/* 单一浅色界面；布局与交互样式集中维护，无图标模块或多语言依赖。 */
:root{--paper:#f7f8fa;--white:#fff;--ink:#1d2839;--muted:#687486;--line:#e3e7ed;--blue:#315be8;--blue-soft:#eef2ff;--hover:#f0f3f8;--green:#217858;--amber:#916319;--red:#a6533d}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:14px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}button,input,select,textarea{font:inherit}button,a,input,select,textarea,summary{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}a{color:var(--blue);text-underline-offset:3px}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:2px solid var(--blue);outline-offset:3px}button{border:0}.topbar{height:72px;display:flex;align-items:center;gap:32px;padding:0 36px;border-bottom:1px solid var(--line);background:var(--white)}.brand{font-size:20px;font-weight:750;text-decoration:none;color:var(--ink);letter-spacing:-.6px}.topnote{font-size:10px;letter-spacing:1.8px;color:var(--muted)}.topbar>button{margin-left:auto}.text-button{color:var(--muted);background:transparent;padding:8px 10px;border-radius:6px}.text-button:hover{color:var(--blue);background:var(--blue-soft)}.workspace{display:grid;grid-template-columns:254px minmax(0,1fr);max-width:1600px;margin:auto}.sidebar{padding:36px 20px;align-self:start;position:sticky;top:0;max-height:100vh;overflow:auto}.side-heading{color:var(--muted);font-size:12px;letter-spacing:1px;display:flex;justify-content:space-between;margin:0 12px 20px}.side-heading span{font-variant-numeric:tabular-nums}nav{display:grid;gap:6px}.category{background:transparent;border:1px solid transparent;border-radius:7px;padding:12px;display:flex;align-items:center;justify-content:space-between;text-align:left;color:var(--muted);width:100%}.category:hover{background:#e9edf5}.category[aria-pressed="true"]{color:var(--blue);background:#e3eaff;border-color:#c4d1ff;font-weight:650}.category small{font-size:11px;font-weight:400}.side-note{border-top:1px solid var(--line);margin:32px 12px 0;padding-top:24px}.side-note strong{font-size:13px}.side-note p{font-size:12px;color:var(--muted);line-height:1.9}.progress{margin:25px 12px 14px;font-size:12px}.progress>div{display:flex;justify-content:space-between}.progress progress{width:100%;height:5px;accent-color:var(--blue);border:0;margin:12px 0 6px}.progress small{font-size:10px;color:var(--muted)}.import-label{display:block;font-size:12px;color:var(--muted);margin:8px 10px;cursor:pointer}.import-label input{display:block;font-size:11px;max-width:190px;margin-top:8px}main{min-width:0;border-left:1px solid var(--line);padding:43px 48px 24px}.eyebrow{color:var(--blue);font-size:11px;letter-spacing:1.8px;font-weight:650}h1{font-size:34px;line-height:1.35;letter-spacing:-1px;margin:14px 0}h2{font-size:18px;margin:0}p{margin:8px 0}.hero>p{color:var(--muted);font-size:14px}.stats{display:flex;align-items:center;gap:29px;margin:27px 0 32px;color:var(--muted);font-size:12px}.stats b{font-size:22px;color:var(--ink);font-weight:650;margin-right:5px}.stats .updated{margin-left:auto;font-size:10px}.controls{padding:20px;background:var(--white);border:1px solid var(--line);border-radius:10px}.search-label>span{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}#search{width:100%;border:1px solid var(--line);border-radius:6px;background:var(--paper);padding:11px 14px;color:var(--ink)}.filters{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-top:14px}.filters label{font-size:11px;color:var(--muted);display:flex;align-items:center;gap:6px}.filters select{border:1px solid var(--line);background:var(--white);color:var(--ink);padding:7px 22px 7px 8px;border-radius:5px;font-size:12px;max-width:180px}.secondary{color:var(--blue);background:var(--blue-soft);border:1px solid #d9e2ff;padding:7px 12px;border-radius:6px;font-size:12px}.secondary:hover{background:#dfe7ff}.filters .text-button{font-size:11px}.list-heading{display:flex;align-items:center;justify-content:space-between;margin:30px 0 15px}.list-heading p{font-size:11px;color:var(--muted);margin:4px 0 0}.list-heading button{font-size:12px}.group-title{font-size:12px;color:var(--muted);margin:23px 0 10px;font-weight:500}.question{border:1px solid var(--line);border-radius:9px;background:var(--white);margin-bottom:12px;overflow:hidden;scroll-margin-top:24px}.question-header{display:flex;align-items:flex-start;gap:16px;padding:22px 