/* 学习空间：统一视觉层，保留原业务组件与主题选择。 */
:root { --paper:#f7f8f5; --ink:#253a35; --ink-soft:#596b65; --ink-faint:#75847e; --line:#e2e8e2; --card:#fff; --radius:18px; --shadow-lg:0 12px 40px -25px #254a3433; --shadow-md:0 4px 18px -12px #254a3426; }
:root:not([data-theme]), :root[data-theme="blue"] { --indigo:#287761; --violet:#236650; --pink:#287761; --c1:#287761; --c2:#236650; --c3:#287761; --grad:linear-gradient(#287761,#287761); --grad-soft:linear-gradient(#edf5ef,#edf5ef); --final-grad:linear-gradient(120deg,#e6f1e9,#f5f7ed); --glow:#28776130; --focus-border:#72a18d; --focus-strong:#287761; --focus-ring:#28776115; --live-border:#72a18d; --chip-hover:#edf5ef; --sel:#cfe7d7; }
.study-app { font-family: "PingFang SC","Microsoft YaHei",system-ui,sans-serif; background:var(--paper); }
.study-app a { text-underline-offset:4px; }
.study-app button,.study-app input,.study-app select,.study-app textarea { font-family:inherit; }
.study-app :focus-visible { outline:3px solid var(--focus-border); outline-offset:3px; }
.study-app .topbar { background:#fff; backdrop-filter:none; }
.study-app .topbar-inner { max-width:1080px; padding:17px 28px; }
.study-app .logo { background:var(--indigo); box-shadow:none; border-radius:14px; width:42px; height:42px; }
.study-app .brand-text { font-size:18px; line-height:1.4; }
.study-app .brand-text b { letter-spacing:0; font-size:11px; }
.study-app .icon-btn { width:auto; min-width:42px; height:40px; padding:0 9px; font-size:12px; border-radius:10px; }
.study-app .pill { padding:10px 14px; border-radius:11px; background:#f6f8f5; }
.study-app #statsBtn { display:none; }
.study-nav { display:flex; width:calc(100% - 56px); max-width:1024px; margin:0 auto; gap:30px; border-bottom:1px solid var(--line); }
.study-nav a { position:relative; display:flex; align-items:center; gap:9px; min-height:58px; padding:0 4px; color:var(--ink-soft); text-decoration:none; font-size:14px; }
.study-nav a[aria-current="page"] { color:var(--indigo); font-weight:700; }
.study-nav a[aria-current="page"]::after { content:''; position:absolute; height:3px; background:var(--indigo); bottom:-1px; left:0; right:0; border-radius:3px; }
.nav-number { font-size:10px; opacity:.6; font-variant-numeric:tabular-nums; }
.study-app .wrap { max-width:1080px; padding:0 28px 36px; }
.study-app .hero { display:grid; grid-template-columns:1.3fr 1fr; align-items:center; gap:56px; padding:44px 0 32px; text-align:left; }
.eyebrow { color:var(--indigo); font-size:12px; font-weight:600; letter-spacing:.08em; }
.status-dot { display:inline-block; height:6px; width:6px; margin:0 7px 2px 0; background:#c68c53; border-radius:50%; }
.study-app .hero h1 { font-family:inherit; font-size:42px; letter-spacing:-1.5px; line-height:1.45; margin:14px 0; font-weight:750; }
.study-app .hero h1 span { color:var(--indigo); }
.study-app .hero .sub { color:var(--ink-soft); font-size:14px; line-height:1.9; margin:0; }
.hero-note { max-width:350px; width:100%; justify-self:end; background:#eef2e9; border:1px solid #dfe7d9; border-radius:20px; padding:22px 25px; transform:rotate(2deg); }
.note-top { display:flex; align-items:center; gap:12px; font-size:13px; font-weight:600; }
.note-icon { display:grid; place-items:center; background:#dfe9d9; color:#426746; width:43px; height:43px; border-radius:13px; font:bold italic 28px Georgia,serif; }
.note-top small { display:block; margin-top:5px; font-size:10px; font-weight:400; color:var(--ink-soft); }
