@charset "UTF-8";
:root{color-scheme:light;--bg:#faf8f2;--surface:#fffefa;--soft:#f0f2ea;--green:#235747;--green-hover:#174435;--green-soft:#e7efe7;--text:#25352e;--muted:#66736b;--line:#e0e4da;--red:#a84435;--red-soft:#fbede7;--amber:#966a27;--shadow:0 12px 38px #283d2510;--radius:16px;--header-bg:#faf8f2f5}
:root[data-theme=dark]{color-scheme:dark;--bg:#141e19;--surface:#1c2821;--soft:#24342a;--green:#91c6a5;--green-hover:#b1dcc0;--green-soft:#294435;--text:#e4ece3;--muted:#a1b0a3;--line:#35473a;--red:#f2a290;--red-soft:#442e28;--amber:#d6b16d;--shadow:0 12px 38px #0002;--header-bg:#141e19f5}
@media(prefers-color-scheme:dark){:root:not([data-theme=light]){color-scheme:dark;--bg:#141e19;--surface:#1c2821;--soft:#24342a;--green:#91c6a5;--green-hover:#b1dcc0;--green-soft:#294435;--text:#e4ece3;--muted:#a1b0a3;--line:#35473a;--red:#f2a290;--red-soft:#442e28;--amber:#d6b16d;--shadow:0 12px 38px #0002;--header-bg:#141e19f5}}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:100px;scrollbar-gutter:stable}body{margin:0;background:var(--bg);color:var(--text);font-family:"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;font-size:15px;line-height:1.65;-webkit-font-smoothing:antialiased}a{color:var(--green);text-decoration:none}a:hover{text-decoration:underline}button,input,select{font:inherit;accent-color:var(--green)}button,a,select,input{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.5}input,select{color:var(--text);background:var(--surface);border:1px solid var(--line);border-radius:8px;min-height:44px;padding:9px 12px}:focus-visible{outline:3px solid var(--green);outline-offset:4px}h1,h2,h3,h4,p{margin-top:0}h1{font-size:30px;letter-spacing:-.7px;line-height:1.35;margin-bottom:10px}h2{font-size:21px;line-height:1.4;margin-bottom:16px}h3{font-size:17px;margin-bottom:10px}h4{font-size:15px;margin-bottom:8px}p{margin-bottom:16px}svg{display:block}img{max-width:100%}fieldset{border:0;margin:0;padding:0}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}[hidden]{display:none!important}.skip-link{position:fixed;top:-100px;left:10px;z-index:30;background:var(--surface);padding:10px}.skip-link:focus{top:5px}
.site-header{border-bottom:1px solid var(--line);background:var(--header-bg);position:sticky;top:0;z-index:20;backdrop-filter:blur(16px)}.header-inner{max-width:1360px;margin:auto;padding:0 40px;min-height:86px;display:flex;align-items:center;gap:36px}.brand{display:flex;gap:12px;align-items:center;color:var(--green);flex-shrink:0}.brand:hover{text-decoration:none}.brand>svg{width:34px;height:34px;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;fill:none}.brand strong{font-size:27px;letter-spacing:-1px;line-height:1.1}.brand strong span{display:block;font-size:10px;letter-spacing:2px;font-weight:500;margin-top:6px}.desktop-nav{display:flex;gap:26px;align-self:stretch;align-items:stretch;flex:1;justify-content:center}.desktop-nav a{color:var(--muted);display:flex;align-items:center;position:relative;white-space:nowrap;font-size:14px}.desktop-nav a.active{color:var(--green);font-weight:650}.desktop-nav a.active:after{content:'';position:absolute;bottom:0;height:3px;background:var(--green);left:0;right:0}.header-tools{display:flex;align-items:center;gap:16px}.class-control{display:flex;gap:8px;align-items:center;white-space:nowrap;font-size:12px;color:var(--muted)}.class-control select{border:0;background:var(--soft);font-size:13px;font-weight:650}.icon-button{min-width:44px;min-height:44px;display:inline-flex;align-items:center;justify-content:center;color:var(--muted);border:1px solid var(--line);border-radius:50%;background:transparent}.icon-button svg{width:20px;height:20px}#main{max-width:1280px;margin:0 auto;padding:38px 40px 72px;min-height:calc(100vh - 175px);outline:0}.page-top{display:flex;align-items:flex-end;justify-content:space-between;gap:18px;margin-bottom:27px}.eyebrow{display:block;color:var(--muted);font-size:10px;font-weight:650;letter-spacing:2px;margin-bottom:10px;text-transform:uppercase}.muted{color:var(--muted)}.small{font-size:12px}.mono{font-family:"Cascadia