:root {
  --paper: #f4f0e8;
  --paper-deep: #e9e2d6;
  --ink: #1d2624;
  --muted: #76807c;
  --faint: #aeb6b0;
  --line: rgba(29,38,36,.13);
  --line-strong: rgba(29,38,36,.25);
  --accent: #c94a39;
  --accent-deep: #a83a2e;
  --jade: #48776d;
  --yellow: #e8b94e;
  --card: rgba(255,253,248,.72);
  --shadow: 0 18px 50px rgba(39,36,28,.08);
  --radius: 18px;
  --serif: Georgia, "Noto Serif SC", "Songti SC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}
:root.dark {
  --paper: #1b211f; --paper-deep: #232c29; --ink: #f4f0e8; --muted: #9eaaa3; --faint: #6f7b74;
  --line: rgba(244,240,232,.13); --line-strong: rgba(244,240,232,.25); --card: rgba(33,42,39,.9);
  --shadow: 0 18px 50px rgba(0,0,0,.25); --accent: #e56a57; --jade: #77a99e;
}
* { box-sizing: border-box; }
html { min-width: 320px; background: var(--paper); color: var(--ink); }
body { margin: 0; font-family: var(--sans); background: var(--paper); color: var(--ink); min-height: 100vh; }
button, input, select { font: inherit; color: inherit; }
button { cursor: pointer; }
.grain { position: fixed; inset: 0; pointer-events: none; opacity: .14; z-index: 0; background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.12'/%3E%3C/svg%3E"); }
.topbar { position: sticky; top: 0; z-index: 20; height: 78px; padding: 0 clamp(20px, 5vw, 72px); display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); background: color-mix(in srgb, var(--paper) 88%, transparent); backdrop-filter: blur(14px); }
.brand { display: flex; gap: 12px; align-items: center; text-decoration: none; color: var(--ink); min-width: 205px; }
.brand-mark { width: 35px; height: 35px; display: grid; place-items: center; border: 1.5px solid var(--ink); font: 700 11px/1 var(--sans); letter-spacing: -.08em; transform: rotate(-7deg); }
.brand strong { display: block; font: 700 16px/1.1 var(--serif); letter-spacing: .05em; }
.brand small { display: block; font-size: 8px; letter-spacing: .18em; color: var(--muted); margin-top: 4px; }
.nav-tabs { display: flex; gap: 28px; align-self: stretch; align-items: center; }
.nav-tab { border: 0; background: none; color: var(--muted); height: 100%; position: relative; font-size: 13px; padding: 0 2px; }
.nav-tab:hover, .nav-tab.active { color: var(--ink); }
.nav-tab.active::after { content: ""; position: absolute; height: 2px; background: var(--accent); left: 0; right: 0; bottom: 0; }
.nav-tab b { font-size: 10px; padding: 2px 5px; margin-left: 3px; background: var(--paper-deep); color: var(--muted); border-radius: 10px; }
.icon-button { border: 1px solid var(--line); background: transparent; height: 34px; width: 34px; border-radius: 50%; display: grid; place-items: center; color: var(--muted); font-size: 18px; }
.icon-button:hover { border-color: var(--accent); color: var(--accent); }
.page { position: relative; z-index: 1; max-width: 1400px; margin: 0 auto; padding: 62px clamp(20px, 5vw, 72px) 90px; }
.view { display: none; animation: rise .35s ease both; }
.view.active { display: block; }
@keyframes rise { from { opacity: 0; transform: translateY(7px); } to { opacity: 1; transform: none; } }
.intro-row { min-height: 335px; display: grid; grid-template-columns: 1fr 330px; gap: 80px; align-items: center; }
.eyebrow { color: var(--accent); font-size: 10px; letter-spacing: .16em; font-weight: 700; }
.pulse-dot { display: inline-block; width: 7px; height: 7px; border-radius: 50%; background: var(--accent); margin-right: 7px; box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 15%, transparent); }
h1 { font: 400 clamp(46px, 6vw, 82px)/.98 var(--serif); letter-spacing: -.06em; margin: 18px 0 20px; }
h1 em { color: var(--accent); font-style: normal; position: relative; }
h1 em::after { content: ""; height: 4px; position: absolute; left: 0; right: -8px; bottom: -3px; background: var(--yellow); transform: rotate(-2deg); z-index: -1; }
.intro-copy > p { color: var(--muted); max-width: 450px; font-size: 15px; line-height: 1.8; margin: 0 0 25px; }
