/* 法律英语课堂 · 站点外壳：页眉、页脚、首页、讨论单、使用说明、随堂互动。配色变量在 base.css，单元页的样式在 course.css。 */
:root { --en: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Palatino, Georgia, "Noto Serif SC", "Songti SC", serif; --hh: 64px; }
[hidden] { display: none !important; }

/* 页眉 */
.sh { position: sticky; top: 0; z-index: 30; height: var(--hh); background: color-mix(in srgb, var(--paper) 90%, transparent); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--rule); }
.sh-in { height: 100%; display: flex; align-items: center; gap: 24px; }
.mark { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); flex: none; }
.mark i { width: 30px; height: 30px; border-radius: 8px; background: var(--ink); color: var(--paper); display: grid; place-items: center; font: italic 600 19px/1 var(--en); }
.mark b { font: 700 17px/1.1 var(--serif); letter-spacing: .06em; }
.mark small { display: block; font: italic 13px/1.1 var(--en); color: var(--ink-3); letter-spacing: .02em; margin-top: 2px; }
.nav { display: flex; gap: 4px; margin-left: auto; min-width: 0; overflow-x: auto; scrollbar-width: none; }
.nav::-webkit-scrollbar { display: none; }
.nav a { white-space: nowrap; text-decoration: none; color: var(--ink-2); font-size: 15px; padding: 6px 12px; border-radius: 999px; }
.nav a:hover { color: var(--ink); background: var(--paper-2); }
.nav a.on { color: var(--paper); background: var(--ink); }
@media (max-width: 640px) {
  .sh-in { gap: 12px; }
  .mark small { display: none; }
  .mark b { font-size: 15px; }
  .nav a { padding: 6px 9px; font-size: 14px; }
}
@media (max-width: 440px) { .mark span { display: none; } .nav { margin-left: auto; } }

/* 页脚 */
.sf { border-top: 1px solid var(--rule); margin-top: 72px; padding: 28px 0 40px; color: var(--ink-3); font-size: 14px; line-height: 1.7; }
.sf-in { display: flex; justify-content: space-between; gap: 16px 32px; flex-wrap: wrap; }
.sf a { color: inherit; }

/* 通用 */
.eyebrow { font: 700 13px/1 var(--sans); letter-spacing: .26em; text-transform: uppercase; color: var(--accent); }
.lead { color: var(--ink-2); font-size: 18px; line-height: 1.8; max-width: 640px; }
.btn { display: inline-flex; align-items: center; gap: 8px; border-radius: 12px; padding: 11px 20px; font-weight: 600; font-size: 16px; text-decoration: none; border: 1px solid transparent; cursor: pointer; line-height: 1.3; }
.btn.p { background: var(--ink); color: var(--paper); }
.btn.s { background: var(--card); color: var(--ink); border-color: var(--rule); }
.btn.s:hover { border-color: var(--ink-3); }
.btn:disabled { opacity: .45; cursor: default; }
.btn svg { width: 18px; height: 18px; }
.sec { padding-top: 64px; }
.sec-h { display: flex; justify-content: space-between; align-items: end; gap: 12px 24px; flex-wrap: wrap; margin-bottom: 22px; }
.sec-h h2 { margin: 0; font-size: clamp(24px, 3vw, 32px); }
.sec-h p { margin: 6px 0 0; color: var(--ink-2); max-width: 620px; }
.sec-h .more { font-size: 15px; white-space: nowrap; }
.page-h { padding: 52px 0 8px; }
.page-h h1 { font-size: clamp(32px, 4.6vw, 48px); margin: 12px 0 8px; }
.card { background: var(--card); border: 1px solid var(--rule); border-radius: 18px; box-shadow: var(--shadow); }

