/* Flutter Academy · Web —— 深色影院感 + 玻璃拟态；支持一键切换暖白亮色主题 */
:root {
  color-scheme: dark;

  /* 品牌 / 装饰色（两种主题共享） */
  --cyan: #00d2ff;
  --ice: #a4f4fd;
  --deep: #0b2551;
  --brand-blue: #54c5f8;
  --grape: #a78bfa;
  --rose: #fb7185;
  --green: #34d399;
  --amber: #f59e0b;

  /* —— 深色主题（默认）—— */
  --base: #0c0c0c;
  --panel: #0e1014;
  --panel-alt: #12151b;
  --panel-solid: rgba(26, 29, 35, 0.96);

  --fg-strong: #ffffff;
  --text-1: rgba(255, 255, 255, 0.95);
  --text-2: rgba(255, 255, 255, 0.62);
  --text-3: rgba(255, 255, 255, 0.40);
  --text-4: rgba(255, 255, 255, 0.22);
  --accent: #00d2ff;

  --border: rgba(255, 255, 255, 0.10);
  --border-strong: rgba(255, 255, 255, 0.16);
  --fill-soft: rgba(255, 255, 255, 0.04);
  --fill-hover: rgba(255, 255, 255, 0.07);
  --track: rgba(255, 255, 255, 0.10);
  --scroll: rgba(255, 255, 255, 0.12);

  --glass-bg: rgba(255, 255, 255, 0.02);
  --glass-top: rgba(255, 255, 255, 0.07);
  --topbar-bg: rgba(14, 16, 20, 0.55);
  --sidebar-bg: rgba(9, 10, 15, 0.5);
  --veil: rgba(12, 12, 12, 0.9);
  --overlay-bg: rgba(4, 6, 10, 0.6);
  --shadow: rgba(0, 0, 0, 0.55);

  --aur-op: 0.5;
  --aur1: rgba(0, 210, 255, 0.55);
  --aur2: rgba(167, 139, 250, 0.45);

  /* 代码面板恒为深色（两种主题一致，保证可读性） */
  --code-bg: #0e1014;
  --code-brd: rgba(255, 255, 255, 0.08);

  --font-ui: "Segoe UI Variable Text", "Segoe UI", "SF Pro Text", "Microsoft YaHei UI",
    "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  --font-display: "Segoe UI Variable Display", "Segoe UI", "SF Pro Display",
    "Microsoft YaHei UI", system-ui, sans-serif;
  --font-code: "Cascadia Code", "Cascadia Mono", Consolas, "SF Mono", Menlo,
    "DejaVu Sans Mono", monospace;

  --radius: 16px;
  --maxw: 780px;
  --sidebar-w: 264px;
}

/* —— 暖白亮色主题（偏浅色学习平台风格）—— */
html[data-theme="light"] {
  color-scheme: light;

  --base: #f5f1ea;          /* 暖白底 */
  --panel: #ffffff;
  --panel-alt: #f3efe7;
  --panel-solid: #ffffff;

  --fg-strong: #26221c;
  --text-1: rgba(38, 34, 28, 0.96);
  --text-2: rgba(52, 46, 38, 0.78);
  --text-3: rgba(52, 46, 38, 0.62);
  --text-4: rgba(52, 46, 38, 0.46);
  --accent: #0a7ea4;

  --border: rgba(60, 45, 25, 0.14);
  --border-strong: rgba(60, 45, 25, 0.22);
  --fill-soft: rgba(120, 95, 55, 0.06);
  --fill-hover: rgba(120, 95, 55, 0.11);
  --track: rgba(60, 45, 25, 0.14);
  --scroll: rgba(60, 45, 25, 0.22);

  --glass-bg: rgba(255, 255, 255, 0.66);
  --glass-top: rgba(255, 255, 255, 0.9);
  --topbar-bg: rgba(255, 252, 246, 0.72);
  --sidebar-bg: rgba(255, 252, 246, 0.6);
  --veil: rgba(245, 241, 234, 0.92);
  --overlay-bg: rgba(120, 100, 70, 0.24);
  --shadow: rgba(120, 95, 55, 0.20);

