:root {
  --paper: #fbf8f1; --card: #ffffff; --ink: #1f2a44; --ink2: #5a6478; --line: #e6e1d6;
  --accent: #d9482b; --accent-soft: #fbe7e1; --blue: #2c5cc5; --blue-soft: #e6edfb;
  --good: #1f8a4c; --good-soft: #e3f4ea; --warn: #b7791f; --warn-soft: #fbf0dc; --bad: #c0392b;
  --radius: 12px; --shadow: 0 1px 2px rgba(31,42,68,.06), 0 4px 16px rgba(31,42,68,.05);
  --font: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Source Han Sans SC", sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--paper); color: var(--ink); font-family: var(--font); font-size: 16px; line-height: 1.65; }
a { color: var(--blue); text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
h1, h2, h3 { line-height: 1.3; margin: 0 0 .5em; }
h1 { font-size: 1.5rem; } h2 { font-size: 1.2rem; } h3 { font-size: 1.05rem; }

/* 顶栏 */
.topbar { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 16px; padding: 10px 20px;
  background: rgba(251,248,241,.92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.brand { font-weight: 700; letter-spacing: .02em; display: flex; align-items: center; gap: 8px; color: var(--ink); }
.brand .logo { width: 28px; height: 28px; border-radius: 8px; background: var(--ink); color: #fff; display: grid; place-items: center; font-size: 15px; }
.nav { display: flex; gap: 4px; flex: 1; overflow-x: auto; }
.nav a { padding: 6px 12px; border-radius: 8px; color: var(--ink2); white-space: nowrap; }
.nav a.on, .nav a:hover { background: var(--card); color: var(--ink); box-shadow: var(--shadow); }
.who { color: var(--ink2); font-size: .9rem; white-space: nowrap; }
.main { max-width: 1080px; margin: 0 auto; padding: 24px 20px 80px; }
.main.wide { max-width: none; padding: 12px; }

/* 通用 */
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); }
.card + .card { margin-top: 16px; }
.grid { display: grid; gap: 16px; }
.g2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.g3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }
.muted { color: var(--ink2); } .small { font-size: .85rem; }
.btn { display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); cursor: pointer; transition: .15s; white-space: nowrap; }
.btn:hover { border-color: var(--ink2); }
.btn.primary { background: var(--ink); border-color: var(--ink); color: #fff; }
.btn.primary:hover { background: #2d3b5e; }
.btn.red { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.ghost { background: transparent; }
.btn.sm { padding: 4px 10px; font-size: .85rem; border-radius: 8px; }
.btn:disabled { opacity: .45; cursor: not-allowed; }
input.inp, select.inp, textarea.inp { width: 100%; padding: 9px 12px; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
input.inp:focus, select.inp:focus, textarea.inp:focus { outline: 2px solid var(--blue-soft); border-color: var(--blue); }
label.fld { display: block; margin-bottom: 12px; } label.fld > span { display: block; font-size: .85rem; color: var(--ink2); margin-bottom: 4px; }
.tag { display: inline-block; padding: 1px 8px; border-radius: 99px; font-size: .78rem; background: #f1eee6; color: var(--ink2); }
.tag.good { background: var(--good-soft); color: var(--good); } .tag.warn { background: var(--warn-soft); color: var(--warn); }
.tag.bad { background: var(--accent-soft); color: var(--accent); } .tag.blue { background: var(--blue-soft); color: var(--blue); }
.err { color: var(--bad); font-size: .9rem; min-height: 1.4em; }
.empty { text-align: center; color: var(--ink2); padding: 32px 0; }
table.tbl { width: 100%; border-collapse: collapse; font-size: .92rem; }
.tbl th, .tbl td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.tbl th { color: var(--ink2); font-weight: 500; font-size: .82rem; }
.toast { position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%); background: var(--ink); color: #fff; padding: 10px 18px; border-radius: 10px; z-index: 99; box-shadow: var(--shadow); }
.bar { height: 8px; background: #efebe2; border-radius: 99px; overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--blue); border-radius: 99px; }
.bar.good > i { background: var(--good); } .bar.warn > i { background: var(--warn); } .bar.bad > i { background: var(--accent); }

/* 登录 */
.auth { max-width: 420px; margin: 8vh auto; }
.auth .brand { font-size: 1.3rem; justify-content: center; margin-bottom: 20px; }
.seg { display: flex; background: #f1eee6; border-radius: 10px; padding: 3px; margin-bottom: 16px; }
.seg button { flex: 1; border: 0; background: transparent; padding: 7px; border-radius: 8px; cursor: pointer; color: var(--ink2); }
.seg button.on { background: #fff; color: var(--ink); box-shadow: var(--shadow); }