Mono",Consolas,monospace;font-variant-numeric:tabular-nums}.page-top p{margin:0;color:var(--muted);font-size:14px}.button{min-height:44px;display:inline-flex;justify-content:center;align-items:center;gap:12px;padding:10px 18px;border:1px solid var(--line);border-radius:9px;background:var(--surface);color:var(--text);font-size:14px;font-weight:550;text-align:center;line-height:1.5}.button:hover{text-decoration:none;background:var(--soft)}.button.primary{background:var(--green);border-color:var(--green);color:var(--bg)}.button.primary:hover{background:var(--green-hover)}.button.secondary{color:var(--green);background:var(--green-soft);border-color:transparent}.button.ghost{background:transparent;border-color:transparent;color:var(--green)}.button.danger{color:var(--red)}.button.compact{padding:7px 12px;font-size:12px}.button.full{width:100%}.button-group{display:flex;gap:10px;flex-wrap:wrap}.panel{border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);overflow:hidden}.panel-pad{padding:26px}.panel-heading{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-bottom:22px}.panel-heading h2,.panel-heading h3{margin:0}.panel-heading a{font-size:12px}
.home-top,.home-bottom{display:grid;grid-template-columns:minmax(0,1.72fr) minmax(290px,1fr);gap:22px}.home-top{margin-bottom:28px}.home-bottom{align-items:start}.resume-panel{padding:30px;display:flex;align-items:center;justify-content:space-between;gap:20px;background:var(--green-soft);border-color:transparent}.resume-panel h2{font-size:25px;margin:8px 0 12px;letter-spacing:-.3px}.resume-panel p{font-size:13px;color:var(--muted);margin-bottom:20px}.resume-tag{font-size:11px;letter-spacing:1px;color:var(--green)}.resume-art{width:140px;min-width:100px;color:var(--green);opacity:.65}.resume-art svg{width:100%;height:auto}.progress-panel{padding:27px 28px}.progress-heading{display:flex;justify-content:space-between;font-size:13px;align-items:center}.progress-number{font-family:Consolas,monospace;font-size:37px;line-height:1.3;color:var(--green);margin-top:10px}.progress-number span{font-size:18px;color:var(--muted)}.progress-track{height:5px;border-radius:10px;background:var(--line);overflow:hidden;margin:15px 0}.progress-track>span{display:block;height:100%;background:var(--green);border-radius:inherit}.stat-pair{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;font-size:12px;color:var(--muted);margin-top:20px}.stat-pair strong{display:block;font-family:Consolas,monospace;font-size:22px;color:var(--text);font-weight:500}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:10px;margin:0 0 14px}.section-heading h2{font-size:18px;margin:0}.section-heading a{font-size:12px}.chapter-row{display:grid;grid-template-columns:44px minmax(0,1fr) 100px 16px;gap:18px;padding:23px 24px;align-items:center;border-bottom:1px solid var(--line);color:var(--text)}.chapter-row:last-child{border:0}.chapter-row:hover{background:var(--soft);text-decoration:none}.chapter-no{width:42px;height:42px;display:grid;place-items:center;color:var(--green);font:17px Consolas,monospace;border:1px solid var(--line);border-radius:11px;background:var(--soft)}.chapter-row h3{font-size:16px;margin:0 0 3px}.chapter-row p{font-size:11px;color:var(--muted);margin:0}.chapter-count{font-size:11px;text-align:right;color:var(--muted)}.chapter-count .progress-track{height:3px;margin:9px 0 0}.chevron{color:var(--muted);font-size:20px}.review-summary{display:flex;align-items:center;gap:12px;margin:17px 0}.review-summary strong{font:36px Consolas,monospace;color:var(--green)}.review-summary span{font-size:12px;color:var(--muted)}.sidebar-stack{display:grid;gap:18px}.topic-preview{padding:22px 24px}.topic-preview p{font-size:12px;line-height:1.9}.topic-preview h3{font-size:16px}.text-link{font-size:13px;font-weight:600}.source-note{font-size:11px;color:var(--muted);line-height:1.8;margin-top:20px}.source-note