  --aur-op: 0.32;
  --aur1: rgba(0, 150, 200, 0.30);
  --aur2: rgba(167, 139, 250, 0.22);

  --cyan: #0a94c4;
  --ice: #2aa7cf;
  --brand-blue: #2f8fd0;
  --grape: #7b5bd6;
  --green: #12a06b;
  --amber: #c98a12;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--base);
  color: var(--text-1);
  font-family: var(--font-ui);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .35s ease, color .35s ease;
}

::selection { background: color-mix(in srgb, var(--accent) 32%, transparent); }

/* 动态极光背景 */
.aurora {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
  background: var(--base);
}
.aurora::before,
.aurora::after {
  content: "";
  position: absolute;
  width: 60vmax;
  height: 60vmax;
  border-radius: 50%;
  filter: blur(60px);
  opacity: var(--aur-op);
  animation: drift 24s ease-in-out infinite alternate;
}
.aurora::before {
  background: radial-gradient(circle, var(--aur1), transparent 62%);
  top: -22vmax;
  left: -12vmax;
}
.aurora::after {
  background: radial-gradient(circle, var(--aur2), transparent 62%);
  bottom: -26vmax;
  right: -14vmax;
  animation-duration: 30s;
}
.aurora .beacon {
  position: absolute;
  top: -30vmax;
  left: 50%;
  width: 80vmax;
  height: 80vmax;
  transform: translateX(-50%);
  border-radius: 50%;
  background: conic-gradient(from 0deg,
    color-mix(in srgb, var(--cyan) 18%, transparent),
    color-mix(in srgb, var(--grape) 10%, transparent),
    color-mix(in srgb, var(--ice) 20%, transparent),
    transparent,
    color-mix(in srgb, var(--cyan) 18%, transparent));
  filter: blur(40px);
  animation: spin 40s linear infinite;
}
@keyframes drift {
  0%   { transform: translate(0, 0) scale(1); }
  50%  { transform: translate(6vmax, 4vmax) scale(1.08); }
  100% { transform: translate(-4vmax, 6vmax) scale(0.96); }
}
@keyframes spin { to { transform: translateX(-50%) rotate(360deg); } }
body.reduce-motion .aurora::before,
body.reduce-motion .aurora::after,
body.reduce-motion .aurora .beacon { animation: none; }

/* 底部渐隐，保证前景对比度 */
.vignette {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(to bottom, transparent 30%, var(--shadow) 100%);
  opacity: .6;
}
html[data-theme="light"] .vignette { opacity: .25; }

/* 应用框架 */
.app {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  grid-template-rows: 52px 1fr;
  height: 100vh;
  height: 100dvh; /* 移动端动态视口高度，避开浏览器地址栏遮挡 */
}
.topbar {
  grid-column: 1 / 3;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  border-bottom: 1px solid var(--border);
  background: var(--topbar-bg);
  backdrop-filter: blur(14px);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 14px; color: var(--fg-strong); }
.brand .logo {
  width: 26px; height: 26px; border-radius: 8px;
  background: conic-gradient(from 210deg, var(--cyan), var(--grape), var(--ice), var(--cyan));
  box-shadow: 0 0 18px color-mix(in srgb, var(--cyan) 55%, transparent);
  position: relative;
}
.brand .logo::after {
  content: ""; position: absolute; inset: 6px; border-radius: 5px;
  background: var(--topbar-bg);
}
.spacer { flex: 1; }
.progress-chip {
  font-size: 12px; color: var(--text-2);
  padding: 5px 11px; border: 1px solid var(--border); border-radius: 100px;
  background: var(--fill-soft);
}

