/* ===================== 主题变量 ===================== */
:root {
  --bg: #f4f6fb;
  --bg-elev: #ffffff;
  --bg-soft: #eef1f8;
  --sidebar-bg: #0f172a;
  --sidebar-fg: #cbd5e1;
  --sidebar-fg-dim: #7c8aa5;
  --sidebar-active: #1e293b;
  --text: #1f2733;
  --text-dim: #5b6675;
  --text-faint: #8b95a5;
  --border: #e2e7f0;
  --border-soft: #edf0f7;
  --primary: #2563eb;
  --primary-soft: #dbeafe;
  --primary-fg: #1d4ed8;
  --accent: #0ea5a4;
  --accent-soft: #cffafe;
  --warn: #d97706;
  --warn-soft: #fef3c7;
  --ok: #16a34a;
  --ok-soft: #dcfce7;
  --bad: #dc2626;
  --bad-soft: #fee2e2;
  --purple: #7c3aed;
  --purple-soft: #ede9fe;
  --shadow: 0 1px 2px rgba(16,24,40,.05), 0 8px 24px rgba(16,24,40,.06);
  --shadow-lg: 0 12px 40px rgba(16,24,40,.14);
  --radius: 14px;
  --radius-sm: 9px;
  --sidebar-w: 286px;
  --maxw: 940px;
  --mono: "SFMono-Regular", ui-monospace, Menlo, Consolas, "Courier New", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
}
html[data-theme="dark"] {
  --bg: #0b1120;
  --bg-elev: #121a2b;
  --bg-soft: #1a2336;
  --sidebar-bg: #070c17;
  --sidebar-fg: #b8c4d8;
  --sidebar-fg-dim: #647189;
  --sidebar-active: #18233a;
  --text: #e4eaf2;
  --text-dim: #a3afc2;
  --text-faint: #6b768a;
  --border: #233048;
  --border-soft: #1b2740;
  --primary: #60a5fa;
  --primary-soft: #1e293b;
  --primary-fg: #93c5fd;
  --accent: #2dd4bf;
  --accent-soft: #134e4a;
  --warn: #fbbf24;
  --warn-soft: #422c08;
  --ok: #4ade80;
  --ok-soft: #14331f;
  --bad: #f87171;
  --bad-soft: #3a1414;
  --purple: #a78bfa;
  --purple-soft: #2a1f4d;
  --shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.5);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  font-size: 15.5px;
}
a { color: var(--primary-fg); text-decoration: none; }
::selection { background: var(--primary-soft); }

/* ===================== 侧边栏 ===================== */
.sidebar {
  position: fixed; top: 0; left: 0; bottom: 0;
  width: var(--sidebar-w);
  background: var(--sidebar-bg);
  color: var(--sidebar-fg);
  display: flex; flex-direction: column;
  padding: 18px 14px 0;
  z-index: 40;
  overflow-y: auto;
  scrollbar-width: thin;
}
.brand { display: flex; align-items: center; gap: 11px; padding: 6px 8px 16px; }
.brand-logo { width: 34px; height: 34px; flex: none; fill: none; stroke: #5eead4; stroke-width: 1.6; stroke-linecap: round; }
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-text strong { color: #fff; font-size: 18px; letter-spacing: .5px; }
.brand-text span { color: var(--sidebar-fg-dim); font-size: 11.5px; letter-spacing: .8px; }

.progress-card {
  display: flex; align-items: center; gap: 13px;
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.07);
  border-radius: var(--radius-sm);
  padding: 12px; margin: 4px 4px 16px;
}
.progress-ring-wrap { position: relative; width: 52px; height: 52px; flex: none; }
.progress-ring { width: 52px; height: 52px; transform: rotate(-90deg); }
.progress-ring .ring-bg { fill: none; stroke: rgba(255,255,255,.1); stroke-width: 5; }
.progress-ring .ring-fg { fill: none; stroke: #5eead4; stroke-width: 5; stroke-linecap: round; stroke-dasharray: 163.4; stroke-dashoffset: 163.4; transition: stroke-dashoffset .6s ease; }
.progress-ring-wrap span { position: absolute; inset: 0; display: grid; place-items: center; font-size: 12.5px; font-weight: 700; color: #fff; }
.progress-meta { display: flex; flex-direction: column; }
.progress-label { color: #fff; font-size: 13.5px; font-weight: 600; }
.progress-sub { color: var(--sidebar-fg-dim); font-size: 12px; }

.nav { display: flex; flex-direction: column; gap: 2px; padding-bottom: 10px; }
.nav-group-title {
  font-size: 11px; letter-spacing: 1.3px; text-transform: uppercase;
  color: var(--sidebar-fg-dim); padding: 16px 12px 7px; font-weight: 700;
}
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: 9px;
  color: var(--sidebar-fg); cursor: pointer;
  font-size: 14px; border: none; background: none; width: 100%; text-align: left;
  transition: background .15s, color .15s;
}
.nav-item:hover { background: rgba(255,255,255,.05); color: #fff; }
.nav-item.active { background: var(--sidebar-active); color: #fff; }
.nav-item.active .nav-num { background: #5eead4; color: #06302c; }
.nav-num {
  flex: none; width: 22px; height: 22px; border-radius: 6px;
  background: rgba(255,255,255,.09); color: var(--sidebar-fg);
  display: grid; place-items: center; font-size: 12px; font-weight: 700;
}
.nav-ic { width: 18px; height: 18px; flex: none; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.nav-label { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-check { flex: none; color: #5eead4; opacity: 0; transition: opacity .15s; }
.nav-item.done .nav-check { opacity: 1; }
.nav-badge { flex: none; font-size: 11px; background: rgba(255,255,255,.1); color: var(--sidebar-fg-dim); padding: 1px 7px; border-radius: 999px; }