a{color:inherit;text-decoration:underline;text-underline-offset:3px}.source-note .dot{display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--green);margin-right:6px}.quick-modes{display:flex;gap:8px;flex-wrap:wrap;margin-top:18px}.site-footer{max-width:1200px;margin:0 auto;padding:20px 0 26px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:15px;font-size:11px;color:var(--muted)}.site-footer a{color:var(--muted)}.footer-separator{margin:0 9px;color:var(--line)}.mobile-nav{display:none}.notice,.exam-banner{max-width:1200px;margin:16px auto 0;padding:12px 18px;border-radius:9px;background:var(--green-soft);font-size:13px;display:flex;justify-content:space-between;align-items:center;gap:15px}
.breadcrumb{display:flex;flex-wrap:wrap;gap:9px;align-items:center;color:var(--muted);font-size:12px;margin-bottom:20px}.breadcrumb a{min-height:32px;display:inline-flex;align-items:center}/* 题型徽标：比 .tag 更醒目，单选绿 / 多选琥珀 */
.qtype-row{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:0 0 14px}.qtype{display:inline-flex;align-items:center;gap:6px;padding:5px 13px;border-radius:999px;font-size:13px;font-weight:700;letter-spacing:.5px}.qtype.single{background:var(--green-soft);color:var(--green)}.qtype.multi{background:var(--amber);color:#fff}.qtype-rule{font-size:12px;color:var(--muted)}.qtype.multi+.qtype-rule{color:var(--amber)}.multi-hint{margin:0 0 14px;padding:9px 14px;border-radius:9px;background:var(--amber);color:#fff;font-size:12.5px;font-weight:600}.tag{display:inline-flex;align-items:center;font-size:10px;letter-spacing:.4px;border:1px solid var(--line);border-radius:5px;padding:3px 8px;color:var(--muted)}.tag.green{color:var(--green);background:var(--green-soft);border-color:transparent}.tag.amber{color:var(--amber)}.tag.red{color:var(--red)}.quiz-layout{display:grid;grid-template-columns:minmax(0,2fr) minmax(250px,.85fr);gap:26px;align-items:start}.question-panel{padding:30px}.question-meta{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:20px}.question-meta-left{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.question-meta .mono{font-size:12px;color:var(--muted)}.question-text{font-size:21px;line-height:1.8;font-weight:550;margin-bottom:26px;overflow-wrap:anywhere}.question-figure{margin:0 0 24px;text-align:center}.question-figure button{background:#fff;border:1px solid var(--line);border-radius:10px;padding:12px;max-width:100%}.question-figure img{max-height:320px;object-fit:contain}.question-figure figcaption{font-size:11px;color:var(--muted);margin-top:7px}.options{display:grid;gap:12px;border:0}.option{display:flex;align-items:flex-start;gap:14px;width:100%;min-height:62px;padding:16px 18px;text-align:left;background:var(--surface);border:1px solid var(--line);border-radius:11px;color:var(--text);font-size:16px;line-height:1.7}.option:hover:not(:disabled){border-color:var(--green);background:var(--soft)}.option:disabled{opacity:1;cursor:default}/* 单选=圆（单选钮），多选=方（复选框）：形态本身就是题型提示 */
.option-key{position:relative;width:34px;height:34px;flex-shrink:0;display:grid;place-items:center;border:1.5px solid var(--line);border-radius:50%;font:600 14px Consolas,monospace;background:var(--surface)}.option.multi .option-key{border-radius:9px}.option.multi.selected .option-key::after{content:"✓";position:absolute;top:-7px;right:-7px;width:18px;height:18px;border-radius:50%;background:var(--green);color:var(--bg);font-size:11px;line-height:1;display:grid;place-items:center;border:2px solid var(--surface)}.option.selected{border-color:var(--green);background:var(--green-soft)}.option.selected .option-key{background:var(--green);color:var(--bg);border-color:var(--green)}.option.correct{border-color:var(--green);background:var(--green-soft)}.option.incorrect{border-color:var(--red);background:var(--red-soft)}.option-content{flex:1;overflow-wrap:anywhere;min-width:0}.option-state{font-size:11px;white-space:nowrap;color:var(--green);align-self:center}.option.incorrect .option-state{color:var(--red)}.feedback{display:flex;align-items:flex-start;gap:12px;padding:16px 