/* 主题切换按钮 */
.theme-btn {
  display: inline-grid; place-items: center;
  width: 34px; height: 34px; border-radius: 50%;
  border: 1px solid var(--border-strong); background: var(--fill-soft);
  color: var(--text-1); cursor: pointer; font-size: 16px;
  transition: background .18s, transform .3s, color .18s;
}
.theme-btn:hover { background: var(--fill-hover); transform: rotate(18deg) scale(1.06); }

/* 侧栏 */
.sidebar {
  border-right: 1px solid var(--border);
  background: var(--sidebar-bg);
  backdrop-filter: blur(14px);
  overflow-y: auto;
  padding: 14px 12px 40px;
}
.nav { display: flex; flex-direction: column; gap: 3px; margin-bottom: 16px; }
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: 11px;
  color: var(--text-2); cursor: pointer; font-size: 13px;
  border: 1px solid transparent; background: transparent;
  transition: background .16s, color .16s, border-color .16s;
  width: 100%; text-align: left; font-family: inherit;
}
.nav-item:hover { background: var(--fill-hover); color: var(--text-1); }
.nav-item.active {
  color: var(--fg-strong); font-weight: 700;
  border-color: color-mix(in srgb, var(--cyan) 40%, transparent);
  background: linear-gradient(90deg, color-mix(in srgb, var(--cyan) 22%, transparent), color-mix(in srgb, var(--cyan) 4%, transparent));
  box-shadow: 0 0 20px -6px color-mix(in srgb, var(--cyan) 55%, transparent);
}
.nav-item .ico { width: 18px; text-align: center; opacity: .9; }
.nav-item .badge { margin-left: auto; font-size: 10px; color: var(--text-3); }
.nav-item.active .badge { color: var(--accent); }

.toc-title {
  font-size: 10px; letter-spacing: 1.4px; text-transform: uppercase;
  color: var(--text-4); margin: 8px 6px 6px;
}
.toc-group { margin-bottom: 10px; }
.toc-group > .g-head {
  display: flex; align-items: center; gap: 8px; padding: 6px;
  font-size: 11.5px; font-weight: 600; color: var(--text-2); cursor: pointer;
}
.toc-group > .g-head .dot { width: 7px; height: 7px; border-radius: 50%; }
.toc-link {
  display: flex; align-items: center; gap: 8px;
  padding: 6px 8px 6px 20px; border-radius: 8px;
  font-size: 12.5px; color: var(--text-3); cursor: pointer;
  transition: background .14s, color .14s;
}
.toc-link:hover { background: var(--fill-hover); color: var(--text-1); }
.toc-link.active { color: var(--fg-strong); background: color-mix(in srgb, var(--cyan) 12%, transparent); }
.toc-link .chk { margin-left: auto; color: var(--green); font-size: 11px; opacity: 0; }
.toc-link.done .chk { opacity: 1; }

/* 主内容 */
.content { overflow-y: auto; position: relative; display: flex; flex-direction: column; }
.content .view { flex: 0 0 auto; }
.wrap { max-width: 900px; margin: 0 auto; padding: 40px 40px 120px; }
.wrap.narrow { max-width: var(--maxw); }

/* 玻璃卡 */
.glass {
  position: relative;
  background: var(--glass-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(12px);
  overflow: hidden;
  transition: background-color .35s ease, border-color .35s ease;
}
.glass::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: linear-gradient(to bottom, var(--glass-top), transparent 34%);
}
html[data-theme="light"] .glass { box-shadow: 0 8px 26px -18px var(--shadow); }