.intro-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.button { border: 1px solid var(--line-strong); background: transparent; min-height: 42px; padding: 0 17px; border-radius: 5px; font-size: 13px; transition: .2s; }
.button:hover { border-color: var(--ink); transform: translateY(-1px); }
.button.primary { background: var(--ink); color: var(--paper); border-color: var(--ink); box-shadow: 4px 4px 0 color-mix(in srgb, var(--accent) 55%, transparent); }
.button.primary:hover { background: var(--accent); border-color: var(--accent); }
.button.quiet { color: var(--muted); border-color: transparent; }
.button.small { min-height: 34px; padding: 0 12px; font-size: 12px; }
.button span { margin-left: 11px; color: var(--yellow); }
.desk-card { background: var(--card); border: 1px solid var(--line); padding: 20px; border-radius: var(--radius); box-shadow: var(--shadow); transform: rotate(2deg); }
.desk-card-top, .desk-card-foot { display: flex; justify-content: space-between; align-items: center; font-size: 11px; color: var(--muted); }
.live-label { color: var(--jade); letter-spacing: .12em; font-size: 8px; }
.ring-wrap { display: grid; place-items: center; padding: 25px 0 23px; }
.progress-ring { --progress: 0%; width: 160px; height: 160px; border-radius: 50%; display: grid; place-items: center; background: conic-gradient(var(--accent) var(--progress), var(--paper-deep) 0); position: relative; }
.progress-ring::before { content: ""; position: absolute; inset: 9px; background: var(--card); border-radius: 50%; }
.progress-ring > div { position: relative; text-align: center; }
.progress-ring strong { font: 400 44px/1 var(--serif); display: block; }
.progress-ring small { color: var(--muted); font-size: 11px; }
.desk-card-foot { padding-top: 14px; border-top: 1px solid var(--line); }
.desk-card-foot b { color: var(--ink); margin-left: 5px; }
.stat-strip { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); display: grid; grid-template-columns: repeat(4,1fr); padding: 23px 0; margin: 32px 0 62px; }
.stat-strip > div { padding: 0 24px; border-right: 1px solid var(--line); }
.stat-strip > div:first-child { padding-left: 0; }
.stat-strip > div:last-child { border: 0; }
.stat-label { display: block; color: var(--muted); font-size: 10px; letter-spacing: .08em; margin-bottom: 8px; }
.stat-strip strong { font: 400 28px/1 var(--serif); margin-right: 6px; }
.stat-strip small { color: var(--muted); font-size: 11px; }
.section-heading { display: flex; justify-content: space-between; align-items: end; gap: 20px; margin-bottom: 24px; }
.section-heading h2 { font: 400 32px/1 var(--serif); letter-spacing: -.04em; margin: 8px 0 0; }
.section-heading h3 { font: 400 22px/1 var(--serif); margin: 8px 0 0; }
.section-note { color: var(--muted); font-size: 12px; }
.library-layout { display: grid; grid-template-columns: 220px 1fr; gap: 35px; align-items: start; }
.filter-rail { border-right: 1px solid var(--line); padding-right: 25px; }
.filter-label { color: var(--muted); font-size: 10px; letter-spacing: .14em; text-transform: uppercase; margin-bottom: 13px; }
.filter-rail label { display: block; font-size: 11px; color: var(--muted); margin-bottom: 17px; }
.filter-rail select, .search-field input { display: block; width: 100%; border: 0; border-bottom: 1px solid var(--line-strong); background: transparent; padding: 9px 0; outline: 0; font-size: 13px; color: var(--ink); }
.filter-rail select:focus, .search-field input:focus { border-color: var(--accent); }
.search-field { display: flex !important; gap: 8px; align-items: center; border-bottom: 1px solid var(--line-strong); }
.search-field span { color: var(--muted); font-size: 20px; }
.search-field input { border: 0; }
.quick-filter { border-top: 1px solid var(--line); margin-top: 28px; padding-top: 20px; }
.quick-filter button { display: flex; justify-content: space-between; width: 100%; border: 0; background: none; color: var(--muted); padding: 8px 0; font-size: 12px; text-align: left; }
.quick-filter button:hover { color: var(--accent); }
.quick-filter b { font-weight: 400; }
.privacy-note { display: flex; gap: 8px; margin-top: 40px; color: var(--muted); font-size: 10px; line-height: 1.6; }