.sidebar-foot { margin-top: auto; padding: 12px 6px 16px; }
.ghost-btn {
  width: 100%; padding: 8px; border-radius: 8px; cursor: pointer;
  background: transparent; border: 1px solid rgba(255,255,255,.12);
  color: var(--sidebar-fg-dim); font-size: 12.5px; transition: all .15s;
}
.ghost-btn:hover { color: #fff; border-color: rgba(255,255,255,.3); }

/* ===================== 主区域 ===================== */
.main { margin-left: var(--sidebar-w); min-height: 100vh; display: flex; flex-direction: column; }
.topbar {
  position: sticky; top: 0; z-index: 30;
  display: flex; align-items: center; gap: 12px;
  padding: 12px 26px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
}
.icon-btn {
  flex: none; width: 38px; height: 38px; border-radius: 10px;
  display: grid; place-items: center; cursor: pointer;
  background: var(--bg-elev); border: 1px solid var(--border); color: var(--text-dim);
  transition: all .15s;
}
.icon-btn:hover { color: var(--text); border-color: var(--primary); }
.icon-btn svg { width: 19px; height: 19px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
#menuBtn { display: none; }

.search-wrap { position: relative; flex: 1; max-width: 560px; }
.search-icon { position: absolute; left: 13px; top: 50%; transform: translateY(-50%); width: 17px; height: 17px; fill: none; stroke: var(--text-faint); stroke-width: 1.9; stroke-linecap: round; }
#searchInput {
  width: 100%; padding: 10px 14px 10px 38px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--bg-elev); color: var(--text);
  font-size: 14px; font-family: inherit; outline: none; transition: border .15s, box-shadow .15s;
}
#searchInput:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }
.search-clear { position: absolute; right: 10px; top: 50%; transform: translateY(-50%); font-size: 10.5px; color: var(--text-faint); border: 1px solid var(--border); border-radius: 5px; padding: 1px 5px; background: var(--bg-soft); }

.content { flex: 1; padding: 30px 26px 60px; max-width: calc(var(--maxw) + 52px); margin: 0 auto; width: 100%; }
.page-foot { padding: 18px 26px 30px; text-align: center; color: var(--text-faint); font-size: 12.5px; }

/* ===================== 通用排版 ===================== */
.eyebrow { display: inline-flex; align-items: center; gap: 7px; font-size: 12.5px; font-weight: 700; letter-spacing: .5px; color: var(--primary-fg); background: var(--primary-soft); padding: 4px 11px; border-radius: 999px; }
.page-title { font-size: 28px; font-weight: 800; margin: 14px 0 6px; letter-spacing: .3px; line-height: 1.3; }
.page-lead { color: var(--text-dim); font-size: 15.5px; margin: 0 0 8px; max-width: 70ch; }
.section-h { font-size: 20px; font-weight: 700; margin: 36px 0 4px; padding-bottom: 0; display: flex; align-items: center; gap: 10px; }
.section-h .sh-bar { width: 4px; height: 20px; border-radius: 3px; background: var(--primary); flex: none; }
.section-intro { color: var(--text-dim); margin: 8px 0 18px; font-size: 14.5px; }

/* 知识点卡片 */
.point {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 19px; margin: 12px 0; box-shadow: var(--shadow);
  transition: border-color .15s, transform .15s;
}
.point:hover { border-color: color-mix(in srgb, var(--primary) 40%, var(--border)); }
.point-title { font-size: 16px; font-weight: 700; margin: 0 0 7px; color: var(--text); display: flex; gap: 8px; align-items: baseline; }
.point-title::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--accent); flex: none; transform: translateY(-2px); }
.rich p { margin: 7px 0; color: var(--text-dim); }
.rich strong { color: var(--text); font-weight: 700; }
.rich ul, .rich ol { margin: 8px 0; padding-left: 22px; color: var(--text-dim); }
.rich li { margin: 4px 0; }
.rich ul li::marker { color: var(--accent); }

/* 表格 */
.tbl-wrap { margin: 16px 0; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.tbl-title { padding: 10px 16px; font-weight: 700; font-size: 14px; background: var(--bg-soft); border-bottom: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; font-size: 13.8px; }
thead th { background: var(--bg-soft); color: var(--text); text-align: left; padding: 10px 14px; font-weight: 700; border-bottom: 2px solid var(--border); }
tbody td { padding: 9px 14px; border-bottom: 1px solid var(--border-soft); color: var(--text-dim); vertical-align: top; }
tbody tr:last-child td { border-bottom: none; }
tbody tr:nth-child(even) { background: color-mix(in srgb, var(--bg-soft) 50%, transparent); }