/* Hero */
.hero { text-align: center; padding-top: 24px; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 5px 14px; border-radius: 100px; font-size: 11.5px; color: var(--text-2);
  border: 1px solid color-mix(in srgb, var(--cyan) 30%, transparent);
  background: linear-gradient(90deg, color-mix(in srgb, var(--cyan) 10%, transparent), color-mix(in srgb, var(--grape) 6%, transparent));
}
.pulse { width: 6px; height: 6px; border-radius: 50%; background: var(--accent);
  box-shadow: 0 0 8px var(--accent); animation: blink 1.8s ease-in-out infinite; }
@keyframes blink { 0%,100% { opacity: .5; } 50% { opacity: 1; box-shadow: 0 0 12px 2px var(--accent); } }
body.reduce-motion .pulse { animation: none; }
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(44px, 8vw, 72px); line-height: 0.98; letter-spacing: -2.5px;
  margin: 22px 0 0; font-weight: 800; color: var(--fg-strong);
}
.hero .shiny {
  font-family: var(--font-display);
  font-size: clamp(44px, 8vw, 72px); line-height: 1; letter-spacing: -2.5px;
  font-weight: 800; margin: 0;
  background: linear-gradient(90deg, var(--cyan), var(--brand-blue), var(--grape), var(--cyan));
  background-size: 200% auto;
  -webkit-background-clip: text; background-clip: text; color: transparent;
  animation: shine 6s linear infinite;
}
@keyframes shine { to { background-position: 200% center; } }
body.reduce-motion .hero .shiny { animation: none; }
.hero p.lead {
  max-width: 520px; margin: 20px auto 0; color: var(--text-2);
  font-size: 14px; line-height: 1.8;
}
.cta { display: flex; gap: 12px; justify-content: center; margin-top: 28px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: 100px; font-size: 13.5px; font-weight: 700;
  cursor: pointer; border: 1px solid transparent; font-family: inherit;
  transition: transform .12s, box-shadow .18s, background .18s;
}
.btn-primary {
  color: #06213a;
  background: linear-gradient(120deg, var(--ice), var(--cyan) 55%, var(--brand-blue));
  box-shadow: 0 8px 26px -6px color-mix(in srgb, var(--cyan) 55%, transparent);
  position: relative; overflow: hidden;
}
.btn-primary::after {
  content: ""; position: absolute; top: 0; left: -60%; width: 40%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.5), transparent);
  transform: skewX(-20deg); animation: sweep 2.8s ease-in-out infinite;
}
@keyframes sweep { 0% { left: -60%; } 60%,100% { left: 130%; } }
body.reduce-motion .btn-primary::after { display: none; }
.btn-primary:hover { transform: translateY(-1px) scale(1.02); }
.btn-ghost { color: var(--fg-strong); border-color: var(--border-strong); background: var(--fill-soft); }
.btn-ghost:hover { background: var(--fill-hover); }

/* 统计 */
.stats { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 40px; }
.stat { min-width: 120px; padding: 16px 22px; border-radius: 16px; }
.stat b {
  display: block; font-size: 28px; font-weight: 800; letter-spacing: -0.8px;
  font-family: var(--font-display);
  background: linear-gradient(120deg, var(--fg-strong), var(--c, var(--accent)));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat span { font-size: 11px; color: var(--text-4); letter-spacing: .4px; }

/* 卡片网格 */
.section-h { font-size: 12px; letter-spacing: 2px; text-transform: uppercase; color: var(--text-4);
  text-align: center; margin: 60px 0 18px; }
.cap-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.cap { padding: 18px; border-radius: 18px; }
.cap .ico {
  width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center;
  font-size: 17px; color: var(--c); border: 1px solid color-mix(in srgb, var(--c) 40%, transparent);
  background: color-mix(in srgb, var(--c) 20%, transparent);
  box-shadow: 0 0 16px -4px color-mix(in srgb, var(--c) 60%, transparent);
}
.cap h3 { font-size: 15px; margin: 14px 0 6px; letter-spacing: -0.2px; color: var(--fg-strong); }
.cap p { font-size: 12px; color: var(--text-3); line-height: 1.65; margin: 0 0 12px; }
.tags { display: flex; flex-wrap: wrap; gap: 5px; }
.tag { font-size: 10.5px; padding: 4px 9px; border-radius: 100px; color: var(--text-2);
  border: 1px solid var(--border); background: var(--fill-soft); }