/* 首页 · 开头 */
.hero { display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(280px, 1fr); gap: 40px; align-items: center; padding: 64px 0 8px; }
.hero h1 { font-size: clamp(34px, 5.2vw, 58px); line-height: 1.15; margin: 16px 0 14px; letter-spacing: .01em; }
.hero h1 em { font-style: normal; color: var(--accent); }
.hero .acts { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 26px; }
.join { padding: 24px; }
.join h2 { margin: 6px 0 4px; font-size: 22px; }
.join p { margin: 0 0 14px; color: var(--ink-2); font-size: 15px; line-height: 1.6; }
.join form { display: flex; gap: 8px; }
.join input { flex: 1; width: 0; min-width: 0; border: 2px solid var(--rule); background: var(--paper); color: var(--ink); border-radius: 12px; padding: 8px 12px; font: 600 28px/1.2 var(--en); letter-spacing: .35em; text-align: center; }
.join input:focus { outline: none; border-color: var(--ink); }
.join .hint { margin-top: 12px; font-size: 13px; color: var(--ink-3); }
.band { padding: 28px 30px; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 20px 32px; align-items: center; }
@media (max-width: 700px) { .band { grid-template-columns: minmax(0, 1fr); padding: 22px; } .band .btn { justify-self: start; } .unit { min-height: 0; } .unit .m { padding-top: 16px; } }
@media (max-width: 820px) { .hero { grid-template-columns: minmax(0, 1fr); gap: 28px; padding-top: 40px; } }

/* 首页 · 三种用法 */
.modes { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0; border: 1px solid var(--rule); border-radius: 18px; overflow: hidden; background: var(--card); }
.modes > div { padding: 20px 22px 22px; border-left: 1px solid var(--rule); }
.modes > div:first-child { border-left: 0; }
.modes .ic { width: 38px; height: 38px; border-radius: 10px; display: grid; place-items: center; background: var(--paper-2); color: var(--c); margin-bottom: 12px; }
.modes .ic svg { width: 20px; height: 20px; }
.modes h3 { margin: 0 0 4px; font-size: 18px; }
.modes p { margin: 0; font-size: 15px; line-height: 1.65; color: var(--ink-2); }
@media (max-width: 900px) { .modes { grid-template-columns: 1fr 1fr; } .modes > div:nth-child(3) { border-left: 0; } .modes > div:nth-child(n+3) { border-top: 1px solid var(--rule); } }
@media (max-width: 520px) { .modes { grid-template-columns: 1fr; } .modes > div { border-left: 0; border-top: 1px solid var(--rule); } .modes > div:first-child { border-top: 0; } }

/* 单元卡 */
.units { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 262px), 1fr)); gap: 14px; }
.unit { position: relative; display: flex; flex-direction: column; gap: 2px; min-height: 212px; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--rule); border-radius: 16px; padding: 18px 20px 16px; transition: transform .15s, box-shadow .15s, border-color .15s; overflow: hidden; }
a.unit:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--ink-3); }
.unit::before { content: ""; position: absolute; inset: 0 0 auto; height: 4px; background: var(--c); }
.unit .n { font: italic 600 15px/1 var(--en); color: var(--c); letter-spacing: .04em; }
.unit .t { font: 600 24px/1.2 var(--en); margin-top: 10px; }
.unit .z { font: 700 16px/1.4 var(--serif); color: var(--ink-2); letter-spacing: .06em; }
.unit .q { font: italic 16px/1.5 var(--en); color: var(--ink-2); margin-top: 10px; }
.unit .m { margin-top: auto; padding-top: 12px; font-size: 13px; color: var(--ink-3); }
.unit.off { background: transparent; border-style: dashed; color: var(--ink-3); }
.unit.off .t, .unit.off .z { color: var(--ink-3); }

/* 讨论单 */
.sheets { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr)); gap: 14px; }
.sheet { display: grid; grid-template-columns: 56px 1fr; gap: 4px 14px; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--rule); border-radius: 16px; padding: 18px 20px; transition: border-color .15s, box-shadow .15s; }
a.sheet:hover { border-color: var(--ink-3); box-shadow: var(--shadow); }
.sheet .no { grid-row: span 3; width: 56px; height: 72px; border-radius: 6px; background: var(--paper); border: 1px solid var(--rule); display: grid; place-items: center; font: italic 600 22px/1 var(--en); color: var(--c, var(--accent)); box-shadow: 3px 3px 0 var(--paper-2); }
.sheet .k { font-size: 13px; color: var(--ink-3); }
.sheet .t { font: 600 19px/1.3 var(--en); }
.sheet .d { font-size: 14px; line-height: 1.6; color: var(--ink-2); }
.sheet .tags { grid-column: 2; display: flex; gap: 6px; flex-wrap: wrap; margin-top: 6px; }
.sheet .tags span { font-size: 12px; border: 1px solid var(--rule); border-radius: 999px; padding: 1px 8px; color: var(--ink-2); }