/* 首页 */
.hero { display: flex; gap: 20px; align-items: flex-end; flex-wrap: wrap; margin-bottom: 20px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 18px; min-width: 140px; }
a.stat { display: block; }
.stat b { display: block; font-size: 1.6rem; line-height: 1.2; }
.stat span { color: var(--ink2); font-size: .85rem; }
.rec { border-left: 4px solid var(--accent); }
.live-banner { background: var(--ink); color: #fff; border-radius: var(--radius); padding: 14px 18px; display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
.live-dot { width: 10px; height: 10px; border-radius: 50%; background: #ff4d3a; box-shadow: 0 0 0 0 rgba(255,77,58,.6); animation: pulse 1.6s infinite; flex: none; }
@keyframes pulse { 70% { box-shadow: 0 0 0 10px rgba(255,77,58,0); } 100% { box-shadow: 0 0 0 0 rgba(255,77,58,0); } }
.chapter h2 { margin-top: 8px; }
.section-title { font-weight: 600; color: var(--ink2); font-size: .9rem; margin: 14px 0 8px; }
.kp-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px; }
.kp { display: block; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; background: #fff; color: var(--ink); transition: .15s; }
.kp:hover { border-color: var(--ink2); transform: translateY(-1px); }
.kp .name { font-weight: 600; margin-bottom: 6px; }
.kp .meta { display: flex; justify-content: space-between; align-items: center; gap: 8px; font-size: .8rem; color: var(--ink2); }

/* 讲解页 */
.crumbs { font-size: .85rem; color: var(--ink2); margin-bottom: 8px; }
.kp-head { display: flex; gap: 16px; align-items: flex-start; flex-wrap: wrap; }
.goal { background: var(--blue-soft); border-radius: 10px; padding: 10px 14px; margin: 12px 0; }
.md p { margin: .6em 0; } .md ul, .md ol { padding-left: 1.4em; } .md table { border-collapse: collapse; margin: 10px 0; }
.md td, .md th { border: 1px solid var(--line); padding: 4px 10px; }
.md h3, .md h4 { margin: 1em 0 .4em; }
.md blockquote { margin: .8em 0; padding: 6px 14px; border-left: 3px solid var(--line); color: var(--ink2); }
.md code { background: #f1eee6; padding: 0 4px; border-radius: 4px; }
.steps { counter-reset: st; margin: 10px 0 0; padding: 0; list-style: none; }
.steps li { position: relative; padding: 10px 12px 10px 44px; border: 1px dashed var(--line); border-radius: 10px; margin-bottom: 8px; background: #fffefb; }
.steps li::before { counter-increment: st; content: counter(st); position: absolute; left: 12px; top: 10px; width: 22px; height: 22px; border-radius: 50%; background: var(--ink); color: #fff; font-size: .8rem; display: grid; place-items: center; }
.steps .why { color: var(--accent); font-size: .88rem; margin-top: 4px; }
.pit { background: var(--warn-soft); border-radius: 10px; padding: 10px 14px; margin: 8px 0; }
.toc { position: sticky; top: 70px; }
.toc a { display: block; padding: 4px 0; color: var(--ink2); font-size: .9rem; }

/* 数轴演示 */
.nl-demo svg { width: 100%; height: auto; touch-action: none; user-select: none; }
.nl-readout { display: flex; gap: 18px; flex-wrap: wrap; font-size: 1.05rem; }