.chip-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.chip-card { padding: 14px; border-radius: 14px; cursor: pointer; transition: border-color .16s, background .16s, transform .16s; }
.chip-card:hover { transform: translateY(-2px); border-color: color-mix(in srgb, var(--c) 45%, transparent); }
.chip-card .row1 { display: flex; align-items: center; gap: 8px; font-size: 9.5px; color: var(--text-4); }
.chip-card .row1 .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--c); }
.chip-card h4 { margin: 12px 0 4px; font-size: 13px; font-weight: 600; color: var(--fg-strong); }
.chip-card small { font-size: 10.5px; color: var(--text-4); }

/* 阅读器 */
.reader-head .kicker { font-size: 11px; font-weight: 600; letter-spacing: .6px; color: var(--accent); }
.reader-head h1 { font-family: var(--font-display); font-size: 30px; letter-spacing: -0.8px;
  margin: 8px 0 6px; color: var(--fg-strong); }
.reader-head .sum { color: var(--text-3); font-size: 13.5px; line-height: 1.7; margin-bottom: 16px; }
.reader-toolbar {
  position: sticky; top: 0; z-index: 5; display: flex; align-items: center; gap: 10px;
  flex-wrap: wrap;
  padding: 8px 0; margin-bottom: 14px;
  background: linear-gradient(to bottom, var(--veil), transparent);
  backdrop-filter: blur(6px);
}
.seg { display: inline-flex; padding: 2px; border: 1px solid var(--border); border-radius: 9px; background: var(--fill-soft); }
.seg button { font-family: inherit; border: 0; background: transparent; color: var(--text-3);
  font-size: 11.5px; padding: 5px 11px; border-radius: 7px; cursor: pointer; }
.seg button.on { background: var(--fill-hover); color: var(--fg-strong); }
.tool { width: 32px; height: 32px; border-radius: 9px; border: 1px solid transparent;
  background: transparent; color: var(--text-2); cursor: pointer; font-size: 15px;
  display: grid; place-items: center; transition: background .14s; }
.tool:hover { background: var(--fill-hover); color: var(--fg-strong); }
.tool.on { color: var(--accent); background: color-mix(in srgb, var(--cyan) 12%, transparent); border-color: color-mix(in srgb, var(--cyan) 30%, transparent); }

.prose p { font-size: 15px; line-height: 1.9; color: var(--text-2); letter-spacing: .2px; margin: 0 0 15px; }
.prose h2 {
  font-family: var(--font-display); font-size: 20px; font-weight: 700; letter-spacing: .1px;
  color: var(--fg-strong); margin: 34px 0 12px; display: flex; align-items: center; gap: 10px;
}
.prose h2 .num { font-family: var(--font-code); font-size: 11px; font-weight: 700; letter-spacing: .6px;
  color: var(--accent); padding: 3px 7px; border-radius: 6px; background: color-mix(in srgb, var(--cyan) 12%, transparent); }
.prose h3 { font-size: 15px; color: var(--fg-strong); margin: 22px 0 8px; font-weight: 600; }
.prose ul, .prose ol { margin: 0 0 16px; padding-left: 4px; list-style: none; }
.prose li { position: relative; padding-left: 22px; margin-bottom: 9px; font-size: 14px; line-height: 1.75; color: var(--text-2); }
.prose ul li::before { content: ""; position: absolute; left: 4px; top: 9px; width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }
.prose ol { counter-reset: it; }
.prose ol li { counter-increment: it; }
.prose ol li::before { content: counter(it); position: absolute; left: 0; top: 1px; font-family: var(--font-code); font-size: 12px; font-weight: 700; color: var(--accent); }
.prose .note { border-left: 3px solid var(--amber); padding: 12px 16px; border-radius: 0 12px 12px 0;
  background: color-mix(in srgb, var(--amber) 10%, transparent); margin: 0 0 16px; color: var(--text-2); font-size: 13.5px; line-height: 1.7; }
.prose .note.key { border-color: var(--accent); background: color-mix(in srgb, var(--cyan) 8%, transparent); }
.prose table { width: 100%; border-collapse: collapse; margin: 0 0 20px; font-size: 13px; }
.prose th, .prose td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); }
.prose th { color: var(--fg-strong); font-weight: 700; background: var(--fill-soft); }
.prose td { color: var(--text-2); }
.prose code.inline { font-family: var(--font-code); font-size: 12.5px; padding: 2px 6px; border-radius: 6px;
  background: color-mix(in srgb, var(--cyan) 12%, transparent); color: var(--accent); }