/* 考点提示 */
.callout { display: flex; gap: 13px; background: var(--warn-soft); border: 1px solid color-mix(in srgb, var(--warn) 30%, transparent); border-radius: var(--radius); padding: 15px 18px; margin: 18px 0; }
.callout .callout-ic { flex: none; width: 22px; height: 22px; color: var(--warn); }
.callout .callout-ic svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.callout-body h4 { margin: 0 0 6px; font-size: 14.5px; color: var(--text); }
.callout-body ul { margin: 0; padding-left: 18px; }
.callout-body li { color: var(--text-dim); margin: 3px 0; font-size: 14px; }

/* 名词表 */
.terms-grid { display: grid; grid-template-columns: 1fr; gap: 0; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.term-row { display: grid; grid-template-columns: 170px 1fr; gap: 14px; padding: 13px 18px; border-bottom: 1px solid var(--border-soft); }
.term-row:last-child { border-bottom: none; }
.term-row:nth-child(even) { background: color-mix(in srgb, var(--bg-soft) 50%, transparent); }
.term-name { font-weight: 700; color: var(--primary-fg); }
.term-def { color: var(--text-dim); font-size: 14.2px; }

/* ===================== 首页 ===================== */
.hero { background: linear-gradient(135deg, var(--sidebar-bg), #1e3a5f); border-radius: 20px; padding: 38px 34px; color: #e2e8f0; position: relative; overflow: hidden; box-shadow: var(--shadow-lg); }
.hero::after { content: ""; position: absolute; right: -60px; top: -60px; width: 260px; height: 260px; background: radial-gradient(circle, rgba(94,234,212,.18), transparent 70%); }
.hero h1 { margin: 0 0 10px; font-size: 32px; color: #fff; font-weight: 800; }
.hero p { margin: 0; max-width: 60ch; color: #c2d0e4; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 18px; }
.hero-tag { font-size: 12.5px; background: rgba(255,255,255,.1); border: 1px solid rgba(255,255,255,.15); padding: 5px 12px; border-radius: 999px; color: #dbeafe; }

.cards-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(252px, 1fr)); gap: 16px; margin: 22px 0; }
.ch-card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 19px; cursor: pointer; box-shadow: var(--shadow); transition: transform .15s, border-color .15s, box-shadow .15s; position: relative; overflow: hidden; }
.ch-card:hover { transform: translateY(-3px); border-color: var(--primary); box-shadow: var(--shadow-lg); }
.ch-card .ch-cat { font-size: 11.5px; color: var(--accent); font-weight: 700; letter-spacing: .5px; }
.ch-card .ch-num { position: absolute; right: 14px; top: 10px; font-size: 46px; font-weight: 800; color: var(--bg-soft); line-height: 1; }
.ch-card h3 { margin: 6px 0 8px; font-size: 17px; position: relative; }
.ch-card .ch-desc { color: var(--text-dim); font-size: 13.5px; margin: 0; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.ch-card .ch-foot { margin-top: 13px; display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--text-faint); }
.ch-card .ch-done { color: var(--ok); font-weight: 700; }

.quick-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 13px; }
.quick-card { display: flex; align-items: center; gap: 12px; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 14px 16px; cursor: pointer; transition: all .15s; box-shadow: var(--shadow); }
.quick-card:hover { border-color: var(--primary); transform: translateY(-2px); }
.quick-ic { flex: none; width: 38px; height: 38px; border-radius: 10px; display: grid; place-items: center; }
.quick-ic svg { width: 20px; height: 20px; fill: none; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.quick-card b { font-size: 14.5px; display: block; }
.quick-card span { font-size: 12px; color: var(--text-faint); }

/* ===================== 题库 ===================== */
.tabs { display: flex; gap: 6px; flex-wrap: wrap; border-bottom: 1px solid var(--border); margin: 20px 0 22px; }
.tab { padding: 9px 16px; cursor: pointer; border: none; background: none; color: var(--text-dim); font-size: 14.5px; font-weight: 600; border-bottom: 2.5px solid transparent; margin-bottom: -1px; font-family: inherit; transition: color .15s, border-color .15s; }
.tab:hover { color: var(--text); }
.tab.active { color: var(--primary-fg); border-color: var(--primary); }
.tab .tab-count { font-size: 11.5px; color: var(--text-faint); margin-left: 5px; }

.q-toolbar { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; }
.btn { display: inline-flex; align-items: center; gap: 7px; padding: 8px 15px; border-radius: 9px; border: 1px solid var(--border); background: var(--bg-elev); color: var(--text); cursor: pointer; font-size: 13.5px; font-weight: 600; font-family: inherit; transition: all .15s; }
.btn:hover { border-color: var(--primary); }
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.q-hint { color: var(--text-faint); font-size: 13px; margin-left: auto; }

/* 题目卡 */
.q-card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 17px 20px; margin: 13px 0; box-shadow: var(--shadow); }
.q-head { display: flex; gap: 11px; align-items: flex-start; }
.q-idx { flex: none; min-width: 26px; height: 26px; padding: 0 6px; border-radius: 7px; background: var(--bg-soft); color: var(--text-dim); font-weight: 700; font-size: 13px; display: grid; place-items: center; }
.q-stem { font-weight: 600; font-size: 15.3px; flex: 1; }
.q-tag { font-size: 11px; padding: 2px 8px; border-radius: 999px; font-weight: 700; flex: none; }
.q-tag.single { background: var(--primary-soft); color: var(--primary-fg); }
.q-tag.multi { background: var(--purple-soft); color: var(--purple); }

