake { 0%,100%{transform:translateX(0)} 25%{transform:translateX(-6px)} 75%{transform:translateX(6px)} }
.ex-btn {
  padding: 11px 22px; border-radius: 10px; border: 0; cursor: pointer;
  font-family: var(--font); font-size: 14px; font-weight: 550; transition: all .25s;
}
.ex-btn.check { background: var(--accent); color: #fff; }
.ex-btn.check:hover { background: #2f9fff; }
.ex-btn.hint, .ex-btn.show { background: rgba(255,255,255,.07); color: var(--text-2); }
.ex-btn.hint:hover, .ex-btn.show:hover { color: var(--text); background: rgba(255,255,255,.12); }
.ex-feedback { margin-top: 12px; font-size: 14px; min-height: 20px; }
.ex-feedback.ok { color: var(--ok); }
.ex-feedback.bad { color: #ff6961; }
.ex-hint-text, .ex-answer-text { margin-top: 10px; font-size: 13.5px; color: var(--warn); font-family: var(--mono); }
.ex-answer-text { color: var(--text-2); }
.ex-answer-text code { background: rgba(255,255,255,.07); padding: 3px 9px; border-radius: 6px; color: #c3e88d; }

/* 章节操作 */
.chapter-actions {
  display: flex; gap: 14px; margin-top: 60px; padding-top: 36px;
  border-top: 1px solid rgba(255,255,255,.08); flex-wrap: wrap; align-items: center;
}
.done-btn { display: inline-flex; align-items: center; gap: 9px; }
.done-btn.is-done { background: rgba(48,209,88,.15); color: var(--ok); border: 1px solid rgba(48,209,88,.4); }
.next-link { margin-left: auto; color: var(--accent); text-decoration: none; font-size: 15px; font-weight: 600; }
.next-link:hover { text-decoration: underline; }

/* ============ 进度仪表盘 ============ */
.progress-page { max-width: 1100px; margin: 0 auto; padding: 130px 24px 100px; }
.progress-top { display: grid; grid-template-columns: 300px 1fr; gap: 50px; align-items: center; margin-bottom: 70px; }
.big-ring-wrap { position: relative; width: 280px; height: 280px; margin: 0 auto; }
.big-ring { width: 100%; height: 100%; transform: rotate(-90deg); }
.big-ring circle { fill: none; stroke-width: 9; }
.big-ring .rbg { stroke: rgba(255,255,255,.07); }
.big-ring .rfg {
  stroke: url(#ringGrad); stroke-linecap: round;
  transition: stroke-dashoffset 1.4s var(--ease);
}
.ring-center { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
.ring-pct { font-size: 58px; font-weight: 700; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }
.ring-label { color: var(--text-2); font-size: 14px; margin-top: 2px; }
.progress-stats h1 { font-size: clamp(30px,4.6vw,46px); font-weight: 700; letter-spacing: -.02em; }
.progress-stats .sub { color: var(--text-2); margin-top: 10px; font-size: 16px; }
.stat-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px,1fr)); gap: 14px; margin-top: 28px; }
.stat-card { background: var(--card); border: 1px solid var(--card-border); border-radius: var(--radius-sm); padding: 18px 20px; }
.stat-num { font-size: 30px; font-weight: 700; font-variant-numeric: tabular-nums; }
.stat-num.c-ok { color: var(--ok); } .stat-num.c-blue { color: var(--accent); } .stat-num.c-warn { color: var(--warn); }
.stat-label { color: var(--text-3); font-size: 12.5px; margin-top: 2px; }

.map-title { font-size: 22px; font-weight: 700; margin: 60px 0 20px; }
.track-progress-row { margin-bottom: 30px; }
.track-progress-head { display: flex; justify-content: space-between; font-size: 14.5px; margin-bottom: 9px; }
.track-progress-head .t-name { font-weight: 650; }
.track-progress-head .t-pct { color: var(--text-2); font-variant-numeric: tabular-nums; }
.tp-bar { height: 8px; background: rgba(255,255,255,.07); border-radius: 4px; overflow: hidden; }
.tp-bar i { display: block; height: 100%; width: 0; border-radius: 4px; transition: width 1.2s var(--ease); }
.chapter-dots { display: flex; gap: 9px; margin-top: 13px; flex-wrap: wrap; }
.chapter-dot {
  width: 34px; height: 34px; border-radius: 10px; display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 12px; font-weight: 700; text-decoration: none;
  background: rgba(255,255,255,.05); color: var(--text-3); border: 1px solid rgba(255,255,255,.08);
  transition: transform .3s var(--ease), box-shadow .3s;
}
.chapter-dot:hover { transform: translateY(-4px) scale(1.08); }
.chapter-dot.lit { color: #fff; border-color: transparent; }
.reset-btn { margin-top: 60px; background: none; border: 1px solid rgba(255,69,58,.4); color: #ff6961; padding: 10px 22px; border-radius: 980px; cursor: pointer; font-size: 13.5px; transition: all .3s; font-family: var(--font); }
.reset-btn:hover { background: rgba(255,69,58,.12); }

/* ============ 页脚 ============ */
footer { border-top: 1px solid rgba(255,255,255,.07); padding: 48px 24px; }
.footer-inner { max-width: 1200px; margin: 0 auto; text-align: center; }
.footer-brand { font-size: 17px; font-weight: 600; display: flex; align-items: center; justify-content: center; gap: 9px; }
.footer-tip { color: var(--text-3); font-size: 13px; margin-top: 12px; }
.footer-copyright { color: #3f3f48; font-size: 12px; margin-top: 6px; }

/* 彩带 & Toast */
#confettiCanvas { position: fixed; inset: 0; pointer-events: none; z-index: 200; }
#toast {
  position: fixed; bottom: 34px; left: 50%; transform: translate(-50%, 80px);
  background: rgba(28,28,34,.92); border: 1px solid rgba(255,255,255,.14);
  color: var(--text); padding: 13px 26px; border-radius: 980px; font-size: 14.5px;
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  opacity: 0; transition: all .45s var(--ease); z-index: 210; pointer-events: none;
  box-shadow: 0 14px 40px rgba(0,0,0,.5);
}
#toast.show { opacity: 1; transform: translate(-50%, 0); }

/* 回到板块链接 */
.back-link { display: inline-flex; align-items: center; gap: 6px; color: var(--text-2); text-decoration: none; font-size: 14px; margin-bottom: 22px; transition: color .25s; }
.back-link:hover { color: var(--text); }

/* ============ 响应式 ============ */
@media (max-width: 900px) {
  .chapter-layout { grid-template-columns: 1fr; }
  .toc { position: static; display: flex; gap: 6px; overflow-x: auto; padding-bottom: 8px; }
  .toc-label { display: none; }
  .toc a { white-space: nowrap; border-left: 0; border: 1px solid rgba(255,255,255,.1); }
  .progress-top { grid-template-columns: 1fr; text-align: center; }
  .nav-links {
    position: fixed; top: 56px; left: 0; right: 0; flex-direction: column;
    background: rgba(10,10,15,.97); padding: 24px; gap: 20px;
    border-bottom: 1px solid rgba(255,255,255,.08);
    transform: translateY(-140%); transition: transform .4s var(--ease);
  }
  .nav-links.open { transform: none; }
  #navToggle { display: block; }
  .track-desc { min-height: 0; }
}