/* 代码块（恒为深色，保证可读） */
.code { border-radius: 14px; margin: 0 0 20px; overflow: hidden; background: var(--code-bg); border: 1px solid var(--code-brd); }
.code::before { display: none; }   /* 关闭玻璃高光，避免亮色主题下代码块顶部发白 */
.code .code-bar { display: flex; align-items: center; gap: 10px; padding: 8px 12px; border-bottom: 1px solid var(--code-brd); }
.code-lang { font-family: var(--font-code); font-size: 9.5px; font-weight: 700; letter-spacing: 1px;
  padding: 2.5px 7px; border-radius: 5px; color: #54c5f8; background: rgba(84, 197, 248, 0.16); }
.code-lang.bash { color: #a78bfa; background: rgba(167,139,250,0.16); }
.code-lang.yaml, .code-lang.json { color: #34d399; background: rgba(52,211,153,0.16); }
.code-copy { margin-left: auto; font-size: 11px; color: #9aa4b2; background: transparent;
  border: 1px solid var(--code-brd); border-radius: 7px; padding: 4px 10px; cursor: pointer; font-family: inherit; }
.code-copy:hover { color: #fff; background: rgba(255,255,255,0.08); }
.code pre { margin: 0; padding: 14px 16px; overflow-x: auto; }
.code pre code { font-family: var(--font-code); font-size: 13px; line-height: 1.7; color: #9aa4b2; white-space: pre; }
.code .tk-com { color: #4e5766; font-style: italic; }
.code .tk-str { color: #a4f4fd; }
.code .tk-key { color: #54c5f8; }
.code .tk-num { color: #fbbf24; }
.code .tk-typ { color: #ffffff; }
.code .tk-fn  { color: #00d2ff; }
.code .tk-ann { color: #a78bfa; }

/* 自测 */
.quiz .q { padding: 16px; border-radius: 14px; margin-bottom: 14px; }
.quiz .q .prompt { font-size: 14.5px; font-weight: 600; color: var(--fg-strong); margin-bottom: 12px; }
.quiz .q .idx { font-family: var(--font-code); color: var(--accent); font-weight: 700; margin-right: 10px; }
.opt { display: flex; align-items: center; gap: 12px; padding: 11px 12px; border-radius: 11px;
  border: 1px solid var(--border); background: var(--fill-soft); margin-bottom: 8px; cursor: pointer;
  font-size: 13.5px; color: var(--text-1); transition: border-color .15s, background .15s; }
.opt:hover { border-color: var(--border-strong); }
.opt .mk { width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center;
  font-size: 11px; font-weight: 700; flex: 0 0 auto; border: 1px solid var(--border-strong); color: var(--text-3); }
.opt.sel { border-color: color-mix(in srgb, var(--cyan) 70%, transparent); background: color-mix(in srgb, var(--cyan) 10%, transparent); }
.opt.sel .mk { color: var(--accent); border-color: var(--accent); }
.opt.correct { border-color: rgba(52,211,153,0.7); background: rgba(52,211,153,0.12); }
.opt.correct .mk { color: var(--green); border-color: var(--green); }
.opt.wrong { border-color: rgba(248,113,113,0.7); background: rgba(248,113,113,0.12); }
.opt.wrong .mk { color: #f87171; border-color: #f87171; }
.q-explain { margin-top: 8px; padding: 10px 12px; border-radius: 10px; font-size: 12.5px;
  color: var(--text-2); background: var(--fill-soft); border: 1px solid var(--border); }
.quiz-foot { display: flex; align-items: center; gap: 12px; margin-top: 6px; }