.note-path { display:flex; flex-direction:column; align-items:flex-start; margin:18px 0 16px 8px; font-size:13px; }
.note-path span { display:flex; gap:14px; align-items:center; }
.note-path b { color:#879980; font-size:10px; font-weight:500; }
.note-path i { color:#a6b6a0; margin:3px 0 3px 36px; font-size:12px; font-style:normal; }
.note-bottom { border-top:1px dashed #ccd8c4; padding-top:12px; font-size:11px; color:#6b7f60; display:flex; justify-content:space-between; }
.note-bottom span { color:#bb8551; }
.study-app .ask-card { position:relative; background:white; border:1px solid var(--line); border-radius:22px; padding:24px; backdrop-filter:none; box-shadow:var(--shadow-lg); }
.section-kicker { display:flex; justify-content:space-between; align-items:center; font-size:15px; font-weight:600; margin-bottom:18px; }
.quiet-tag { font-size:11px; color:var(--indigo); background:var(--theme-soft,#edf5ef); padding:5px 9px; font-weight:400; border-radius:6px; }
.study-app .ask-card textarea { min-height:105px; font-size:17px; line-height:1.9; }
.study-app .ask-card textarea::placeholder { color:#7b8780; }
.study-app .ask-head-row { margin:0 0 8px; }
.study-app .max-credits { color:var(--ink-soft); font-size:12px; }
.study-app .max-credits,.study-app .mc-sel { background:#f5f7f2; border-color:var(--line); box-shadow:none; }
.study-app .max-credits select { color:var(--indigo); }
.study-app .chips { gap:6px; margin:12px 0 18px; }
.study-app .chip { background:#f8faf7; border:1px solid #e9eee7; border-radius:7px; font-size:12px; padding:7px 10px; }
.study-app .ask-row { border-top:1px solid #edf0eb; padding-top:16px; }
.study-app .ask-row .btn { flex:none; border-radius:10px; min-height:44px; }
.study-app .ask-row .btn.primary { margin-right:auto; flex-basis:auto; }
.study-app .btn { text-decoration:none; }
.study-app .btn.primary { background:var(--indigo); box-shadow:none; border-color:transparent; }
.study-app .btn.primary:hover { background:var(--violet); transform:none; }
.study-app .btn-spark { animation:none; }
.study-app .btn.ghost { border:0; background:#f4f7f2; font-size:13px; padding:11px 14px; }
.study-app #clearBtn { background:transparent; color:var(--ink-faint); padding:10px 8px; font-size:12px; }
.learning-strip { font-size:12px; color:var(--ink-soft); padding:19px 2px; line-height:1.8; }
.study-app .home-banners { display:grid; grid-template-columns:1fr 1fr; gap:18px; margin-top:0; }
.learning-card { display:flex; gap:18px; padding:25px; background:#fff; border:1px solid var(--line); border-radius:18px; color:var(--ink); text-decoration:none; transition:border-color .2s; }
.learning-card:hover { border-color:#9bb5a6; }
.card-symbol { flex:none; width:43px; height:46px; border-radius:12px; display:grid; place-items:center; color:#806c47; background:#f6efdf; font-size:25px; }
.teacher-card .card-symbol { color:#477a61; background:#e7f1e8; font-family:Georgia,serif; font-style:italic; }
.learning-card .eyebrow { color:var(--ink-faint); font-size:10px; }
.learning-card h2 { font-size:18px; margin:8px 0; font-weight:650; }
.learning-card p { font-size:13px; color:var(--ink-soft); line-height:1.85; margin:0 0 17px; }
.text-link { font-size:12px; color:var(--indigo); }
.text-link b { padding-left:8px; }
.study-app .footer { text-align:center; padding:20px 20px 35px; color:#7d8981; font-size:11px; }
.study-app .footer p { margin:0 0 5px; }