18px;border-radius:10px;background:var(--green-soft);color:var(--green);margin-top:24px;font-size:14px}.feedback.wrong{background:var(--red-soft);color:var(--red)}.feedback strong{display:block}.feedback p{font-size:12px;margin:6px 0 0}.explanation{margin-top:22px;border-top:1px solid var(--line);padding-top:18px}.explanation summary,.related-block summary{cursor:pointer;min-height:44px;display:flex;align-items:center;justify-content:space-between;font-weight:600;list-style:none}.explanation summary::after,.related-block summary::after{content:'＋';color:var(--muted)}.explanation[open] summary::after,.related-block[open] summary::after{content:'−'}.explanation-body{font-size:14px;line-height:1.9;padding-top:12px;white-space:pre-line;overflow-wrap:anywhere}.knowledge-aside{padding:24px}.knowledge-aside p{font-size:13px;line-height:1.9}.knowledge-aside img{background:#fff;border-radius:8px}.question-tools{display:flex;gap:10px;justify-content:space-between;margin:18px 0 0}/* 与 .site-header 同款处理，形成上下呼应的两条栏。
   内层栅格必须与 .quiz-layout 保持一致，按钮列才会与题面列对齐。 */
/* 卡片页脚：PC 上与题干/选项同属一张完整卡片 */
.quiz-actions{margin-top:22px;padding-top:16px;border-top:1px solid var(--line)}
.quiz-actions-col{display:flex;align-items:center;justify-content:space-between;gap:12px}/* 主按钮宽度下限见 .quiz-actions .button.primary */.quiz-actions .button.primary{min-width:158px}.action-hint{font-size:11px;color:var(--muted)}.session-progress{font:14px Consolas,monospace;color:var(--green)}.related-block{border-top:1px solid var(--line);margin-top:18px;padding-top:10px}.related-block a{display:block;font-size:13px;padding:8px 0}
.toolbar{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-bottom:24px}.search{flex:1;min-width:180px;max-width:560px}.search input{width:100%;padding:12px 16px;min-height:48px}.filter-button{padding:8px 13px;border-radius:8px;min-height:44px;background:transparent;border:1px solid var(--line);color:var(--muted);font-size:13px}.filter-button.active{background:var(--green);color:var(--bg);border-color:var(--green)}.knowledge-layout{display:grid;grid-template-columns:205px minmax(0,1fr);gap:32px}.knowledge-sidebar{position:sticky;top:110px;align-self:start;display:grid;gap:6px}.knowledge-sidebar a{padding:12px 14px;border-radius:8px;font-size:13px;color:var(--muted)}.knowledge-sidebar a.active{background:var(--green-soft);color:var(--green);font-weight:600}.topic-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px;margin-bottom:30px}.topic-card{display:flex;flex-direction:column;padding:22px;color:var(--text);border:1px solid var(--line);border-radius:12px;background:var(--surface)}.topic-card:hover{text-decoration:none;border-color:var(--green)}.topic-card .eyebrow{font-size:9px;margin:0 0 12px}.topic-card h3{font-size:16px}.topic-card p{font-size:12px;color:var(--muted);margin-bottom:15px;line-height:1.8;flex:1}.topic-card-footer{display:flex;justify-content:space-between;gap:8px;font-size:11px;color:var(--green)}.section-title{font-size:16px;margin:24px 0 14px}.article{max-width:820px;padding:34px}.article h1{font-size:29px}.article h2{font-size:19px;margin-top:30px;border-top:1px solid var(--line);padding-top:24px}.article p,.article li{font-size:15px;line-height:1.95;overflow-wrap:anywhere}.article .lead{font-size:17px;color:var(--green);line-height:1.85;margin:22px 0}.article ul{padding-left:22px}.article li{margin-bottom:14px}.article .point-link{font-size:11px;display:inline-flex;margin:6px 10px 0 0}.article figure{padding:18px;background:#fff;border-radius:12px;margin:24px 0}.article figure img{max-height:360px;display:block;margin:auto}.article figcaption{font-size:11px;text-align:center;color:#657568}.formula{padding:18px 22px;background:var(--soft);border-radius:10px;margin-bottom:12px}.formula code{font-size:18px;color:var(--green);white-space:pre-wrap;overflow-wrap:anywhere}.formula p{font-size:12px;margin:8px 0 0}.article-sources{font-size:12px;color:var(--muted);border-top:1px solid