23px 12px}.number{color:#8e9aad;font:12px/1.9 ui-monospace,monospace;padding-top:1px}.question-main{min-width:0;flex:1}.question h3{font-size:16px;font-weight:650;margin:0 0 10px;line-height:1.6}.tags{display:flex;gap:7px;flex-wrap:wrap;align-items:center}.tag{font-size:10px;border-radius:4px;background:#f2f4f7;color:var(--muted);padding:2px 7px}.difficulty-1{background:#eaf5ef;color:var(--green)}.difficulty-2{background:#fff5de;color:var(--amber)}.difficulty-3{background:#faeee8;color:var(--red)}.question-body{padding:0 23px 20px 57px}.draft{margin:9px 0 12px}.draft summary{color:var(--muted);font-size:12px;cursor:pointer;list-style-position:inside}.draft textarea{width:100%;min-height:112px;resize:vertical;margin-top:10px;padding:12px;border:1px solid var(--line);border-radius:6px;background:var(--paper);color:var(--ink);font-size:13px}.draft small{font-size:10px;color:var(--muted)}.question-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.reveal{background:var(--blue);color:white;padding:8px 14px;border-radius:6px;font-size:12px}.reveal:hover{background:#2449c9}.self-rating{margin-left:auto;display:flex;gap:6px}.rating{background:var(--white);border:1px solid var(--line);color:var(--muted);padding:6px 10px;border-radius:5px;font-size:11px}.rating:hover{background:var(--hover)}.rating[aria-pressed="true"]{background:var(--blue-soft);color:var(--blue);border-color:var(--blue)}.answer{margin:18px 0 0;border-top:1px solid var(--line);padding-top:18px}.answer[hidden]{display:none}.answer-label{font-size:10px;color:var(--blue);letter-spacing:1px;font-weight:650}.answer-core{font-size:14px;line-height:1.9;margin:8px 0 15px}.answer h4{font-size:12px;margin:16px 0 5px}.answer ol{padding-left:20px;margin:7px 0;color:#46546a;font-size:13px}.answer li{padding:3px 0}.pitfall{background:#faf6ef;border-left:3px solid #d3b37c;padding:10px 12px;font-size:12px;color:#78603b;margin:15px 0}.followup{font-size:13px;color:#46546a}.references{font-size:11px;color:var(--muted);border-top:1px dashed var(--line);margin-top:17px;padding-top:12px}.references a{display:inline-block;margin:4px 10px 4px 0}.empty{text-align:center;padding:70px 20px;color:var(--muted);border:1px dashed var(--line);border-radius:8px}footer{color:var(--muted);font-size:10px;line-height:1.9;margin:32px 0 10px}dialog{border:1px solid var(--line);border-radius:12px;width:min(790px,92vw);max-height:85vh;padding:28px;color:var(--ink);box-shadow:0 20px 100px #15233a26}dialog::backdrop{background:#15233a66}.dialog-heading{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:20px}#source-content{font-size:13px;line-height:1.85}#source-content h3{font-size:14px;margin-top:24px}#source-content .source{border-top:1px solid var(--line);padding:14px 0}#source-content small{color:var(--muted)}#notice{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);max-width:90vw;background:var(--ink);color:white;border-radius:7px;font-size:13px;padding:10px 18px;display:none;z-index:5}
@media(min-width:1500px){main{padding-right:80px;padding-left:64px}}@media(max-width:1100px){main{padding:32px 26px}.workspace{grid-template-columns:220px minmax(0,1fr)}.stats{gap:16px}.updated{display:none}.topnote{display:none}}@media(max-width:740px){.topbar{height:60px;padding:0 18px;gap:8px}.brand{font-size:18px}.topbar>button{font-size:11px}.workspace{display:block}.sidebar{position:static;max-height:none;padding:20px 18px 0}.side-heading,.side-note,.progress,.sidebar>#export,.import-label{display:none}nav{display:flex;overflow-x:auto;padding-bottom:9px;gap:7px}.category{width:auto;white-space:nowrap;padding:8px 12px;background:var(--white);border-color:var(--line);gap:10px}.category small{display:none}main{border:0;padding:23px 18px}h1{font-size:27px}.hero>p{font-size:12px}.stats{gap:17px;margin:20px 0}.stats b{font-size:19px}.stats span{font-size:10px}.controls{padding:13px}.filters{gap:8px}.filters label{flex:1;min-width:110px;justify-content:space-between}.filters select{max-width:150px;width:100%}.question-header{padding:18px 16px 10px;gap:10px}.question h3{font-size:15px}.question-body{padding:0 16px 18px}.self-rating{margin-left:auto}.rating{padding:6px 8px}.list-heading{margin-top:25px}.group-title{font-size:11px}.eyebrow{font-size:9px}.number{font-size:10px}dialog{padding:20px}.answer-core{font-size:13px}}