.privacy-note span { color: var(--jade); font-size: 18px; }
.privacy-note strong { color: var(--ink); font-weight: 500; }
.browser-head { display: flex; justify-content: space-between; align-items: end; margin-bottom: 18px; }
.browser-head h3 { font: 400 24px var(--serif); margin: 7px 0 0; }
.result-count { font-size: 11px; color: var(--muted); }
.paper-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 12px; min-height: 430px; }
.paper-card { min-height: 150px; border: 1px solid var(--line); background: var(--card); border-radius: 12px; padding: 17px 18px; cursor: pointer; transition: .22s; position: relative; overflow: hidden; }
.paper-card::after { content: "→"; position: absolute; right: 17px; bottom: 15px; color: var(--faint); transition: .2s; }
.paper-card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: var(--shadow); }
.paper-card:hover::after { color: var(--accent); transform: translateX(3px); }
.paper-card .paper-meta { display: flex; gap: 7px; color: var(--muted); font-size: 10px; margin-bottom: 13px; }
.module-chip { color: var(--jade); }
.paper-card h4 { font: 500 15px/1.45 var(--serif); margin: 0 25px 10px 0; max-width: 360px; }
.paper-card .paper-foot { color: var(--muted); font-size: 11px; }
.loading-card { grid-column: 1/-1; display: grid; place-content: center; gap: 16px; color: var(--muted); font: 15px var(--serif); text-align: center; }
.loading-line { display: block; height: 1px; width: 130px; background: linear-gradient(90deg,transparent,var(--accent),transparent); animation: load 1.2s infinite; }
@keyframes load { from { transform: translateX(-60px); opacity: .2; } to { transform: translateX(60px); opacity: .9; } }
.pagination { display: flex; align-items: center; justify-content: center; gap: 18px; margin-top: 24px; color: var(--muted); font-size: 11px; }
.page-heading { margin-bottom: 38px; }
.practice-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 20px; margin-bottom: 16px; }
.back-link { border: 0; background: none; padding: 0; color: var(--muted); font-size: 12px; }
.back-link:hover { color: var(--accent); }
.session-title { text-align: center; }
.session-title span { display: block; color: var(--accent); font-size: 10px; letter-spacing: .1em; }
.session-title strong { display: block; font: 400 18px var(--serif); margin-top: 4px; }
.session-tools { min-width: 100px; display: flex; justify-content: end; gap: 12px; align-items: center; }
.timer { font: 12px ui-monospace, SFMono-Regular, Menlo, monospace; color: var(--muted); }
.practice-progress { height: 3px; width: 100%; background: var(--paper-deep); margin-bottom: 30px; }
.practice-progress div { height: 100%; width: 0; background: var(--accent); transition: width .25s; }
.practice-layout { display: grid; grid-template-columns: 190px 1fr; gap: 35px; max-width: 1100px; margin: 0 auto; }
.question-map-panel { padding-top: 12px; }
.map-head { display: flex; justify-content: space-between; font-size: 11px; color: var(--muted); padding-bottom: 13px; border-bottom: 1px solid var(--line); }
.map-head small { color: var(--ink); }
.question-map { display: grid; grid-template-columns: repeat(5, 1fr); gap: 7px; padding: 16px 0; max-height: 430px; overflow: auto; }
.map-dot { width: 28px; height: 28px; border: 1px solid var(--line-strong); border-radius: 50%; display: grid; place-items: center; background: transparent; color: var(--muted); font-size: 10px; }
.map-dot:hover { border-color: var(--accent); color: var(--accent); }
.map-dot.current { border: 2px solid var(--accent); color: var(--accent); }
.map-dot.answered { background: var(--ink); border-color: var(--ink); color: var(--paper); }
.map-dot.wrong { background: color-mix(in srgb, var(--accent) 18%, transparent); border-color: var(--accent); color: var(--accent); }
.map-dot.current.answered { outline: 3px solid color-mix(in srgb, var(--accent) 30%, transparent); }
.map-legend { display: grid; gap: 8px; color: var(--muted); font-size: 10px; }
.map-legend span { display: flex; align-items: center; gap: 7px; }