var(--line);margin-top:25px;padding-top:18px}.article-sources p{font-size:12px;margin:6px 0}.list-row{padding:20px 22px;border-bottom:1px solid var(--line);display:flex;gap:20px;align-items:center;justify-content:space-between}.list-row:last-child{border-bottom:0}.list-row h3{font-size:15px;margin:0 0 5px}.list-row p{font-size:12px;color:var(--muted);margin:0}.list-row .button{flex-shrink:0}.review-tabs{display:flex;gap:10px;margin-bottom:22px;flex-wrap:wrap}.review-stat{font-family:Consolas,monospace;margin-left:7px}.empty-state{padding:64px 24px;text-align:center}.empty-state h2{font-size:22px}.empty-state p{color:var(--muted);font-size:14px;max-width:420px;margin:10px auto 24px}.empty-symbol{font-size:35px;color:var(--green);margin-bottom:15px}.exam-intro{max-width:800px;margin:0 auto}.exam-rule-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:28px 0}.exam-rule-grid div{padding:20px 8px;text-align:center;border:1px solid var(--line);border-radius:10px;background:var(--soft)}.exam-rule-grid strong{display:block;font:28px Consolas,monospace;color:var(--green)}.exam-rule-grid span{font-size:12px;color:var(--muted)}.exam-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:7px;margin-top:18px}.exam-cell{min-height:44px;border:1px solid var(--line);border-radius:6px;background:var(--surface);color:var(--muted);font:12px Consolas,monospace}.exam-cell.done{background:var(--green-soft);color:var(--green)}.exam-cell.current{border:2px solid var(--green);color:var(--green);font-weight:bold}.exam-cell.wrong{background:var(--red-soft);color:var(--red)}.timer{font:30px Consolas,monospace;color:var(--green);margin:12px 0}.timer.urgent{color:var(--red)}.result-score{font:64px Consolas,monospace;color:var(--green);line-height:1.2;margin:24px 0}.result-score span{font-size:24px;color:var(--muted)}.result-summary{display:flex;align-items:center;justify-content:space-between;gap:24px}.settings-layout{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}.settings-row{border-top:1px solid var(--line);padding:16px 0;display:flex;align-items:center;justify-content:space-between;gap:20px}.settings-row:first-of-type{border-top:0}.settings-row p{font-size:12px;color:var(--muted);margin:3px 0 0}.settings-row label{font-size:14px}.settings-row input[type=checkbox]{width:20px;height:20px;min-height:20px;flex-shrink:0}.settings-row input[type=number]{width:95px}.sync-input{width:100%;font-family:Consolas,monospace;letter-spacing:1px;margin:8px 0 15px}.history-score{font:23px Consolas,monospace;color:var(--green);white-space:nowrap}.loading-state{padding:80px 0}.loading-state p{color:var(--muted)}.error-state{padding:50px 20px;max-width:650px;margin:auto}.error-state pre{white-space:pre-wrap;font-size:12px;overflow-wrap:anywhere}.toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%);max-width:min(90vw,580px);padding:14px 22px;background:var(--text);color:var(--bg);font-size:13px;border-radius:12px;z-index:60;box-shadow:var(--shadow)}dialog{border:1px solid var(--line);border-radius:20px;background:var(--surface);color:var(--text);padding:35px;width:min(540px,calc(100vw - 32px));box-shadow:var(--shadow)}dialog::backdrop{background:#16261ccc;backdrop-filter:blur(4px)}dialog h2{font-size:25px}.class-options{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:25px 0}.class-options label{padding:16px 12px;border:1px solid var(--line);border-radius:10px;cursor:pointer}.class-options label:has(input:checked){background:var(--green-soft);border-color:var(--green)}.class-options strong{display:block;font-size:20px;margin:5px 0}.class-options span{display:block;font-size:10px;color:var(--muted)}.class-options input{min-height:0;margin:0}.image-dialog{width:min(1000px,96vw)}.image-dialog img{display:block;margin:15px auto 0;max-height:75vh;object-fit:contain;background:white}.image-dialog>.button{margin-left:auto;display:flex}.chapter-groups{display:grid;gap:22px}.chapter-group .panel-heading{margin:0;padding:22px;border-bottom:1px solid var(--line)}.subchapter{display:flex;justify-content:space-between;align-items:center;gap:15px;padding:16px 22px;border-bottom:1px solid var(--line)}.subchapter:last-child{border:0}.subchapter>a:first-child{color:var(--text);font-size:14px}.subchapter .small{color:var(--muted)}