/* 练习 */
.q-card { max-width: 760px; margin: 0 auto; }
.q-top { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.progress { flex: 1; }
.q-stem { font-size: 1.12rem; margin: 6px 0 16px; }
.blank { display: inline-block; width: 120px; padding: 3px 8px; margin: 0 4px; border: 0; border-bottom: 2px solid var(--ink); background: #f7f4ec; border-radius: 6px 6px 0 0; text-align: center; font-size: 1.05rem; }
.blank:focus { outline: none; background: var(--blue-soft); border-color: var(--blue); }
.blank.ok { border-color: var(--good); background: var(--good-soft); } .blank.no { border-color: var(--accent); background: var(--accent-soft); }
.opts { display: grid; gap: 10px; }
.opt { display: flex; gap: 12px; align-items: flex-start; padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 10px; cursor: pointer; background: #fff; }
.opt .k { width: 26px; height: 26px; border-radius: 50%; border: 1.5px solid var(--ink2); display: grid; place-items: center; flex: none; font-weight: 600; font-size: .9rem; }
.opt.sel { border-color: var(--blue); background: var(--blue-soft); } .opt.sel .k { background: var(--blue); border-color: var(--blue); color: #fff; }
.opt.right { border-color: var(--good); background: var(--good-soft); } .opt.wrong { border-color: var(--accent); background: var(--accent-soft); }
.keypad { display: flex; flex-wrap: wrap; gap: 6px; margin: 14px 0; }
.keypad button { min-width: 42px; padding: 6px 10px; border: 1px solid var(--line); background: #fff; border-radius: 8px; cursor: pointer; }
.verdict { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.2rem; margin: 16px 0 8px; }
.verdict.ok { color: var(--good); } .verdict.no { color: var(--accent); }
.stamp { font-family: "Kaiti SC", "STKaiti", "KaiTi", serif; }

/* 报告 */
.chart { display: flex; align-items: flex-end; gap: 8px; height: 140px; padding-top: 10px; }
.chart .col { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 4px; font-size: .75rem; color: var(--ink2); }
.chart .col i { width: 100%; max-width: 36px; background: var(--blue); border-radius: 6px 6px 0 0; }
.heat td.h { text-align: center; font-size: .8rem; min-width: 46px; }

/* 画板页面 */
.board-page { display: grid; grid-template-columns: 1fr 340px; gap: 12px; height: calc(100vh - 80px); }
.board-page.solo { grid-template-columns: 1fr; }
.board-col { display: flex; flex-direction: column; gap: 8px; min-width: 0; min-height: 0; }
.board-host { flex: 1; min-height: 0; display: flex; justify-content: center; align-items: flex-start; }
.board-wrap { position: relative; border-radius: 10px; overflow: hidden; box-shadow: var(--shadow); border: 1px solid var(--line); background: #fffdf8; }
.board-canvas { display: block; }
.board-overlay { position: absolute; left: 0; top: 0; width: 1600px; height: 1000px; transform-origin: 0 0; pointer-events: none; }
.board-obj { position: absolute; font-size: 30px; line-height: 1.55; color: var(--ink); background: rgba(230,237,251,.55); border-left: 6px solid var(--blue); padding: 14px 22px; border-radius: 10px; }
.board-obj .katex { font-size: 1.05em; }
.toolbar { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 6px 8px; }
.toolbar .tb { min-width: 36px; height: 36px; padding: 0 9px; border-radius: 8px; border: 1px solid transparent; background: transparent; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; gap: 4px; font-size: .9rem; }
.toolbar .tb:hover { background: #f4f1ea; } .toolbar .tb.on { background: var(--ink); color: #fff; }
.toolbar .sep { width: 1px; height: 24px; background: var(--line); margin: 0 4px; }
.sw { width: 22px; height: 22px; border-radius: 50%; border: 2px solid #fff; box-shadow: 0 0 0 1px var(--line); cursor: pointer; }
.sw.on { box-shadow: 0 0 0 2px var(--ink); }
.side { display: flex; flex-direction: column; gap: 10px; overflow-y: auto; min-height: 0; }
.side .card { padding: 14px; }
.side .card + .card { margin-top: 0; }
.clock { font-variant-numeric: tabular-nums; font-size: 1.6rem; font-weight: 700; }
.roster li { display: flex; justify-content: space-between; align-items: center; padding: 4px 0; }
.roster, .asks { list-style: none; margin: 0; padding: 0; max-height: 220px; overflow-y: auto; }
.asks li { padding: 6px 0; border-bottom: 1px dashed var(--line); font-size: .9rem; }
.pager { display: flex; gap: 6px; align-items: center; }
.live-status { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; }
.mic-meter { height: 6px; width: 100%; background: #efebe2; border-radius: 99px; overflow: hidden; } .mic-meter i { display: block; height: 100%; width: 0; background: var(--good); transition: width .08s; }
.modal-bg { position: fixed; inset: 0; background: rgba(20,24,36,.4); display: grid; place-items: center; z-index: 60; padding: 16px; }
.modal { background: #fff; border-radius: 14px; padding: 20px; width: min(640px, 100%); max-height: 90vh; overflow-y: auto; box-shadow: 0 20px 60px rgba(0,0,0,.2); }
.timeline { position: relative; height: 34px; cursor: pointer; }
.timeline .track { position: absolute; left: 0; right: 0; top: 14px; height: 6px; background: #e8e3d8; border-radius: 99px; }
.timeline .fill { position: absolute; left: 0; top: 14px; height: 6px; background: var(--accent); border-radius: 99px; }
.timeline .mark { position: absolute; top: 6px; width: 3px; height: 22px; background: var(--ink); border-radius: 2px; opacity: .55; }
.timeline .knob { position: absolute; top: 9px; width: 16px; height: 16px; margin-left: -8px; border-radius: 50%; background: #fff; border: 3px solid var(--accent); }
.player-bar { display: flex; gap: 10px; align-items: center; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 8px 12px; }
.player-bar .timeline { flex: 1; }