.opts { list-style: none; margin: 13px 0 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.opt { display: flex; gap: 11px; align-items: flex-start; padding: 10px 13px; border: 1px solid var(--border); border-radius: 10px; cursor: pointer; transition: all .13s; }
.opt:hover { border-color: var(--primary); background: var(--bg-soft); }
.opt.sel { border-color: var(--primary); background: var(--primary-soft); }
.opt.correct { border-color: var(--ok); background: var(--ok-soft); }
.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt-label { flex: none; width: 24px; height: 24px; border-radius: 7px; border: 1.5px solid var(--border); display: grid; place-items: center; font-weight: 700; font-size: 13px; color: var(--text-dim); }
.opt.sel .opt-label { background: var(--primary); border-color: var(--primary); color: #fff; }
.opt.correct .opt-label { background: var(--ok); border-color: var(--ok); color: #fff; }
.opt.wrong .opt-label { background: var(--bad); border-color: var(--bad); color: #fff; }
.opt-text { flex: 1; font-size: 14.2px; padding-top: 2px; }

.reveal { margin-top: 14px; border-top: 1px dashed var(--border); padding-top: 13px; }
.reveal.hidden { display: none; }
.ans-line { display: flex; gap: 8px; align-items: baseline; font-size: 14.5px; }
.ans-badge { font-weight: 700; color: var(--ok); }
.ans-val { font-weight: 700; color: var(--text); }
.ans-expl { color: var(--text-dim); font-size: 13.8px; margin-top: 6px; }

.fill-q { font-size: 15.3px; font-weight: 600; }
.fill-q .blank { color: var(--primary-fg); border-bottom: 2px solid var(--primary); padding: 0 16px; font-weight: 700; }
.tf-btns { display: flex; gap: 10px; margin-top: 12px; }
.tf-btn { padding: 8px 22px; border-radius: 9px; border: 1px solid var(--border); background: var(--bg-elev); cursor: pointer; font-weight: 700; font-size: 14px; font-family: inherit; color: var(--text-dim); transition: all .13s; }
.tf-btn:hover { border-color: var(--primary); }
.tf-btn.sel-t { background: var(--ok-soft); border-color: var(--ok); color: var(--ok); }
.tf-btn.sel-f { background: var(--bad-soft); border-color: var(--bad); color: var(--bad); }

/* 简答 / 名词解释 折叠 */
.sa-toggle { display: inline-flex; align-items: center; gap: 6px; margin-top: 11px; color: var(--primary-fg); font-size: 13.5px; font-weight: 600; cursor: pointer; background: none; border: none; font-family: inherit; padding: 0; }
.sa-toggle svg { width: 15px; height: 15px; transition: transform .2s; fill: none; stroke: currentColor; stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }
.sa-toggle.open svg { transform: rotate(180deg); }
.sa-answer { margin-top: 11px; background: var(--bg-soft); border-left: 3px solid var(--accent); border-radius: 0 10px 10px 0; padding: 13px 16px; color: var(--text-dim); font-size: 14.3px; }
.sa-answer.hidden { display: none; }

/* 闪卡 */
.flashcard { perspective: 1400px; max-width: 540px; margin: 24px auto; }
.fc-inner { position: relative; width: 100%; min-height: 230px; transition: transform .55s; transform-style: preserve-3d; cursor: pointer; }
.fc-inner.flipped { transform: rotateY(180deg); }
.fc-face { position: absolute; inset: 0; backface-visibility: hidden; border-radius: 18px; padding: 30px; display: flex; flex-direction: column; justify-content: center; align-items: center; text-align: center; box-shadow: var(--shadow-lg); border: 1px solid var(--border); }
.fc-front { background: var(--bg-elev); }
.fc-front .fc-term { font-size: 26px; font-weight: 800; color: var(--text); }
.fc-front .fc-hint { margin-top: 14px; color: var(--text-faint); font-size: 13px; }
.fc-back { background: linear-gradient(135deg, #1e3a5f, var(--sidebar-bg)); color: #e2e8f0; transform: rotateY(180deg); }
.fc-back .fc-def { font-size: 15px; line-height: 1.75; }
.fc-nav { display: flex; align-items: center; justify-content: center; gap: 16px; margin-top: 20px; }
.fc-counter { font-size: 14px; color: var(--text-dim); min-width: 70px; text-align: center; font-weight: 600; }

/* 测验结果 */
.quiz-result { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px; text-align: center; box-shadow: var(--shadow); margin-bottom: 20px; }
.quiz-score { font-size: 44px; font-weight: 800; color: var(--primary-fg); }
.quiz-result p { color: var(--text-dim); margin: 6px 0 0; }