/* 使用说明 */
.doc { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 48px; align-items: start; }
.doc-toc { position: sticky; top: calc(var(--hh) + 24px); font-size: 15px; }
.doc-toc a { display: block; padding: 5px 0 5px 12px; border-left: 2px solid var(--rule); color: var(--ink-2); text-decoration: none; }
.doc-toc a:hover { color: var(--ink); border-left-color: var(--ink); }
.doc-body { max-width: 760px; }
.doc-body h2 { font-size: 26px; margin: 48px 0 12px; padding-top: 8px; }
.doc-body h2:first-child { margin-top: 0; }
.doc-body h3 { font-size: 19px; margin: 26px 0 8px; }
.doc-body p, .doc-body li { color: var(--ink-2); }
.doc-body li { margin: 4px 0; }
.doc-body kbd { font: 600 13px var(--mono); border: 1px solid var(--rule); border-bottom-width: 2px; border-radius: 6px; padding: 1px 6px; background: var(--card); color: var(--ink); }
.plan { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 15px; background: var(--card); border-radius: 12px; overflow: hidden; border: 1px solid var(--rule); }
.plan th, .plan td { text-align: left; padding: 10px 14px; border-top: 1px solid var(--rule); vertical-align: top; line-height: 1.6; }
.plan th { background: var(--paper-2); border-top: 0; font-weight: 700; color: var(--ink); }
.callout { border-left: 4px solid var(--accent-fill); background: var(--card); border-radius: 0 12px 12px 0; padding: 12px 16px; margin: 16px 0; font-size: 15px; color: var(--ink-2); }
.dl { display: grid; gap: 8px; margin: 14px 0; }
.dl a { display: flex; justify-content: space-between; gap: 12px; align-items: center; text-decoration: none; color: var(--ink); background: var(--card); border: 1px solid var(--rule); border-radius: 12px; padding: 10px 14px; }
.dl a:hover { border-color: var(--ink-3); }
.dl a small { color: var(--ink-3); white-space: nowrap; }
@media (max-width: 820px) { .doc { grid-template-columns: 1fr; gap: 8px; } .doc-toc { position: static; display: flex; flex-wrap: wrap; gap: 4px 14px; } .doc-toc a { border-left: 0; padding: 2px 0; } }