.study-app .footer span { font-size:10px; }
.study-app .page-hero { margin:0; padding:34px 0 24px; }
.study-app .page-hero h1 { font-size:28px; margin:9px 0 10px; letter-spacing:-.5px; font-weight:700; }
.study-app .page-hero .sub { font-size:13px; line-height:1.85; color:var(--ink-soft); }
.study-app .page-hero .btn { font-size:13px; padding:12px 16px; border-radius:10px; }
.study-metrics { display:grid; grid-template-columns:repeat(4,1fr); background:white; border:1px solid var(--line); border-radius:16px; padding:21px 0; }
.study-metrics>div { padding:0 22px; border-right:1px solid var(--line); }
.study-metrics>div:last-child { border:0; }
.study-metrics span,.study-metrics small { display:block; font-size:12px; color:var(--ink-soft); }
.study-metrics strong { display:block; font-size:29px; font-weight:650; margin:8px 0 5px; color:var(--indigo); font-variant-numeric:tabular-nums; }
.study-metrics small { font-size:10px; color:var(--ink-faint); }
.notebook-toolbar { display:flex; justify-content:space-between; gap:15px; align-items:center; margin:26px 0 12px; }
.filter-tabs { display:flex; gap:5px; background:#eaf0e7; padding:4px; border-radius:10px; }
.filter-tabs button { background:transparent; border:0; border-radius:7px; color:var(--ink-soft); padding:10px 17px; cursor:pointer; font-size:13px; }
.filter-tabs button[aria-pressed="true"] { background:#fff; color:var(--indigo); box-shadow:0 2px 5px #273e3510; font-weight:600; }
.search-field { display:flex; gap:8px; align-items:center; font-size:12px; color:var(--ink-soft); }
.search-field input { background:#fff; border:1px solid var(--line); padding:10px 12px; border-radius:9px; min-width:0; }
.notebook-note { font-size:11px; line-height:1.8; color:var(--ink-faint); margin:12px 0 18px; }
.study-app .wrong-list { display:grid; gap:14px; }
.study-app .wrong-item { padding:23px; background:#fff; border:1px solid var(--line); border-radius:15px; box-shadow:none; }
.study-app .wrong-item-head { align-items:flex-start; gap:12px; }
.study-app .wrong-q { font-size:16px; line-height:1.8; font-weight:600; overflow-wrap:anywhere; }
.wrong-meta { display:flex; gap:8px; flex-wrap:wrap; font-size:11px; color:var(--ink-faint); margin-bottom:12px; }
.review-badge { background:#f3f5f0; border-radius:5px; padding:3px 7px; }
.review-badge.good { color:var(--indigo); background:var(--theme-soft,#edf5ef); }
.review-badge.retry { color:#9c6742; background:#fbf1e6; }
.study-app .wrong-item summary { color:var(--indigo); padding:16px 0; font-size:13px; cursor:pointer; }
.study-app .wb-answer { background:#f7f9f5; padding:18px; font-size:15px; line-height:1.9; border-radius:10px; overflow-wrap:anywhere; }
.review-row { margin-top:16px; padding-top:14px; border-top:1px solid #edf1e9; display:flex; align-items:center; gap:7px; flex-wrap:wrap; font-size:12px; color:var(--ink-soft); }
.review-row button,.wrong-actions button,.wrong-actions a { min-height:38px; border:1px solid var(--line); border-radius:8px; padding:8px 11px; background:white; color:var(--ink-soft); font-size:12px; cursor:pointer; text-decoration:none; }
.review-row button[aria-pressed="true"] { color:var(--indigo); background:var(--theme-soft,#edf5ef); border-color:#9cb8a8; }
.study-app .wrong-actions { display:flex; flex-wrap:wrap; gap:8px; margin-top:12px; }
.study-app .wrong-actions .ask-teacher { color:var(--indigo); background:var(--theme-soft,#edf5ef); border-color:transparent; }