@media(min-width:1100px){.knowledge-aside{position:sticky;top:110px}.home-top .resume-panel{min-height:250px}}
@media(max-width:1150px){.header-inner{padding:0 25px;gap:22px}.desktop-nav{gap:18px}.brand strong span{letter-spacing:1px}.class-control>span{display:none}.header-tools{gap:10px}.site-footer{margin:0 30px}.notice,.exam-banner{margin-left:30px;margin-right:30px}.resume-art{width:100px}.quiz-layout{grid-template-columns:minmax(0,1.9fr) minmax(220px,1fr)}}
@media(max-width:900px){body{padding-bottom:96px}.quiz-actions{position:fixed;z-index:30;left:0;right:0;bottom:0;margin:0;padding:12px 25px calc(12px + env(safe-area-inset-bottom));background:var(--header-bg);backdrop-filter:blur(16px);border-top:1px solid var(--line)}.quiz-actions-col{gap:12px}
.desktop-nav{gap:14px}.desktop-nav a{font-size:12px}.header-inner{gap:16px;padding:0 20px}.brand>svg{width:26px}.brand strong{font-size:23px}.brand strong span{font-size:8px}.header-tools{gap:6px}.home-top,.home-bottom{grid-template-columns:minmax(0,1.55fr) minmax(240px,1fr);gap:17px}#main{padding:30px 25px 30px}.resume-panel{padding:23px}.resume-art{display:none}.resume-panel h2{font-size:23px}.progress-panel{padding:23px}.chapter-row{grid-template-columns:36px minmax(0,1fr) 72px 12px;gap:12px;padding:21px 18px}.chapter-no{width:35px;height:35px}.chapter-row h3{font-size:14px}.question-panel{padding:24px}.question-text{font-size:19px}.quiz-layout{display:block}.knowledge-aside{margin-top:20px}.knowledge-layout{grid-template-columns:165px minmax(0,1fr);gap:22px}.topic-grid{grid-template-columns:1fr}.settings-layout{gap:18px}.article{padding:26px}.article h1{font-size:25px}}
@media(max-width:680px){body{font-size:14px;padding-bottom:88px}.header-inner{min-height:72px;padding:0 20px;justify-content:space-between;gap:10px}.brand{gap:9px}.brand>svg{width:28px}.brand strong{font-size:24px}.brand strong span{font-size:8px;letter-spacing:1.5px}.desktop-nav{display:none}.header-tools{gap:10px}.class-control select{font-size:12px;padding:8px}#main{padding:27px 20px 30px;min-height:calc(100vh - 180px)}h1{font-size:26px;letter-spacing:-.5px}.page-top{align-items:flex-start;margin-bottom:23px}.page-top p{font-size:12px}.page-top .button{padding:8px 12px;font-size:12px}.eyebrow{font-size:9px;letter-spacing:1.5px;margin-bottom:9px}.home-top{display:block;margin-bottom:26px}.resume-panel{padding:25px;margin-bottom:16px}.resume-panel h2{font-size:23px}.resume-panel p{font-size:12px}.resume-art{display:block;width:90px;min-width:70px}.resume-panel .button{font-size:13px;padding:10px 16px}.progress-panel{padding:20px 22px;display:grid;grid-template-columns:1fr 1fr;gap:0 20px}.progress-heading{grid-column:1/-1;font-size:12px}.progress-number{font-size:31px;margin-top:10px;align-self:end}.progress-number span{font-size:15px}.progress-panel>.progress-track{grid-column:1;grid-row:3;margin:10px 0 4px}.stat-pair{grid-column:2;grid-row:2/4;margin:12px 0 0;gap:12px;border-left:1px solid var(--line);padding-left:20px;font-size:10px}.stat-pair strong{font-size:20px}.home-bottom{display:block}.sidebar-stack{margin-top:25px;gap:16px}.chapter-row{padding:19px 17px;grid-template-columns:35px minmax(0,1fr) 66px 10px;gap:11px}.chapter-row h3{font-size:14px}.chapter-row p{font-size:10px;line-height:1.6;margin-top:4px}.chapter-count{font-size:10px}.quick-modes .button{flex:1;font-size:12px;padding:10px 12px}.section-heading h2{font-size:17px}.panel-pad{padding:22px}.site-footer{margin:0 20px;padding:18px 0 20px;font-size:10px;display:flex;flex-wrap:wrap;gap:10px}.site-footer>span:first-child{flex:1}.site-footer #offline-status{width:100%}.mobile-nav{display:grid;grid-template-columns:repeat(5,1fr);position:fixed;bottom:0;left:0;right:0;z-index:25;background:var(--header-bg);border-top:1px