/* 随堂互动 */
.btn.sm { padding: 6px 14px; font-size: 14px; border-radius: 10px; }
.lv { display: grid; grid-template-columns: 320px minmax(0, 1fr); gap: 20px; align-items: start; margin-top: 24px; }
.lv-side { position: sticky; top: calc(var(--hh) + 16px); display: grid; grid-template-columns: minmax(0, 1fr); gap: 16px; }
.lv-main { display: grid; grid-template-columns: minmax(0, 1fr); gap: 20px; min-width: 0; }
.lv .card { padding: 20px 22px; }
.lv h2 { margin: 6px 0 8px; font-size: 22px; }
.lv-room p { color: var(--ink-2); font-size: 15px; line-height: 1.7; }
.lv-fine { font-size: 13px; color: var(--ink-3); line-height: 1.6; margin: 12px 0 0; }
.lv-err { color: var(--g2); font-weight: 600; font-size: 14px; }
.lv-head { display: flex; justify-content: space-between; align-items: end; gap: 16px; flex-wrap: wrap; }
.lv-join { display: grid; grid-template-columns: 116px 1fr; gap: 12px 16px; align-items: center; }
.lv-qr { background: #fff; border-radius: 10px; padding: 6px; }
.lv-qr svg { display: block; width: 100%; height: auto; }
.lv-url { grid-column: 1 / -1; font-size: 14px; color: var(--ink-2); line-height: 1.5; }
.lv-url b { color: var(--ink); font-size: 16px; white-space: nowrap; }
.lv-code { font: 600 50px/1 var(--en); letter-spacing: .1em; }
.lv-on { margin: 14px 0 8px; font-size: 14px; color: var(--ink-2); display: flex; align-items: center; gap: 8px; }
.lv-on .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ink-3); }
.lv-on .dot.ok { background: var(--g4); box-shadow: 0 0 0 3px color-mix(in srgb, var(--g4) 25%, transparent); }
.lv-roster { display: flex; flex-wrap: wrap; gap: 6px; max-height: 210px; overflow: auto; }
.lv-roster span { font-size: 13px; border-radius: 999px; padding: 1px 10px; color: #fff; background: var(--t); }
.lv-roster span.off { opacity: .4; }
.lv-roster .none { background: none; color: var(--ink-3); padding: 0; }
.lv-end { margin-top: 16px; width: 100%; justify-content: center; }
.lv-kinds { display: flex; gap: 4px; background: var(--paper-2); border-radius: 12px; padding: 4px; flex-wrap: wrap; }
.lv-kinds button { flex: 1; border: 0; background: none; border-radius: 9px; padding: 8px 10px; font-weight: 600; font-size: 15px; color: var(--ink-2); cursor: pointer; white-space: nowrap; }
.lv-kinds button.on { background: var(--card); color: var(--ink); box-shadow: 0 1px 3px rgba(0, 0, 0, .12); }
.lv-lab { font-weight: 700; font-size: 14px; margin: 14px 0 6px; display: flex; align-items: baseline; flex-wrap: wrap; }
.lv textarea, .lv input, .lv select { font: inherit; color: var(--ink); background: var(--paper); border: 1.5px solid var(--rule); border-radius: 10px; padding: 8px 12px; }
.lv textarea { width: 100%; font-size: 17px; line-height: 1.5; resize: vertical; }
.lv textarea:focus, .lv input:focus { outline: none; border-color: var(--ink); }
.lv-opts { display: grid; gap: 8px; }
.lv-opt { display: flex; align-items: center; gap: 8px; }
.lv-opt b { flex: none; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; color: #fff; font-size: 14px; }
.lv-opt input { flex: 1; min-width: 0; }
.lv-ok { flex: none; width: 30px; height: 30px; border-radius: 50%; border: 1.5px dashed var(--ink-3); background: none; color: transparent; cursor: pointer; font-weight: 800; }
.lv-ok.on { border: 0; background: var(--g4); color: #fff; }
.lv-x { flex: none; border: 0; background: none; color: var(--ink-3); font-size: 20px; line-height: 1; cursor: pointer; padding: 4px; }
.lv-row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 12px; }
.lv-go { margin-top: 18px; }
.lv-presets { display: flex; flex-wrap: wrap; gap: 8px; }
.lv-presets button { border: 1px solid var(--rule); background: var(--paper); color: var(--ink); border-radius: 10px; padding: 6px 12px; font-size: 14px; cursor: pointer; text-align: left; line-height: 1.35; }
.lv-presets button:hover { border-color: var(--ink-3); }
.lv-presets small { display: block; font-size: 12px; color: var(--ink-3); }
.lv-stage { min-height: 280px; }
.lv-empty { text-align: center; padding: 36px 12px; color: var(--ink-2); }
.lv-empty .big { font: 600 72px/1 var(--en); letter-spacing: .12em; color: var(--ink); margin-bottom: 12px; }
.lv-qhead { display: flex; justify-content: space-between; gap: 12px; align-items: center; flex-wrap: wrap; }