.study-app .wrong-actions .delete-record { margin-left:auto; color:#8e6a62; border-color:transparent; }
.wrong-reason { display:flex; align-items:center; gap:8px; margin-top:12px; font-size:12px; color:var(--ink-soft); }
.wrong-reason select { max-width:100%; border:1px solid var(--line); border-radius:7px; padding:8px; background:white; color:var(--ink-soft); }
.teacher-inline,.record-followup { display:flex; align-items:center; justify-content:space-between; gap:16px; padding:20px; border:1px solid #d9e7da; background:var(--theme-soft,#edf5ef); border-radius:14px; margin:20px 0; font-size:13px; text-decoration:none; color:var(--indigo); }
.record-followup p { font-size:12px; color:var(--ink-soft); margin:6px 0 0; }
.record-followup a { flex-shrink:0; color:var(--indigo); text-decoration:none; }
.study-app .empty-hint { padding:42px 20px; text-align:center; line-height:1.9; border:1px dashed #ccd9cd; border-radius:16px; background:#fbfcf9; }
.study-app .empty-hint a { color:var(--indigo); }
.study-app .step-card,.study-app .final-card,.study-app .chart-card,.study-app .stat-card { box-shadow:none; border:1px solid var(--line); background:#fff; }
.study-app .step-card { border-radius:16px; }
.study-app .step-title { font-family:inherit; }
.study-app .step-card .step-body { line-height:1.95; }
.study-app .stat-num { color:var(--indigo); background:none; -webkit-text-fill-color:currentColor; }
.study-app .chat-banner { background:var(--theme-soft,#edf5ef); color:var(--ink); box-shadow:none; border:1px solid var(--line); }
.study-app .chat-banner-desc { color:var(--ink-soft); }
.study-app .chat-page-main { max-width:1024px; height:calc(100dvh - 136px); min-height:570px; padding:0 20px; }
.teacher-intro { display:flex; gap:16px; align-items:center; padding:26px 0 18px; flex-shrink:0; }
.teacher-mark { position:relative; display:grid; place-items:center; flex-shrink:0; width:58px; height:58px; border-radius:20px; background:#e3eddd; color:#487148; font:bold italic 36px Georgia,serif; }
.teacher-mark span { position:absolute; bottom:2px; right:2px; width:11px; height:11px; border:2px solid var(--paper); background:#5b9a73; border-radius:50%; }
.teacher-intro h1 { font-size:23px; margin:6px 0; font-weight:650; }
.teacher-intro p { font-size:12px; color:var(--ink-soft); margin:0; line-height:1.7; }
.teacher-context { padding:11px 14px; color:var(--ink-soft); background:#edf2e9; border:1px solid #e1e8dc; border-radius:9px; font-size:12px; line-height:1.7; flex-shrink:0; }
.teacher-prompts { display:flex; gap:8px; margin:12px 0; flex-shrink:0; }
.teacher-prompts button { flex:1; text-align:left; border:1px solid var(--line); background:white; padding:13px; border-radius:10px; color:var(--ink-soft); cursor:pointer; font-size:12px; }
.teacher-prompts button:hover { border-color:var(--indigo); }
.teacher-prompts span { float:right; color:var(--indigo); }
.study-app .chat-cap-row { display:flex; justify-content:space-between; align-items:center; padding:5px 0 9px; }
.chat-usage-note { font-size:10px; color:var(--ink-faint); }
.study-app .chat-page-main .chat-body { background:#fff; border:1px solid var(--line); border-radius:14px 14px 0 0; padding:20px; min-height:100px; }
.study-app .chat-avatar { background:#e7f0e2; color:#487148; border-radius:11px; }
.study-app .chat-bubble { box-shadow:none; border:0; background:#f5f7f2; font-size:15px; line-height:1.9; max-width:85%; padding:14px 18px; }