/* 备课区 */
.prep-layout { display: grid; grid-template-columns: 270px 1fr; gap: 16px; align-items: start; }
.prep-tree { position: sticky; top: 70px; max-height: calc(100vh - 90px); overflow-y: auto; padding: 16px; }
.prep-sec { display: flex; justify-content: space-between; align-items: center; gap: 6px; padding: 6px 8px; border-radius: 8px; color: var(--ink); font-size: .92rem; }
.prep-sec .tag { white-space: nowrap; }
.prep-sec:hover { background: #f4f1ea; } .prep-sec.on { background: var(--blue-soft); font-weight: 600; }
.prep-layout > section .card:first-child { margin-top: 0; }
.prep-kp { border-top: 1px dashed var(--line); padding: 8px 0; } .prep-kp summary { cursor: pointer; display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.prep-card { border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; margin-bottom: 10px; background: #fffefb; }
.prep-body { margin-top: 6px; } .prep-body.clip { max-height: 170px; overflow: hidden; -webkit-mask-image: linear-gradient(#000 70%, transparent); mask-image: linear-gradient(#000 70%, transparent); }
#tabPrep { padding: 12px; } .pp-card { border-bottom: 1px dashed var(--line); padding: 8px 0; font-size: .9rem; }
.pp-card summary { cursor: pointer; } .pp-card .md { margin: 6px 0; } .pp-card .md p { margin: .4em 0; }
#sideTabs { flex: none; }

/* 图形 */
.fig { margin: 8px 0; } .fig svg { display: block; background: #fff; border-radius: 8px; }
.q-stem .fig svg { border: 1px solid var(--line); }
.board-obj .fig svg { background: transparent; }

/* 互动演示 */
.demo { display: flex; gap: 16px; flex-wrap: wrap; align-items: flex-start; }
.demo-fig { flex: 1 1 360px; max-width: 480px; user-select: none; cursor: grab; }
.demo-fig svg { width: 100%; border: 1px solid var(--line); }
.demo-side { flex: 1 1 220px; display: flex; flex-direction: column; gap: 8px; }
.demo-kv { display: flex; flex-direction: column; gap: 6px; font-size: .95rem; }
.demo-kv span { background: #fffefb; border: 1px solid var(--line); border-radius: 8px; padding: 5px 10px; }
.demo-sl { display: block; font-size: .9rem; } .demo-sl input { width: 100%; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }
.fn-row { display: flex; gap: 6px; align-items: center; margin-bottom: 6px; } .fn-row .sw { flex: none; cursor: default; }

/* 预习 */
.pv-road { position: relative; }
.pv-ch { font-weight: 700; color: var(--ink2); margin: 14px 0 6px 44px; font-size: .9rem; }
.pv-node { display: flex; gap: 14px; position: relative; padding-bottom: 14px; }
.pv-node::before { content: ""; position: absolute; left: 15px; top: 34px; bottom: 0; width: 2px; background: var(--line); }
.pv-dot { width: 32px; height: 32px; border-radius: 50%; flex: none; display: grid; place-items: center; font-weight: 700; font-size: .9rem; border: 2px solid var(--line); background: #fff; color: var(--ink2); z-index: 1; }
.pv-node.done .pv-dot { background: var(--good); border-color: var(--good); color: #fff; }
.pv-node.doing .pv-dot { border-color: var(--blue); color: var(--blue); }
.pv-node.next .pv-dot { box-shadow: 0 0 0 4px var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.pv-body { flex: 1; min-width: 0; border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; background: #fff; }
.pv-node.next .pv-body { border-color: var(--accent); }
.pv-stepper { display: flex; gap: 6px; flex-wrap: wrap; margin: 14px 0; position: sticky; top: 58px; z-index: 5; background: var(--paper); padding: 6px 0; }
.pv-step { display: inline-flex; align-items: center; gap: 6px; padding: 5px 12px 5px 6px; border: 1px solid var(--line); border-radius: 99px; background: #fff; color: var(--ink2); font-size: .88rem; }
.pv-step span { width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center; background: #efebe2; font-size: .78rem; font-weight: 700; }
.pv-step.ok { color: var(--good); border-color: var(--good); } .pv-step.ok span { background: var(--good); color: #fff; }
.pv-read { border-top: 1px dashed var(--line); padding: 12px 0; }
.pv-ex { background: #fffefb; border: 1px dashed var(--line); border-radius: 10px; padding: 10px 14px; margin: 10px 0; }
.pv-doubt { border-top: 1px dashed var(--line); padding: 6px 0; }
.pv-reply { background: var(--good-soft); border-radius: 8px; padding: 6px 10px; margin-top: 4px; }
.pv-bar { display: flex; height: 8px; background: #efebe2; border-radius: 99px; overflow: hidden; margin-top: 6px; }
.pv-bar i { display: block; height: 100%; } .pv-bar i.good { background: var(--good); } .pv-bar i.blue { background: var(--blue); } .pv-bar i.warn { background: var(--warn); } .pv-bar i.bad { background: var(--accent); }
.btn.good-btn { border-color: var(--good); color: var(--good); }