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--paper-deep); border: 1px solid var(--line-strong); }
.dot.answered { background: var(--ink); border: 0; }.dot.wrong { background: var(--accent); border: 0; }
.question-card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: clamp(24px, 4vw, 50px); min-height: 550px; }
.question-meta { display: flex; justify-content: space-between; gap: 12px; align-items: center; color: var(--muted); font-size: 11px; margin-bottom: 29px; }
.question-meta .question-tag { color: var(--jade); }.question-meta .qid { font: 10px ui-monospace, monospace; color: var(--faint); }
.material { border-left: 2px solid var(--yellow); padding: 12px 17px; margin-bottom: 28px; color: var(--muted); font-size: 13px; line-height: 1.85; background: color-mix(in srgb, var(--yellow) 6%, transparent); max-height: 280px; overflow: auto; }
.question-stem { font: 500 clamp(18px, 2.3vw, 24px)/1.72 var(--serif); letter-spacing: .01em; margin-bottom: 28px; }
.question-stem p:first-child, .material p:first-child { margin-top: 0; }.question-stem p:last-child, .material p:last-child { margin-bottom: 0; }
.question-stem img, .material img, .option-text img, .explanation img { max-width: 100%; height: auto; vertical-align: middle; }
.option-list { display: grid; gap: 10px; }
.option-button { width: 100%; display: flex; gap: 14px; align-items: flex-start; text-align: left; border: 1px solid var(--line); background: transparent; padding: 15px 16px; border-radius: 8px; transition: .2s; line-height: 1.6; }
.option-button:hover:not(:disabled) { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 5%, transparent); }
.option-key { flex: 0 0 25px; height: 25px; display: grid; place-items: center; border: 1px solid var(--line-strong); border-radius: 50%; color: var(--muted); font-size: 11px; }
.option-text { font-size: 14px; flex: 1; }.option-button.selected { border-color: var(--ink); }.option-button.correct { border-color: var(--jade); background: color-mix(in srgb, var(--jade) 9%, transparent); }.option-button.wrong { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 9%, transparent); }.option-button.correct .option-key { background: var(--jade); border-color: var(--jade); color: white; }.option-button.wrong .option-key { background: var(--accent); border-color: var(--accent); color: white; }
.feedback { margin-top: 22px; padding: 14px 16px; display: flex; gap: 10px; align-items: flex-start; border-radius: 7px; font-size: 13px; line-height: 1.7; }.feedback.good { background: color-mix(in srgb, var(--jade) 10%, transparent); color: var(--jade); }.feedback.bad { background: color-mix(in srgb, var(--accent) 10%, transparent); color: var(--accent); }
.explanation-wrap { border-top: 1px solid var(--line); margin-top: 26px; padding-top: 19px; }.explanation-toggle { border: 0; background: none; color: var(--jade); padding: 0; font-size: 12px; }.explanation { color: var(--muted); font-size: 13px; line-height: 1.9; margin-top: 14px; }.explanation strong { color: var(--ink); }
.question-footer { border-top: 1px solid var(--line); margin-top: 32px; padding-top: 19px; display: flex; justify-content: space-between; align-items: center; }.question-footer small { color: var(--muted); font-size: 11px; }.nav-actions { display: flex; gap: 9px; }.empty-practice { min-height: 440px; display: grid; place-items: center; color: var(--muted); font: 18px var(--serif); text-align: center; }
.mistake-toolbar { border-bottom: 1px solid var(--line); padding-bottom: 16px; display: flex; justify-content: space-between; color: var(--muted); font-size: 12px; margin-bottom: 20px; }.mistake-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 13px; }.mistake-card { border: 1px solid var(--line); background: var(--card); padding: 18px; border-radius: 10px; cursor: pointer; }.mistake-card:hover { border-color: var(--accent); }.mistake-card small { color: var(--muted); }.mistake-card h4 { font: 500 15px/1.5 var(--serif); margin: 12px 0 20px; }.mistake-card p { color: var(--muted); font-size: 11px; margin: 0; }.empty-state { grid-column: 1/-1; text-align: center; padding: 90px 20px; color: var(--muted); }.empty-state > span { font: 40px var(--serif); color: var(--yellow); }.empty-state h3 { color: var(--ink); font: 400 25px var(--serif); margin: 16px 0 9px; }.empty-state p { font-size: 12px; margin-bottom: 22px; }