solid var(--line);padding:8px 12px calc(8px + env(safe-area-inset-bottom));backdrop-filter:blur(14px)}.mobile-nav a{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:1px;color:var(--muted);font-size:10px;min-height:45px}.mobile-nav a>span{font-size:23px;line-height:1.2}.mobile-nav a.active{color:var(--green);font-weight:650}.mobile-nav a.active>span{background:var(--green-soft);border-radius:8px;width:44px;text-align:center}.notice,.exam-banner{margin:12px 20px 0;font-size:11px;padding:10px 14px}.breadcrumb{font-size:11px;gap:7px;margin-bottom:13px}.question-panel{padding:0;background:transparent;border:0;border-radius:0}.question-meta{margin-bottom:19px}.question-meta-left{gap:8px}.question-meta .mono{font-size:10px}.tag{font-size:9px}.question-text{font-size:19px;line-height:1.85;margin-bottom:24px}.option{font-size:15px;padding:15px 14px;gap:12px;min-height:62px}.option-key{width:27px;height:27px;font-size:13px}.option-state{font-size:10px}.options{gap:11px}.question-figure img{max-height:260px}.feedback{padding:15px;font-size:13px}.feedback p{font-size:11px}.explanation-body{font-size:14px;line-height:1.95}.knowledge-aside{padding:21px;margin-top:24px;background:var(--surface)}.quiz-actions{padding:12px 20px calc(12px + env(safe-area-inset-bottom))}.quiz-actions-col{gap:10px}.quiz-actions .button{font-size:13px;padding:10px 13px}.quiz-actions .button.primary{min-width:120px;flex:1;max-width:240px}.quiz-actions .action-hint{display:none}body.focus-mode .mobile-nav{display:none}.question-tools{margin-top:18px}.session-progress{font-size:12px}.knowledge-layout{display:block}.knowledge-sidebar{position:static;display:flex;overflow-x:auto;gap:6px;margin-bottom:20px;padding-bottom:8px}.knowledge-sidebar a{white-space:nowrap;padding:9px 12px;font-size:12px;border:1px solid var(--line)}.topic-grid{grid-template-columns:1fr;gap:12px}.topic-card{padding:20px}.toolbar{gap:8px;margin-bottom:20px}.search{max-width:none;flex-basis:100%}.filter-button{font-size:12px;padding:8px 10px}.article{padding:23px 20px}.article h1{font-size:24px}.article .lead{font-size:16px}.article p,.article li{font-size:14px}.article h2{font-size:18px}.article ul{padding-left:18px}.article figure{padding:10px}.article-sources{overflow-wrap:anywhere}.list-row{padding:18px;gap:12px}.list-row h3{font-size:14px}.list-row .button{padding:8px 10px;font-size:12px}.list-row p{font-size:10px}.review-tabs{gap:7px}.review-tabs .button{font-size:12px;padding:9px 12px}.exam-rule-grid{grid-template-columns:repeat(2,1fr);gap:10px}.exam-rule-grid div{padding:18px 10px}.exam-rule-grid strong{font-size:27px}.exam-grid{grid-template-columns:repeat(6,1fr);gap:6px}.result-summary{display:block}.result-score{font-size:52px}.settings-layout{display:block}.settings-layout>.panel{margin-bottom:20px}.settings-row{gap:14px}.settings-row p{font-size:11px}.settings-row label{font-size:13px}.history-score{font-size:20px}.empty-state{padding:45px 20px}.toast{bottom:96px;font-size:12px}.class-options{gap:8px}.class-options label{padding:13px 8px}.class-options span{font-size:9px}dialog{padding:25px}dialog h2{font-size:23px}.subchapter{padding:15px;gap:10px;align-items:flex-start}.subchapter>a:first-child{font-size:13px}.subchapter .button{font-size:11px;padding:8px 10px}.subchapter .small{font-size:10px}.chapter-group .panel-heading{padding:20px 16px}.chapter-group h2{font-size:17px}}
@media(max-width:380px){#main{padding-left:16px;padding-right:16px}.header-inner{padding:0 16px}.resume-art{display:none}.chapter-row{grid-template-columns:30px minmax(0,1fr) 58px 8px;gap:9px;padding:18px 13px}.chapter-no{width:30px;height:34px;font-size:14px}.chapter-row h3{font-size:13px}.option{gap:10px;padding:14px 12px}.option-state{font-size:9px}.question-text{font-size:18px}.stat-pair{gap:8px;padding-left:12px}.progress-panel{gap:0 12px;padding:18px}.brand strong span{letter-spacing:.6px}.header-tools{gap:7px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}