@media (max-width: 900px) {
  .prep-layout { grid-template-columns: 1fr; } .prep-tree { position: static; max-height: none; }
  .board-page { grid-template-columns: 1fr; height: auto; }
  .board-host { flex: none; min-height: 0; }
  .topbar { padding: 8px 12px; gap: 10px; } .who { display: none; }
  .main { padding: 16px 12px 60px; }
}
@media print {
  .topbar, .noprint { display: none !important; }
  body { background: #fff; } .card { box-shadow: none; border: 0; padding: 0; }
  .print-item { page-break-inside: avoid; border-bottom: 1px solid #ccc; padding: 10px 0; }
}
.board-obj.board-fig { background: transparent; border-left: 0; padding: 8px; pointer-events: none; }  /* 透明：老师可以在图上批注 */
.board-obj.board-fig svg { width: 100%; height: auto; display: block; }
.board-prot { position: absolute; z-index: 2; transform-origin: 304px 304px; pointer-events: none; user-select: none; }
.board-prot svg { display: block; overflow: visible; }
.board-prot text.in { font-size: 13px; }
.fig-grab { position: absolute; left: -14px; top: -14px; width: 30px; height: 30px; border-radius: 50%; background: #2c5cc5; color: #fff; font-size: 18px; line-height: 30px; text-align: center; cursor: move; pointer-events: auto; box-shadow: 0 1px 4px rgba(0,0,0,.25); }
.fn-row > span.small { white-space: nowrap; }
.tb-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 6px; }
.tb-opt { margin: 0 !important; padding: 8px 10px !important; }
pre.mcode { font-family: "SFMono-Regular", Menlo, Consolas, "Courier New", monospace; font-size: 1rem; line-height: 1.35; background: #fbf8f1; border: 1px solid var(--line); border-radius: 8px; padding: 10px 14px; display: inline-block; margin: 6px 0; white-space: pre; overflow-x: auto; max-width: 100%; }
/* v0.9 答疑 / 自学课程 */
.nav a .badge { display: inline-block; min-width: 18px; height: 18px; line-height: 18px; padding: 0 5px; margin-left: 4px; border-radius: 9px; background: var(--accent); color: #fff; font-size: 12px; text-align: center; }
.qa-card { border-left: 4px solid var(--line); }
.qa-card.unseen { border-left-color: var(--accent); }
.qa-thread { margin-top: 8px; display: flex; flex-direction: column; gap: 6px; }
.qa-msg { padding: 8px 12px; border-radius: 10px; background: #f6f2e8; max-width: 92%; }
.qa-msg.teacher { background: var(--blue-soft); align-self: flex-end; }
.qa-q { background: #fbf8f1; border: 1px dashed var(--line); border-radius: 8px; padding: 6px 10px; margin-top: 6px; }
.course-unit summary { cursor: pointer; list-style: none; }
.course-unit summary::-webkit-details-marker { display: none; }
.course-unit.done { opacity: .85; }
.course-kp { display: flex; align-items: center; gap: 8px; padding: 6px 4px; border-bottom: 1px dashed var(--line); flex-wrap: wrap; }
.course-kp .ck-dot { width: 22px; height: 22px; border-radius: 50%; border: 2px solid var(--line); display: inline-flex; align-items: center; justify-content: center; font-size: 13px; flex: none; }
.course-kp.passed .ck-dot { background: var(--good); border-color: var(--good); color: #fff; }
.course-kp.practice .ck-dot { border-color: var(--warn, #b7791f); color: var(--warn, #b7791f); }
.card.locked { opacity: .7; }
.ring { flex: none; }
.cert { background: #fff; border: 10px double #b7791f; padding: 8px; margin: 16px auto; max-width: 760px; }
.cert-in { border: 1px solid #e3cf9c; padding: 36px 40px; text-align: center; }
.cert-logo { color: #b7791f; font-weight: 700; letter-spacing: 2px; }