.record-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 14px; }.record-card { min-height: 185px; border: 1px solid var(--line); border-radius: 12px; background: var(--card); padding: 22px; }.record-card.featured { background: var(--ink); color: var(--paper); }.record-card strong { display: block; font: 400 50px/1 var(--serif); margin: 18px 0 10px; }.record-card p { color: var(--muted); font-size: 11px; margin: 0; }.featured p { color: color-mix(in srgb, var(--paper) 60%, transparent); }.mini-bars { height: 45px; display: flex; align-items: end; gap: 4px; margin-top: 18px; }.mini-bars i { width: 9px; background: var(--yellow); opacity: .8; border-radius: 2px 2px 0 0; }.sub-heading { margin-top: 55px; }.module-performance { display: grid; gap: 13px; max-width: 760px; }.module-row { display: grid; grid-template-columns: 160px 1fr 70px; gap: 15px; align-items: center; font-size: 12px; }.module-row span:first-child { color: var(--muted); }.bar { height: 7px; border-radius: 10px; background: var(--paper-deep); overflow: hidden; }.bar i { display: block; height: 100%; background: var(--jade); border-radius: inherit; }.module-row b { text-align: right; font-weight: 500; }
.toast { position: fixed; z-index: 50; left: 50%; bottom: 24px; transform: translate(-50%, 20px); opacity: 0; pointer-events: none; background: var(--ink); color: var(--paper); padding: 11px 17px; border-radius: 5px; font-size: 12px; transition: .25s; box-shadow: var(--shadow); }.toast.show { opacity: 1; transform: translate(-50%,0); }
@media (max-width: 900px) { .intro-row { grid-template-columns: 1fr 260px; gap: 30px; } .library-layout { grid-template-columns: 180px 1fr; gap: 20px; } .paper-grid { grid-template-columns: 1fr; }.practice-layout { grid-template-columns: 150px 1fr; gap: 20px; } }
@media (max-width: 680px) { .topbar { height: 64px; padding: 0 16px; }.brand { min-width: auto; }.brand small { display: none; }.nav-tabs { gap: 14px; }.nav-tab { font-size: 11px; }.nav-tab b { display: none; }.icon-button { width: 31px; height: 31px; }.page { padding: 35px 16px 70px; }.intro-row { display: block; min-height: auto; }.intro-copy > p { font-size: 13px; }.desk-card { max-width: 280px; margin: 38px auto 0; }.stat-strip { grid-template-columns: repeat(2,1fr); gap: 18px 0; margin: 43px 0; }.stat-strip > div { padding: 0 12px; }.stat-strip > div:nth-child(3) { padding-left: 0; }.stat-strip > div:nth-child(2) { border: 0; }.section-heading { align-items: start; flex-direction: column; gap: 8px; }.section-heading h2 { font-size: 28px; }.library-layout { display: block; }.filter-rail { border: 0; border-bottom: 1px solid var(--line); padding: 0 0 18px; margin-bottom: 28px; display: grid; grid-template-columns: 1fr 1fr; gap: 0 14px; }.filter-rail .filter-label, .filter-rail .search-field, .filter-rail .quick-filter, .filter-rail .privacy-note { grid-column: 1/-1; }.quick-filter { display: grid; grid-template-columns: repeat(3,1fr); gap: 10px; }.quick-filter .filter-label { grid-column: 1/-1; }.quick-filter button { border: 1px solid var(--line); padding: 8px; }.privacy-note { margin-top: 20px; }.paper-grid { min-height: 320px; }.practice-toolbar { gap: 8px; }.session-title strong { font-size: 14px; max-width: 150px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }.session-tools { min-width: auto; }.practice-layout { display: block; }.question-map-panel { margin-bottom: 17px; }.question-map { display: flex; overflow-x: auto; max-height: none; padding: 11px 0; }.map-dot { flex: 0 0 28px; }.map-legend { display: none; }.question-card { padding: 22px 17px; min-height: 500px; }.question-stem { font-size: 18px; }.record-grid { grid-template-columns: 1fr; }.mistake-grid { grid-template-columns: 1fr; }.module-row { grid-template-columns: 115px 1fr 55px; gap: 8px; }.page-heading { margin-bottom: 25px; } }