/* 搜索结果 */
.search-result { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 14px 17px; margin: 10px 0; cursor: pointer; box-shadow: var(--shadow); transition: border-color .15s; }
.search-result:hover { border-color: var(--primary); }
.sr-kind { font-size: 11px; font-weight: 700; padding: 2px 8px; border-radius: 999px; background: var(--accent-soft); color: var(--accent); }
.sr-title { font-weight: 700; margin: 7px 0 3px; font-size: 15px; }
.sr-snippet { color: var(--text-dim); font-size: 13.5px; }
.sr-crumb { color: var(--text-faint); font-size: 12px; margin-top: 5px; }
mark { background: #fde68a; color: inherit; border-radius: 3px; padding: 0 1px; }
html[data-theme="dark"] mark { background: #92710d; color: #fff; }

.empty { text-align: center; padding: 60px 20px; color: var(--text-faint); }
.empty svg { width: 50px; height: 50px; opacity: .4; margin-bottom: 12px; fill: none; stroke: currentColor; stroke-width: 1.5; }

/* PPT 原文折叠 */
.ppt-block { margin-top: 30px; }
details.ppt { border: 1px dashed var(--border); border-radius: var(--radius); padding: 0; background: var(--bg-soft); overflow: hidden; }
details.ppt > summary { cursor: pointer; padding: 13px 18px; font-weight: 600; font-size: 14px; color: var(--text-dim); list-style: none; display: flex; align-items: center; gap: 8px; }
details.ppt > summary::-webkit-details-marker { display: none; }
details.ppt > summary::before { content: "▸"; color: var(--text-faint); transition: transform .2s; }
details.ppt[open] > summary::before { transform: rotate(90deg); }

.chip-row { display: flex; gap: 8px; flex-wrap: wrap; margin: 14px 0 4px; }
.chip { font-size: 12.5px; padding: 4px 11px; border-radius: 999px; background: var(--bg-soft); border: 1px solid var(--border); color: var(--text-dim); cursor: pointer; transition: all .13s; }
.chip:hover { border-color: var(--primary); color: var(--primary-fg); }
.chip.active { background: var(--primary); border-color: var(--primary); color: #fff; }

.mark-done-bar { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin: 30px 0 0; padding: 18px 20px; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); flex-wrap: wrap; }
.mark-done-bar .mdb-text { color: var(--text-dim); font-size: 14px; }
.pager { display: flex; gap: 10px; }

/* ===================== 响应式 ===================== */
@media (max-width: 980px) {
  :root { --sidebar-w: 270px; }
  .sidebar { transform: translateX(-100%); transition: transform .25s ease; box-shadow: var(--shadow-lg); }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; }
  #menuBtn { display: grid; }
  .backdrop { position: fixed; inset: 0; background: rgba(0,0,0,.5); z-index: 35; }
  .term-row { grid-template-columns: 1fr; gap: 4px; }
  .content { padding: 22px 16px 50px; }
  .topbar { padding: 11px 16px; }
}
@media (max-width: 560px) {
  .page-title { font-size: 23px; }
  .hero { padding: 26px 22px; }
  .hero h1 { font-size: 25px; }
  .q-card, .point { padding: 14px 15px; }
}

/* ===================== Awwwards-style experimental layer ===================== */
:root {
  --cream: #f8f6e8;
  --blush: #eddcd5;
  --mauve: #dac2c6;
  --mint: #ddead0;
  --olive: #85ac7e;
  --ink: #263024;
  --ink-soft: #5f6759;
  --glass: rgba(248, 246, 232, .58);
  --glass-strong: rgba(248, 246, 232, .78);
  --glass-line: rgba(133, 172, 126, .26);
  --bg: #f8f6e8;
  --bg-elev: rgba(248, 246, 232, .72);
  --bg-soft: rgba(221, 234, 208, .46);
  --sidebar-bg: rgba(38, 48, 36, .78);
  --sidebar-fg: rgba(248, 246, 232, .88);
  --sidebar-fg-dim: rgba(248, 246, 232, .56);
  --sidebar-active: rgba(248, 246, 232, .14);
  --text: #263024;
  --text-dim: #5f6759;
  --text-faint: rgba(95, 103, 89, .68);
  --border: rgba(133, 172, 126, .24);
  --border-soft: rgba(218, 194, 198, .34);
  --primary: #85ac7e;
  --primary-soft: rgba(221, 234, 208, .72);
  --primary-fg: #597954;
  --accent: #b7898f;
  --accent-soft: rgba(218, 194, 198, .58);
  --warn: #a98754;
  --warn-soft: rgba(237, 220, 213, .7);
  --ok: #6f9667;
  --ok-soft: rgba(221, 234, 208, .76);
  --bad: #b36c75;
  --bad-soft: rgba(237, 220, 213, .78);
  --purple: #9a7a88;
  --purple-soft: rgba(218, 194, 198, .62);
  --shadow: 0 18px 55px rgba(78, 88, 69, .10), inset 0 1px 0 rgba(255,255,255,.58);
  --shadow-lg: 0 32px 90px rgba(65, 74, 55, .18), inset 0 1px 0 rgba(255,255,255,.62);
  --radius: 8px;
  --radius-sm: 8px;
  --sidebar-w: 318px;
  --maxw: 1180px;
  --sans: "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "Noto Serif SC", "Noto Sans SC", serif;
}