.cert h1 { font-size: 2.2rem; letter-spacing: 12px; margin: 10px 0 18px; }
.cert-name { font-size: 1.8rem; font-weight: 700; border-bottom: 2px solid var(--ink); display: inline-block; padding: 0 24px 4px; }
.cert-course { font-size: 1.3rem; font-weight: 700; color: var(--blue); }
.cert-tbl { max-width: 420px; margin: 12px auto; }
@media print { .cert { border-width: 8px; margin: 0 auto; } }
.grid > .card { margin-top: 0; margin-bottom: 0; }
.install-steps { display: grid; gap: 10px; margin: 10px 0; }
.install-steps > div { border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; }
.install-steps > div.on { border-color: var(--blue); background: var(--blue-soft); }
.install-steps ol { margin: 6px 0 0 18px; padding: 0; }
@media (display-mode: standalone) { .topbar { padding-top: max(10px, env(safe-area-inset-top)); } }
/* 学习方法页 */
.methods-hero { background: linear-gradient(135deg, #1f2a44, #2c5cc5); color: #fff; }
.methods-hero .muted, .methods-hero p { color: rgba(255,255,255,.85) !important; }
.methods-hero .stat b, .methods-hero .stat span { color: #fff; }
.why-card { background: #fbf8f1; border-radius: 10px; padding: 12px 14px; }
.why-card p { margin: 6px 0 0; color: var(--ink2); }
.story { border-left: 4px solid #b7791f; padding: 4px 12px; }
.story-n { font-weight: 700; font-size: 1.05rem; }
.story p { margin: 6px 0 0; color: var(--ink2); font-size: .95rem; }
.methods { display: grid; gap: 8px; }
.method { border: 1px solid var(--line); border-radius: 12px; padding: 10px 14px; background: #fff; }
.method[open] { border-color: var(--blue); box-shadow: var(--shadow); }
.method summary { display: flex; gap: 12px; align-items: center; cursor: pointer; list-style: none; }
.method summary::-webkit-details-marker { display: none; }
.method .m-i { width: 34px; height: 34px; border-radius: 50%; background: var(--blue-soft); color: var(--blue); display: inline-flex; align-items: center; justify-content: center; font-weight: 700; flex: none; }
.method .m-h { font-weight: 600; margin-bottom: 4px; }
.method ol, .method ul { margin: 0 0 8px 18px; padding: 0; }
.pledges { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 6px; margin-bottom: 10px; }
.pledges .opt { margin: 0; padding: 6px 10px; }
.pledge-show { background: #fbf8f1; border: 1px dashed #b7791f; border-radius: 10px; padding: 12px 16px; }
.g2x { grid-template-columns: 1fr 1fr; }
@media (max-width: 700px) { .g2x { grid-template-columns: 1fr; } }
.methods-hero .stat { background: rgba(255,255,255,.14); box-shadow: none; }
.methods-hero { padding: 22px 26px; border-radius: 16px; }
@media (max-width: 700px) {
  .topbar { flex-wrap: wrap; row-gap: 6px; }
  .topbar .nav { order: 3; flex-basis: 100%; }
  .topbar .who { display: inline; font-size: .8rem; margin-left: auto; }
  #installApp { padding: 4px 8px; }
}
.acct { position: relative; }
.acct .who { cursor: pointer; }
.acct-menu { display: none; position: absolute; right: 0; top: calc(100% + 6px); background: var(--card, #fff); border: 1px solid var(--line); border-radius: 10px; box-shadow: var(--shadow); min-width: 170px; padding: 4px 0; z-index: 30; }
.acct-menu.open { display: block; }
.acct-menu button, .acct-menu a { display: block; width: 100%; text-align: left; padding: 8px 12px; background: none; border: 0; font: inherit; color: var(--ink); cursor: pointer; }
.acct-menu button:hover, .acct-menu a:hover { background: var(--blue-soft); }