.tag { display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: .04em; border-radius: 999px; padding: 2px 10px; background: var(--paper-2); color: var(--ink-2); margin-right: 8px; }
.lv-code-s { font-size: 14px; color: var(--ink-3); }
.lv-code-s b { color: var(--ink); font-size: 18px; letter-spacing: .08em; }
.lv-qt { font-family: var(--en); font-size: clamp(22px, 2.6vw, 34px) !important; line-height: 1.3; margin: 12px 0 16px !important; }
.lv-timer { height: 8px; border-radius: 999px; background: var(--paper-2); overflow: hidden; margin-bottom: 16px; }
.lv-timer i { display: block; height: 100%; background: linear-gradient(90deg, var(--g2), var(--accent-fill)); transition: width .2s linear; }
.lv-bars { display: grid; gap: 10px; }
.lv-bar { display: grid; grid-template-columns: 34px minmax(0, 1.2fr) minmax(80px, 1fr) 40px; gap: 12px; align-items: center; font-size: 17px; padding: 6px 8px; border-radius: 12px; border: 2px solid transparent; }
.lv-bar b { width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center; color: #fff; }
.lv-bar .track { height: 14px; border-radius: 999px; background: var(--paper-2); overflow: hidden; }
.lv-bar .track i { display: block; height: 100%; border-radius: 999px; transition: width .4s; }
.lv-bar .num { font: 700 20px var(--en); text-align: right; font-variant-numeric: tabular-nums; }
.lv-bar.right { border-color: var(--g4); background: color-mix(in srgb, var(--g4) 12%, transparent); }
.lv-bar.dim { opacity: .45; }
.lv-qfoot { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--rule); color: var(--ink-2); font-size: 15px; }
.lv-wall { display: flex; flex-wrap: wrap; gap: 14px; align-items: flex-start; }
.lv-wait { color: var(--ink-3); }
.lv-note, .lv-card { position: relative; width: min(260px, 100%); padding: 16px 18px 14px; transform: rotate(var(--r)); box-shadow: 0 8px 18px rgba(0, 0, 0, .12); font: 17px/1.5 var(--en); }
.lv-note { background: var(--nc); color: #1b2238; }
.lv-note b { color: #9a530a; }
.lv-note .who { display: block; margin-top: 8px; font: 13px var(--sans); color: #4a5068; }
.lv-card { background: var(--card); border: 1px solid var(--rule); border-radius: 12px; color: var(--ink); }
.lv-note .lv-x, .lv-card .lv-x { position: absolute; top: 2px; right: 4px; opacity: 0; color: inherit; }
.lv-note:hover .lv-x, .lv-card:hover .lv-x { opacity: .6; }
.lv-board { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.lv-board ol { margin: 0; padding-left: 1.4em; }
.lv-board li { display: flex; justify-content: space-between; gap: 8px; padding: 2px 0; }
.lv-board li::marker { color: var(--ink-3); }
.lv-team { display: grid; grid-template-columns: 52px 1fr 52px; gap: 8px; align-items: center; margin: 6px 0; font-size: 15px; }
.lv-team .track { height: 12px; border-radius: 999px; background: var(--paper-2); overflow: hidden; }
.lv-team .track i { display: block; height: 100%; }
.lv-team b { text-align: right; font-variant-numeric: tabular-nums; }
.lv-hist { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; }
.lv-hist button { width: 100%; text-align: left; border: 1px solid var(--rule); background: var(--paper); border-radius: 10px; padding: 8px 12px; cursor: pointer; color: var(--ink); font-size: 15px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lv-hist button:hover { border-color: var(--ink-3); }
.lv-tools { display: flex; gap: 8px; }
@media (max-width: 900px) { .lv { grid-template-columns: minmax(0, 1fr); } .lv-side { position: static; } .lv-board { grid-template-columns: 1fr; } }
@media (max-width: 560px) { .lv-bar { grid-template-columns: 30px 1fr 40px; } .lv-bar .track { grid-column: 2 / 4; grid-row: 2; } .lv-bar b { width: 30px; height: 30px; } }
/* 大屏模式：只留房间号和题目 */
body.lv-big .sh, body.lv-big .sf, body.lv-big .lv-head > div:first-child, body.lv-big #lv-compose, body.lv-big #lv-hist { display: none; }
body.lv-big .lv-head { padding: 0; }
body.lv-big .lv { grid-template-columns: 300px minmax(0, 1fr); margin-top: 16px; }
body.lv-big .lv-side { top: 16px; }
body.lv-big .lv-stage { min-height: calc(100vh - 140px); font-size: 1.15em; }
body.lv-big .lv-bar { font-size: 22px; }
body.lv-big .lv-tools { position: fixed; right: 16px; bottom: 16px; z-index: 40; }