.study-app .chat-msg.user .chat-bubble { background:#e5efe7; color:var(--ink); }
.study-app .chat-bubble { min-width:0; overflow-wrap:anywhere; }
.study-app .chat-input-row { flex-shrink:0; border:1px solid var(--line); border-top:0; border-radius:0 0 14px 14px; background:white; padding:13px; margin-bottom:15px; }
.study-app .chat-input-row textarea { border:0; background:#f5f7f2; border-radius:9px; font-size:16px; }
.study-app .chat-input-row .btn { border-radius:9px; padding:12px 20px; }
.teacher-welcome { margin:auto; max-width:430px; text-align:center; padding:24px 12px; }
.teacher-welcome strong { display:block; font-size:18px; margin-bottom:12px; color:var(--ink); }
.teacher-welcome p { font-size:13px; line-height:1.9; color:var(--ink-soft); }
.study-app .cost-box { background:var(--theme-soft,#edf5ef); color:var(--ink-soft); border-color:var(--line); text-align:right; font-weight:400; }
.compact-chat .teacher-context,.compact-chat .teacher-prompts,.compact-chat .teacher-intro p { display:none; }
.compact-chat .teacher-intro { padding:8px 0; }
.compact-chat .teacher-intro h1 { font-size:16px; }
.compact-chat .teacher-mark { width:34px; height:34px; font-size:24px; }
@media (max-width:700px) {
  .study-app .topbar-inner { padding:10px 16px; }
  .study-app .brand-text { font-size:16px; }
  .study-app .brand-text b { display:none; }
  .study-app .logo { width:35px; height:35px; font-size:23px; border-radius:11px; }
  .study-app .icon-btn { min-width:36px; height:38px; padding:0 5px; font-size:11px; }
  .study-app .pill { max-width:34vw; font-size:12px; padding:9px; }
  .study-app .topbar-right { gap:3px; }
  .study-nav { position:fixed; width:auto; z-index:70; bottom:0; left:0; right:0; margin:0; background:#fff; border-top:1px solid var(--line); border-bottom:0; justify-content:space-around; gap:0; padding:5px 8px calc(5px + env(safe-area-inset-bottom)); }
  .study-nav a { flex:1; min-height:49px; padding:7px 0; justify-content:center; flex-direction:column; gap:4px; font-size:11px; }
  .nav-number { font-size:10px; letter-spacing:.12em; }
  .study-nav a[aria-current="page"] { background:var(--theme-soft,#edf5ef); border-radius:9px; }
  .study-nav a[aria-current="page"]::after { display:none; }
  .study-app .wrap { padding:0 16px 25px; }
  .study-app { padding-bottom:calc(70px + env(safe-area-inset-bottom)); }
  .study-app .hero { display:block; padding:27px 2px 23px; }
  .study-app .hero h1 { font-size:30px; letter-spacing:-.7px; margin:12px 0; }
  .study-app .hero .sub { padding:0; font-size:12px; }
  .hero-note { display:none; }
  .eyebrow { font-size:11px; }
  .study-app .ask-card { padding:18px 15px; border-radius:16px; }
  .section-kicker { font-size:13px; margin-bottom:12px; gap:8px; }
  .quiet-tag { font-size:10px; padding:4px 6px; }
  .study-app .ask-card textarea { min-height:95px; font-size:16px; }
  .study-app .ask-row { gap:7px; }
  .study-app .ask-row .btn.primary { flex-basis:100%; margin:0; order:4; }
  .study-app .ask-row .btn.ghost { flex:1; padding:9px 6px; font-size:12px; }
  .study-app .ask-row #clearBtn { flex:0 0 auto; }
  .study-app .home-banners { grid-template-columns:1fr; gap:12px; }
  .learning-card { padding:19px; gap:14px; border-radius:14px; }
  .learning-card h2 { font-size:17px; }
  .learning-card p { margin-bottom:12px; font-size:12px; }
  .learning-card p br { display:none; }