/* Keep meaningful Chinese phrases together on narrow screens. */
@media(max-width:680px){.page-top{display:block}.page-top>.button{margin-top:12px;white-space:nowrap}.resume-art{display:none}.progress-panel{grid-template-columns:.8fr 1.2fr;gap:0 14px}.stat-pair{padding-left:14px;gap:10px}.article li h3{font-size:14px;font-weight:600;line-height:1.8}.knowledge-aside .button{white-space:normal}}

/* --- 追加：考试吸顶倒计时、练习进度条、连续学习、复盘筛选、确认对话框、打印 --- */
.session-track{margin:0 0 18px}.session-track .progress-track{height:3px;margin:0;border-radius:6px}
.stat-pair>div.streak-hot strong{color:var(--green)}.stat-pair>div.streak-hot strong::after{content:'CF';font-size:8px;vertical-align:super;margin-left:5px;color:var(--green)}
.exam-bar{position:sticky;top:86px;z-index:15;display:flex;align-items:center;justify-content:space-between;gap:14px;padding:10px 18px;margin:0 0 20px;border:1px solid var(--line);border-radius:12px;background:var(--header-bg);backdrop-filter:blur(14px);box-shadow:var(--shadow)}
.exam-bar .exam-pos{font:600 13px Consolas,monospace;color:var(--green);white-space:nowrap}
.exam-bar .timer{font-size:23px;margin:0;line-height:1.2;flex:1;text-align:center}
.exam-bar .small{white-space:nowrap}
.answer-card>summary{cursor:pointer;list-style:none;display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:44px;font-weight:600;font-size:14px}
.answer-card>summary::-webkit-details-marker{display:none}
.answer-card>summary::after{content:'˜4';color:var(--muted);font-size:18px}
.answer-card[open]>summary::after{content:'˜3'}
.answer-card>p{margin:6px 0 12px}
.unanswered-chips{display:flex;flex-wrap:wrap;gap:6px;margin:12px 0 18px}
.auto-next{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:12px;padding:8px 14px;border:1px solid var(--line);border-radius:10px;background:var(--soft);font-size:12px;color:var(--muted)}
.auto-next .button{min-height:36px;padding:6px 12px;font-size:12px}
.confirm-actions{margin-top:26px;justify-content:flex-end}
.filter-button{cursor:pointer}
#result-list>details[hidden]{display:none}
@media(max-width:900px){.exam-bar{top:80px}}
@media(max-width:680px){
  .exam-bar{top:72px;gap:10px;padding:8px 12px;margin-bottom:16px;border-radius:10px}
  .exam-bar .exam-pos{font-size:12px}
  .exam-bar .timer{font-size:20px}
  .exam-bar .small{font-size:10px}
  .exam-bar .button{padding:8px 12px;font-size:12px;min-height:40px}
  .stat-pair{grid-template-columns:1fr;gap:8px}
  .stat-pair>div:last-child{grid-column:auto}
  .session-track{margin-bottom:14px}
}
@media print{
  .site-header,.mobile-nav,.site-footer,.quiz-actions,.exam-bar,.toast,#notice,#exam-banner,.skip-link,.breadcrumb,.review-tabs,.toolbar,.knowledge-sidebar,.button,dialog{display:none!important}
  html,body{background:#fff;color:#000}
  #main{padding:0;max-width:none;min-height:0}
  .panel{border:1px solid #ccc;box-shadow:none;break-inside:avoid}
  .article{max-width:none;padding:0}
  .quiz-layout,.knowledge-layout,.home-top,.home-bottom,.settings-layout{display:block}
  .knowledge-aside{margin-top:18px}
  .result-score,.progress-number,.history-score{color:#000}
  .question-text{font-size:16pt}
}

/* --- 本题详情翻牌（右侧卡片） --- */
/* 翻牌：单面板。
   不用双面绝对定位 + backface-visibility——实测它会把已朝前的面也剔除，且需 JS 同步高度、
   内容超出会被 .panel 的 overflow:hidden 裁掉。
   这里只渲染当前可见的那一面（自然撑高），动画为：转到 90° → 换内容 → 从 -90° 转回。 */
.flip-card{position:relative}
.flip-inner{transform-origin:center center;transition:transform .28s cubic-bezier(.4,.05,.2,1)}
.flip-face[hidden]{display:none}
.flip-wait{display:inline-block;margin-top:8px;font-size:11px;letter-spacing:1px;color:var(--muted);border:1px dashed var(--line);border-radius:8px;padding:6px 11px}
.flip-back .source-note{margin-top:16px}
/* 答案解析现在在右卡 */
.answer-text{margin:10px 0 12px;padding:12px 14px;border-radius:10px;background:var(--green-soft);font-size:13.5px;line-height:1.9}
.answer-text p{margin:0 0 8px}.answer-text p:last-child{margin:0}
@media(prefers-reduced-motion:reduce){.flip-inner{transition:none}}