.filters label{white-space:nowrap}.record-options{margin-top:12px;font-size:11px;color:var(--muted)}.record-options summary{cursor:pointer}.record-tools{display:flex;flex-wrap:wrap;align-items:center;gap:12px;padding-top:8px}.record-tools .import-label{display:flex;align-items:center;gap:10px;margin:0}.record-tools input{margin:0}.record-tools .text-button{font-size:12px}

/* 原帖依据、补充练习与答案分层分开呈现，避免把整理内容误认作原题。 */
.question-origin{border-left:2px solid var(--line);padding:0 12px;margin:4px 0 17px;font-size:12px;color:var(--muted)}
.origin-label{font-size:10px;font-weight:650;letter-spacing:.3px}.origin-label a{font-weight:400}
.question-origin p{color:var(--ink);margin:5px 0;line-height:1.8}.question-origin small{font-size:10px;line-height:1.8;display:block}
.practice-drill{margin:12px 0 18px;border:1px solid var(--line);border-radius:7px;background:var(--paper);padding:12px 14px}
.practice-drill>summary{cursor:pointer;font-size:12px;color:var(--ink);font-weight:600;line-height:1.9}
.practice-drill>summary>span{font-size:10px;font-weight:400;color:var(--muted);margin-left:8px}
.practice-drill>h4{font-size:11px;color:var(--blue);margin:16px 0 6px}
.practice-drill>p{font-size:13px;line-height:1.9;margin:6px 0 15px}
.practice-drill>ol{padding-left:19px;margin:8px 0 4px;font-size:12px}
.practice-drill li{padding:5px 0}.practice-drill li>strong{display:block;font-size:10px;color:var(--muted)}
.practice-drill li>span{display:block;line-height:1.9}.answer-tier{margin:18px 0}
.answer-tier>h4{color:var(--blue);font-size:12px}.answer-tier>p{font-size:13px;line-height:2;color:var(--ink)}
.self-check{background:var(--blue-soft);padding:12px 14px;border-radius:6px;margin:20px 0}
.self-check>h4{margin:0 0 6px}.self-check>ul{font-size:12px;padding-left:18px;margin:0;line-height:1.9}

/* 难度按练习项标注；重点按钮与已掌握独立，选中态用实线边框区分。 */
.practice-match{font-size:11px;color:var(--muted);line-height:1.8;margin:12px 0}
.practice-heading{display:flex;align-items:center;gap:9px;margin:0 0 14px;font-size:11px;color:var(--muted)}
.practice-meta{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:7px}
.practice-meta>h4,.practice-meta>strong{margin:0;font-size:11px;color:var(--muted)}
.focus-mark{background:var(--white);color:var(--muted);border:1px solid var(--line);border-radius:5px;padding:5px 9px;font-size:11px;line-height:1.6}
.focus-mark:hover{background:var(--hover)}
.focus-mark[aria-pressed="true"]{background:var(--blue-soft);border-color:var(--blue);color:var(--blue);box-shadow:inset 0 0 0 1px var(--blue)}
.practice-meta>.focus-mark{margin-left:auto}
.practice-section{padding:12px 10px;border:1px solid transparent;border-radius:6px;margin:12px 0}
.practice-section>p{font-size:13px;line-height:1.9;margin:7px 0 0}
.practice-drill li{padding:12px 10px;border:1px solid transparent;border-radius:6px;margin:8px 0}
.practice-drill .focused-item{border-color:var(--blue);background:var(--blue-soft)}

/* 独立重点入口复用目录按钮的选中/悬浮态；数字按知识点计数。 */
.review-entry{margin-bottom:18px;background:var(--white);border-color:var(--line);gap:12px}
.review-entry small{display:inline-block;min-width:22px;text-align:center;font-variant-numeric:tabular-nums}
.review-overview{display:flex;flex-wrap:wrap;gap:12px;margin:0 0 20px;color:var(--muted);font-size:12px}
.review-overview[hidden]{display:none}
.review-overview>span{padding:8px 14px;background:var(--white);border:1px solid var(--line);border-radius:6px}
.review-overview strong{color:var(--ink);margin-left:8px}
@media(max-width:740px){.review-entry{width:100%;margin-bottom:12px}.review-entry small{display:inline-block}}

/* 手机用标题按钮展开详情；桌面保留原题目布局，答案独立隐藏。 */
.question-toggle{display:none;background:transparent;color:var(--ink);padding:0;text-align:left;width:100%;font:inherit}
.question-toggle small{display:block;color:var(--muted);font-size:11px;font-weight:400;margin-top:4px}
.question-body[hidden]{display:none}
@media(max-width:740px){.question-title-text{display:none}.question-toggle{display:block;min-height:44px}.question-header{padding-bottom:18px}}

/* 手机目录使用页头右侧的 SVG 按钮；弹出列表复用已有目录选中样式。 */
.mobile-directory{display:none}
@media(max-width:740px){
 .topbar{position:sticky;top:0;z-index:4;height:64px;padding:0 18px;gap:8px}
 .mobile-directory{display:block;position:relative;flex-shrink:0}
 #directory-toggle{display:grid;place-items:center;width:44px;height:44px;padding:0;border:1px solid var(--line);border-radius:6px;background:var(--white);color:var(--ink)}
 #directory-panel{position:absolute;right:0;top:50px;display:grid;gap:6px;width:min(330px,calc(100vw - 36px));max-height:calc(100dvh - 84px);overflow:auto;overscroll-behavior:contain;padding:10px;border:1px solid var(--line);border-radius:8px;background:var(--white)}
 #directory-panel[hidden]{display:none}
 #directory-panel>.category{width:100%;white-space:normal;min-height:44px;font-size:13px}
 .sidebar{display:none}
 .question,.list-heading{scroll-margin-top:80px}
}