  .learning-strip { font-size:11px; padding:14px 0; }
  .study-app .page-hero { padding:26px 0 18px; }
  .study-app .page-hero h1 { font-size:23px; }
  .study-app .page-hero .sub { font-size:12px; }
  .study-metrics { grid-template-columns:1fr 1fr; padding:4px 0; }
  .study-metrics>div { padding:16px; }
  .study-metrics>div:nth-child(2) { border:0; }
  .study-metrics strong { font-size:26px; }
  .notebook-toolbar { flex-wrap:wrap; margin-top:20px; }
  .filter-tabs { width:100%; }
  .filter-tabs button { flex:1; padding:10px; font-size:12px; }
  .search-field { width:100%; }
  .search-field input { flex:1; font-size:16px; width:100%; }
  .study-app .wrong-item { padding:17px; }
  .study-app .wrong-q { font-size:15px; }
  .study-app .wrong-item-head { display:block; }
  .study-app .wrong-date { margin-top:6px; }
  .study-app .wb-answer { padding:13px; font-size:14px; }
  .study-app .wrong-actions button,.study-app .wrong-actions a { min-height:42px; }
  .teacher-inline,.record-followup { padding:16px; font-size:12px; flex-wrap:wrap; }
  .study-app .chat-page-main { height:calc(100dvh - 125px - env(safe-area-inset-bottom)); min-height:460px; padding:0 12px; }
  .teacher-intro { padding:17px 2px 12px; gap:12px; }
  .teacher-mark { width:43px; height:43px; font-size:29px; border-radius:14px; }
  .teacher-intro h1 { font-size:19px; }
  .teacher-intro p { font-size:10px; }
  .teacher-context { padding:8px 10px; font-size:10px; }
  .teacher-prompts { gap:5px; margin:9px 0; }
  .teacher-prompts button { padding:10px 5px; font-size:10px; text-align:center; }
  .teacher-prompts span { display:none; }
  .chat-usage-note { font-size:9px; }
  .study-app .chat-page-main .chat-body { padding:13px 9px; }
  .study-app .chat-bubble { font-size:14px; padding:11px 13px; }
  .study-app .chat-input-row { padding:9px; margin-bottom:5px; }
  .study-app .chat-input-row .btn { padding:11px 12px; }
  .teacher-welcome strong { font-size:16px; }
  .teacher-welcome p { font-size:12px; }
  .study-app .toast { bottom:calc(85px + env(safe-area-inset-bottom)); }
}
@media (prefers-reduced-motion:reduce) { .study-app *, .study-app *::before,.study-app *::after { animation:none!important; transition:none!important; scroll-behavior:auto!important; } }

.mastery-metrics { grid-template-columns:repeat(3,1fr); }
@media(max-width:640px){ .mastery-metrics>div{padding:14px 10px;} .mastery-metrics>div:nth-child(2){border-right:1px solid var(--line);} }

.recharge-gift { margin:12px 0 18px; padding:17px; background:#f3f7f1; border:1px solid #dce7da; border-radius:14px; color:var(--ink); }
.recharge-gift[hidden] { display:none; }
.recharge-gift-head { display:flex; flex-wrap:wrap; align-items:center; justify-content:space-between; gap:6px 12px; font-size:11px; color:var(--ink-soft); }
.recharge-gift-head strong { font-size:12px; color:var(--indigo); font-weight:600; }
.recharge-gift-next { margin:13px 0 12px; font-size:17px; font-weight:600; line-height:1.5; }
.recharge-gift-next b { color:var(--indigo); font-variant-numeric:tabular-nums; }
.recharge-gift-track { height:9px; border-radius:12px; background:#dee9dc; overflow:hidden; }
.recharge-gift-track>span { display:block; height:100%; border-radius:inherit; background:var(--indigo); }
.recharge-gift-scale { margin:7px 0 12px; display:flex; flex-wrap:wrap; justify-content:space-between; gap:5px 12px; font-size:11px; color:var(--ink-soft); font-variant-numeric:tabular-nums; }