html[data-theme="dark"] {
  --bg: #263024;
  --bg-elev: rgba(55, 66, 51, .72);
  --bg-soft: rgba(133, 172, 126, .14);
  --sidebar-bg: rgba(19, 26, 18, .78);
  --sidebar-fg: rgba(248, 246, 232, .9);
  --sidebar-fg-dim: rgba(248, 246, 232, .58);
  --sidebar-active: rgba(221, 234, 208, .14);
  --text: #f8f6e8;
  --text-dim: rgba(248, 246, 232, .72);
  --text-faint: rgba(248, 246, 232, .48);
  --border: rgba(221, 234, 208, .22);
  --border-soft: rgba(237, 220, 213, .16);
  --primary: #ddead0;
  --primary-soft: rgba(221, 234, 208, .14);
  --primary-fg: #ddead0;
  --accent: #eddcd5;
  --accent-soft: rgba(237, 220, 213, .13);
  --glass: rgba(55, 66, 51, .5);
  --glass-strong: rgba(55, 66, 51, .72);
  --glass-line: rgba(221, 234, 208, .2);
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  min-height: 100vh;
  background:
    linear-gradient(118deg, rgba(248,246,232,.96) 0%, rgba(221,234,208,.76) 37%, rgba(237,220,213,.82) 68%, rgba(218,194,198,.78) 100%);
  color: var(--text);
  font-feature-settings: "kern" 1;
  letter-spacing: 0;
  overflow-x: hidden;
}

html[data-theme="dark"] body {
  background:
    linear-gradient(118deg, #263024 0%, #33402f 42%, #4a4546 72%, #1d241b 100%);
}

body::before,
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: -2;
}

body::before {
  background:
    linear-gradient(90deg, rgba(133,172,126,.10) 1px, transparent 1px),
    linear-gradient(0deg, rgba(133,172,126,.08) 1px, transparent 1px);
  background-size: 92px 92px;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,.8), rgba(0,0,0,.2) 70%, transparent);
}

body::after {
  background:
    conic-gradient(from 130deg at 20% 18%, rgba(237,220,213,.72), rgba(221,234,208,.22), rgba(218,194,198,.58), rgba(248,246,232,.12), rgba(237,220,213,.72)),
    linear-gradient(135deg, rgba(255,255,255,.32), transparent 45%);
  filter: blur(42px);
  opacity: .72;
  transform: scale(1.08);
  animation: fluidField 18s ease-in-out infinite alternate;
}

@keyframes fluidField {
  from { transform: translate3d(-1.5%, -1%, 0) scale(1.08) rotate(-1deg); }
  to { transform: translate3d(1.5%, 1%, 0) scale(1.12) rotate(1deg); }
}

.sidebar {
  border-right: 1px solid rgba(248,246,232,.16);
  background:
    linear-gradient(180deg, rgba(38,48,36,.9), rgba(38,48,36,.66)),
    linear-gradient(120deg, rgba(237,220,213,.18), transparent 54%);
  backdrop-filter: blur(26px) saturate(1.3);
  box-shadow: 22px 0 70px rgba(38, 48, 36, .18);
}

.brand {
  padding: 10px 10px 22px;
}

.brand-logo {
  width: 42px;
  height: 42px;
  stroke: var(--mint);
  filter: drop-shadow(0 10px 24px rgba(221,234,208,.28));
}

.brand-text strong,
.page-title,
.hero h1,
.section-h,
.ch-card h3,
.quiz-score,
.fc-front .fc-term {
  font-family: var(--display);
  font-weight: 900;
  font-variation-settings: "wght" 900;
}

.brand-text strong {
  color: var(--cream);
  font-size: 19px;
}

.progress-card,
.topbar,
.point,
.tbl-wrap,
.terms-grid,
.callout,
.ch-card,
.quick-card,
.q-card,
.quiz-result,
.search-result,
.mark-done-bar,
.fc-face,
details.ppt {
  background: linear-gradient(145deg, var(--glass-strong), rgba(255,255,255,.28));
  border: 1px solid var(--glass-line);
  backdrop-filter: blur(22px) saturate(1.35);
  -webkit-backdrop-filter: blur(22px) saturate(1.35);
  box-shadow: var(--shadow);
}

.progress-card {
  border-color: rgba(248,246,232,.18);
  background: rgba(248,246,232,.10);
}

.progress-ring .ring-fg {
  stroke: var(--mint);
  filter: drop-shadow(0 0 10px rgba(221,234,208,.55));
}

.nav {
  gap: 6px;
}

.nav-group-title {
  color: rgba(248,246,232,.42);
  letter-spacing: 1.8px;
}

.nav-item {
  min-height: 42px;
  border: 1px solid transparent;
  transition: transform .28s cubic-bezier(.2,.8,.2,1), background .28s, border-color .28s, color .28s;
}

.nav-item:hover,
.nav-item.active {
  background: rgba(248,246,232,.13);
  border-color: rgba(248,246,232,.16);
  color: var(--cream);
  transform: translateX(4px);
}

.nav-item.active .nav-num,
.chip.active,
.btn.primary {
  background: var(--olive);
  border-color: var(--olive);
  color: var(--cream);
}

.nav-num,
.nav-badge {
  border-radius: 8px;
  background: rgba(248,246,232,.12);
}