/* 演练场 */
.lab { display: grid; grid-template-columns: 300px 1fr; gap: 18px; align-items: start; }
.lab .controls { padding: 18px; border-radius: 16px; display: flex; flex-direction: column; gap: 14px; }
.lab .ctrl label { font-size: 11.5px; color: var(--text-3); display: block; margin-bottom: 5px; }
.lab .ctrl output { float: right; color: var(--accent); font-family: var(--font-code); }
.lab input[type=range] { width: 100%; accent-color: var(--accent); }
.lab .stage { padding: 20px; border-radius: 16px; min-height: 280px; display: grid; place-items: center; }
.lab select, .lab input[type=text] { width: 100%; padding: 8px 10px; border-radius: 9px; font-family: inherit;
  background: var(--panel); color: var(--text-1); border: 1px solid var(--border); }
@media (max-width: 720px) { .lab { grid-template-columns: 1fr; } }

/* 进度页 */
.dash { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.dash .d-card { padding: 20px; border-radius: 18px; }
.dash .d-card h3 { margin: 0 0 14px; font-size: 14px; color: var(--fg-strong); }
.bar { height: 6px; border-radius: 100px; background: var(--track); overflow: hidden; margin-top: 8px; }
.bar i { display: block; height: 100%; border-radius: 100px;
  background: linear-gradient(90deg, var(--cyan), var(--grape)); transition: width .5s cubic-bezier(.22,1,.36,1); }
.d-row { display: flex; justify-content: space-between; font-size: 12px; color: var(--text-2); margin-top: 14px; }
.donut-wrap { display: flex; align-items: center; gap: 20px; }
.donut { font-size: 26px; font-weight: 800; color: var(--fg-strong); }

/* 命令面板 */
.overlay { position: fixed; inset: 0; z-index: 40; background: var(--overlay-bg);
  backdrop-filter: blur(6px); display: none; align-items: flex-start; justify-content: center; padding-top: 12vh; }
.overlay.open { display: flex; }
.palette { width: min(640px, 92vw); border-radius: 16px; overflow: hidden;
  background: var(--panel-solid); border: 1px solid var(--border-strong); box-shadow: 0 30px 80px var(--shadow); }
.palette input { width: 100%; padding: 18px 20px; background: transparent; border: 0; outline: none;
  color: var(--fg-strong); font-size: 16px; font-family: inherit; border-bottom: 1px solid var(--border); }
.results { max-height: 52vh; overflow-y: auto; padding: 8px; }
.res { display: flex; flex-direction: column; gap: 2px; padding: 11px 14px; border-radius: 10px; cursor: pointer; }
.res:hover, .res.active { background: color-mix(in srgb, var(--cyan) 12%, transparent); }
.res .t { font-size: 13.5px; color: var(--fg-strong); }
.res .s { font-size: 11.5px; color: var(--text-3); }
.res .grp { font-size: 9.5px; letter-spacing: .5px; text-transform: uppercase; color: var(--accent); }

/* toast */
.toast { position: fixed; bottom: 26px; left: 50%; transform: translateX(-50%) translateY(20px);
  background: var(--panel-solid); border: 1px solid var(--border-strong); color: var(--fg-strong);
  padding: 11px 18px; border-radius: 12px; font-size: 13px; z-index: 60; opacity: 0;
  pointer-events: none; transition: opacity .2s, transform .2s; backdrop-filter: blur(10px); }
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

.footer { margin-top: 60px; padding-top: 18px; border-top: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px; color: var(--text-4); font-size: 11.5px; }
.footer a { color: var(--text-3); text-decoration: none; }
.footer a:hover { color: var(--accent); }