.main {
  position: relative;
}

.main::before {
  content: "";
  position: fixed;
  left: var(--sidebar-w);
  right: 0;
  top: 0;
  height: 160px;
  pointer-events: none;
  z-index: 1;
  background: linear-gradient(to bottom, rgba(248,246,232,.72), transparent);
}

html[data-theme="dark"] .main::before {
  background: linear-gradient(to bottom, rgba(38,48,36,.66), transparent);
}

.topbar {
  top: 16px;
  width: min(calc(100% - 52px), var(--maxw));
  margin: 0 auto;
  border-radius: 8px;
  padding: 12px 14px;
  z-index: 31;
}

.icon-btn,
#searchInput,
.btn,
.tab,
.tf-btn,
.ghost-btn,
.chip {
  border-radius: 8px;
}

.icon-btn,
#searchInput,
.btn,
.tf-btn,
.ghost-btn {
  background: rgba(248,246,232,.64);
  border-color: var(--border);
  backdrop-filter: blur(18px);
}

#searchInput {
  height: 44px;
  color: var(--text);
}

#searchInput:focus {
  border-color: var(--olive);
  box-shadow: 0 0 0 4px rgba(133,172,126,.18), 0 12px 38px rgba(133,172,126,.16);
}

.content {
  padding-top: 54px;
  max-width: calc(var(--maxw) + 52px);
}

.hero {
  min-height: clamp(390px, 48vh, 560px);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  border-radius: 8px;
  padding: clamp(34px, 6vw, 74px);
  color: var(--cream);
  background:
    linear-gradient(125deg, rgba(38,48,36,.92), rgba(133,172,126,.58) 48%, rgba(218,194,198,.68)),
    linear-gradient(20deg, rgba(248,246,232,.22), transparent 42%);
  box-shadow: var(--shadow-lg);
  isolation: isolate;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 18px;
  border: 1px solid rgba(248,246,232,.22);
  border-radius: 8px;
  pointer-events: none;
}

.hero::after {
  right: auto;
  left: 58%;
  top: -34%;
  width: 48%;
  height: 160%;
  background:
    linear-gradient(90deg, transparent, rgba(248,246,232,.26), transparent),
    repeating-linear-gradient(90deg, rgba(248,246,232,.18) 0 1px, transparent 1px 18px);
  transform: skewX(-16deg);
  animation: scanGlass 8s ease-in-out infinite alternate;
}

@keyframes scanGlass {
  from { transform: translateX(-12%) skewX(-16deg); opacity: .34; }
  to { transform: translateX(10%) skewX(-16deg); opacity: .58; }
}

.hero h1 {
  position: relative;
  z-index: 1;
  max-width: 820px;
  margin: 0 0 18px;
  color: var(--cream);
  font-size: clamp(40px, 7vw, 92px);
  line-height: .98;
}

.hero p {
  position: relative;
  z-index: 1;
  max-width: 720px;
  color: rgba(248,246,232,.78);
  font-size: clamp(15px, 1.35vw, 19px);
}

.hero-tags {
  position: relative;
  z-index: 1;
  margin-top: 30px;
}

.hero-tag,
.eyebrow,
.q-tag,
.sr-kind {
  border-radius: 999px;
  background: rgba(248,246,232,.18);
  border: 1px solid rgba(248,246,232,.24);
  color: inherit;
  backdrop-filter: blur(16px);
}

.eyebrow {
  color: var(--primary-fg);
  background: rgba(221,234,208,.58);
  border-color: rgba(133,172,126,.24);
}

.page-title {
  font-size: clamp(33px, 5vw, 72px);
  line-height: 1.04;
  margin: 18px 0 14px;
  color: var(--text);
}

.page-lead {
  max-width: 78ch;
  font-size: clamp(15px, 1.6vw, 19px);
}

.section-h {
  margin: 58px 0 16px;
  font-size: clamp(24px, 3vw, 42px);
  line-height: 1.08;
}

.section-h .sh-bar {
  width: 44px;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--olive), var(--mauve));
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  grid-auto-rows: minmax(150px, auto);
  gap: 16px;
  margin: 26px 0 42px;
}

.ch-card {
  grid-column: span 4;
  min-height: 212px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  transform-style: preserve-3d;
  transition: transform .42s cubic-bezier(.2,.8,.2,1), border-color .28s, box-shadow .28s;
}

.ch-card:nth-child(1),
.ch-card:nth-child(6n + 1) {
  grid-column: span 7;
  grid-row: span 2;
  min-height: 332px;
}

.ch-card:nth-child(2),
.ch-card:nth-child(6n + 5) {
  grid-column: span 5;
}

.ch-card:nth-child(3n) {
  background: linear-gradient(145deg, rgba(221,234,208,.78), rgba(248,246,232,.4));
}

.ch-card:nth-child(4n) {
  background: linear-gradient(145deg, rgba(237,220,213,.74), rgba(248,246,232,.38));
}

.ch-card:hover,
.quick-card:hover,
.q-card:hover,
.point:hover,
.search-result:hover {
  border-color: rgba(133,172,126,.48);
  box-shadow: var(--shadow-lg);
}

.ch-card .ch-num {
  right: 18px;
  top: 10px;
  color: rgba(133,172,126,.18);
  font-size: clamp(56px, 7vw, 104px);
  line-height: .9;
  font-family: var(--display);
}

.ch-card .ch-cat {
  color: var(--primary-fg);
}

.ch-card h3 {
  max-width: 86%;
  font-size: clamp(20px, 2vw, 31px);
  line-height: 1.15;
}

.quick-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 14px;
}

.quick-card {
  min-height: 118px;
  align-items: flex-end;
  padding: 18px;
  transition: transform .35s cubic-bezier(.2,.8,.2,1), border-color .25s, box-shadow .25s;
}

.quick-ic {
  width: 44px;
  height: 44px;
  background: rgba(221,234,208,.66) !important;
}

.point,
.q-card,
.search-result {
  padding: clamp(17px, 2vw, 26px);
}

.point-title {
  font-size: clamp(17px, 1.5vw, 22px);
}

.point-title::before {
  width: 24px;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--olive), var(--mauve));
}

.rich p,
.rich li,
tbody td,
.term-def,
.ans-expl,
.sa-answer {
  color: var(--text-dim);
}

.tbl-wrap {
  overflow-x: auto;
}

thead th {
  background: rgba(221,234,208,.48);
}

tbody tr:nth-child(even) {
  background: rgba(248,246,232,.32);
}

.callout {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(237,220,213,.84), rgba(221,234,208,.52));
}

.callout::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, transparent, rgba(248,246,232,.32), transparent);
  transform: translateX(-80%);
  animation: glassSweep 7s ease-in-out infinite;
}

@keyframes glassSweep {
  0%, 45% { transform: translateX(-95%); }
  70%, 100% { transform: translateX(95%); }
}

.tabs {
  gap: 8px;
  border-bottom: 0;
}

.tab {
  border: 1px solid var(--border);
  background: rgba(248,246,232,.52);
  backdrop-filter: blur(16px);
}

.tab.active {
  color: var(--cream);
  border-color: var(--olive);
  background: var(--olive);
}

.opt {
  border-radius: 8px;
  background: rgba(248,246,232,.36);
}

.opt:hover,
.opt.sel {
  background: rgba(221,234,208,.6);
}

.fc-inner {
  min-height: 300px;
}

.fc-front,
.fc-back {
  background: linear-gradient(145deg, rgba(248,246,232,.8), rgba(221,234,208,.45));
}

.fc-back {
  color: var(--text);
}

.cursor-dot,
.cursor-ring {
  position: fixed;
  left: 0;
  top: 0;
  border-radius: 50%;
  pointer-events: none;
  z-index: 1000;
  opacity: 0;
  transform: translate3d(-50%, -50%, 0);
  transition: opacity .2s ease, width .25s ease, height .25s ease, border-color .25s ease;
  will-change: transform;
}

.cursor-dot {
  width: 8px;
  height: 8px;
  background: var(--olive);
  mix-blend-mode: multiply;
}

.cursor-ring {
  width: 38px;
  height: 38px;
  border: 1px solid rgba(133,172,126,.56);
  backdrop-filter: blur(2px);
}

body.has-cursor .cursor-dot,
body.has-cursor .cursor-ring {
  opacity: 1;
}

body.cursor-active .cursor-ring {
  width: 62px;
  height: 62px;
  border-color: rgba(183,137,143,.76);
}

.motion-reveal {
  will-change: transform, opacity;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: .001ms !important;
  }
}

@media (max-width: 1100px) {
  .cards-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }
  .ch-card,
  .ch-card:nth-child(1),
  .ch-card:nth-child(2),
  .ch-card:nth-child(6n + 1),
  .ch-card:nth-child(6n + 5) {
    grid-column: span 3;
    grid-row: span 1;
    min-height: 230px;
  }
  .quick-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 980px) {
  :root { --sidebar-w: 286px; }
  .main::before {
    left: 0;
  }
  .topbar {
    top: 10px;
    width: min(calc(100% - 24px), var(--maxw));
  }
  .content {
    padding-top: 34px;
  }
}

@media (max-width: 680px) {
  body::before {
    background-size: 54px 54px;
  }
  .topbar {
    gap: 8px;
    padding: 10px;
  }
  .search-wrap {
    max-width: none;
  }
  #searchInput {
    font-size: 13px;
    padding-right: 42px;
  }
  .hero {
    min-height: 430px;
    padding: 28px 22px;
  }
  .hero h1 {
    font-size: clamp(34px, 14vw, 56px);
  }
  .cards-grid,
  .quick-grid {
    grid-template-columns: 1fr;
  }
  .ch-card,
  .ch-card:nth-child(1),
  .ch-card:nth-child(2),
  .ch-card:nth-child(6n + 1),
  .ch-card:nth-child(6n + 5),
  .quick-card {
    grid-column: auto;
    min-height: 190px;
  }
  .q-head,
  .mark-done-bar,
  .pager,
  .tf-btns {
    align-items: stretch;
    flex-direction: column;
  }
  .btn,
  .tf-btn {
    justify-content: center;
    width: 100%;
  }
  .q-hint {
    margin-left: 0;
  }
  .cursor-dot,
  .cursor-ring {
    display: none;
  }
}