/* 站点页脚（版权 / 备案）：所有页面底部居中；内容不足一屏时贴合视口底部 */
.site-footer {
  margin-top: auto;
  padding: 16px 20px calc(16px + env(safe-area-inset-bottom, 0px));
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-3);
  font-size: 11.5px;
  line-height: 1.6;
  letter-spacing: .2px;
}
.site-footer span { display: inline-block; }

.mobile-toggle { display: none; }

/* 移动端抽屉遮罩 */
.nav-backdrop {
  position: fixed; inset: 52px 0 0 0; z-index: 28;
  background: rgba(0, 0, 0, 0.45);
  opacity: 0; pointer-events: none; transition: opacity .25s;
}
body.nav-open .nav-backdrop { opacity: 1; pointer-events: auto; }
@media (min-width: 761px) { .nav-backdrop { display: none; } }

/* 响应式 */
@media (max-width: 900px) {
  .cap-grid { grid-template-columns: repeat(2, 1fr); }
  .chip-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 760px) {
  .app { grid-template-columns: 1fr; }
  .topbar { grid-column: 1; }
  .sidebar {
    position: fixed; z-index: 30; left: 0; top: 52px; bottom: 0; width: 84%;
    max-width: 300px; transform: translateX(-100%); background: var(--panel);
    transition: transform .28s cubic-bezier(.22,1,.36,1);
  }
  body.nav-open .sidebar { transform: translateX(0); box-shadow: 30px 0 60px var(--shadow); }
  .mobile-toggle { display: grid; }
  .wrap { padding: 28px 20px 100px; }
  /* 宽表格改为可横向滚动 */
  .prose table { display: block; overflow-x: auto; max-width: 100%; }
  .prose table th, .prose table td { white-space: nowrap; }
}
@media (max-width: 560px) {
  .cap-grid, .chip-grid, .dash { grid-template-columns: 1fr; }
  .topbar { gap: 8px; padding: 0 10px; }
  .brand { font-size: 13px; }
  .progress-chip { display: none; }
  #search-btn .s-txt { display: none; }
  #search-btn { padding: 7px 10px; }
  .wrap { padding: 22px 16px 90px; }
  .reader-head h1 { font-size: 24px; }
  .stats { gap: 8px; }
  .stat { min-width: 88px; padding: 12px 14px; }
  .stat b { font-size: 22px; }
  .cta .btn { flex: 1; justify-content: center; }
}
@media (max-width: 380px) {
  .brand .brand-txt { display: none; }
  .hero h1, .hero .shiny { letter-spacing: -1.5px; }
}
/* 横屏矮设备 */
@media (max-height: 520px) and (orientation: landscape) {
  .app { grid-template-rows: 48px 1fr; }
  .sidebar { top: 48px; }
  .nav-backdrop { inset: 48px 0 0 0; }
  .wrap { padding-top: 18px; }
  .hero { padding-top: 8px; }
  .section-h { margin: 32px 0 14px; }
}
/* 触摸设备 */
@media (hover: none) {
  .chip-card:hover { transform: none; }
  .btn-primary:hover { transform: none; }
  .nav-item, .toc-link, .opt, .tool { -webkit-tap-highlight-color: transparent; }
}
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: var(--scroll); border-radius: 8px; border: 2px solid transparent; background-clip: padding-box; }
::-webkit-scrollbar-thumb:hover { background: color-mix(in srgb, var(--scroll) 160%, transparent); background-clip: padding-box; }

/* 阅读器字号缩放（由 --rs 变量驱动，工具栏 A+/A− 调节） */
.prose { font-size: calc(15px * var(--rs, 1)); }
.prose p { font-size: 1em; }
.prose h2 { font-size: 1.32em; }
.prose h3 { font-size: 1.03em; }
.prose li { font-size: 0.93em; }
.prose table { font-size: 0.86em; }
.prose .note { font-size: 0.9em; }