.recharge-gift p { margin:0; font-size:12px; line-height:1.7; }
.recharge-gift small { display:block; margin-top:4px; font-size:11px; line-height:1.6; color:var(--ink-soft); }
.photo-context{display:flex;align-items:center;gap:12px;margin:12px 0;background:#f0f5ed;border:1px solid #dce7d7;border-radius:12px;padding:12px}.photo-context[hidden],.photo-status[hidden]{display:none}.photo-context img{width:60px;height:60px;object-fit:contain;background:#fff;border-radius:7px;flex:none}.photo-context div{flex:1;min-width:0}.photo-context strong{font-size:12px;color:var(--indigo)}.photo-context p,.photo-status{font-size:12px;line-height:1.8;color:#596b65;margin:4px 0}.photo-context button{border:0;background:transparent;color:#596b65;font-size:12px;padding:8px;cursor:pointer;flex:none}.photo-status{margin:10px 0}.study-app button:disabled{opacity:.55;cursor:wait}@media(max-width:480px){.photo-context{flex-wrap:wrap}.photo-context div{min-width:150px}.photo-context button{margin-left:auto}}
.study-chat .chat-page-main{min-height:0;box-sizing:border-box}.study-chat .chat-input-row{display:flex;flex-direction:column;gap:8px;padding:12px 14px;border-top:1px solid #e5ebe1}.study-chat .chat-cap-row{width:100%;margin:0;padding:0;flex-shrink:0;gap:8px}.study-chat .chat-compose-line{width:100%;display:flex;align-items:flex-end;gap:10px;min-width:0}.study-chat .chat-compose-line textarea{box-sizing:border-box;min-width:0;min-height:48px;max-height:144px;padding:12px;line-height:1.65;resize:none;margin:0;font-size:16px;flex:1}.study-chat .chat-compose-line .btn{min-height:48px;min-width:64px;flex:none;align-self:flex-end}.chat-compose-hint{font-size:10px;color:#75847e;line-height:1.6;margin:0;width:100%}.study-chat .teacher-prompts button{line-height:1.6;min-height:44px}.study-chat .chat-page-main .chat-body{min-height:0;overscroll-behavior:contain;scroll-padding:15px}.study-chat .chat-bubble{max-width:calc(100% - 42px)}@media(max-width:700px){body.study-chat{padding-bottom:0;overflow:hidden}.study-chat .teacher-intro{padding:14px 2px 10px;gap:10px}.study-chat .teacher-intro h1{font-size:18px}.study-chat .teacher-intro p{font-size:11px}.study-chat .teacher-context{font-size:11px}.study-chat .teacher-prompts{margin:8px 0}.study-chat .teacher-prompts button{font-size:11px;padding:8px 5px}.study-chat .chat-input-row{padding:10px;margin-bottom:4px;gap:7px}.study-chat .chat-cap-row .chat-usage-note{font-size:10px}.study-chat .chat-cap-row .max-credits{font-size:11px}.study-chat .chat-compose-line textarea{font-size:16px}.study-chat .chat-bubble{font-size:15px}.study-chat.chat-editing .study-nav,.study-chat.chat-editing .teacher-intro,.study-chat.chat-editing .teacher-context,.study-chat.chat-editing .teacher-prompts,.study-chat.chat-editing .chat-compose-hint,.study-chat.chat-editing .pet-launch{display:none}.study-chat.chat-editing .chat-input-row{padding-bottom:max(10px,env(safe-area-inset-bottom))}.study-chat .chat-page-main{padding:0 10px}.study-chat .teacher-welcome{padding:14px 8px}.study-chat .teacher-welcome strong{font-size:16px}.study-chat .teacher-welcome p{font-size:12px}}
.study-chat.chat-editing aside[aria-label="版本更新"]{display:none!important}
.study-chat .teacher-intro>div:nth-child(2){min-width:0;flex:1}.study-chat .teacher-intro .pet-widget{position:static;flex:none;margin-left:auto}.study-chat .teacher-intro .pet-launch{width:44px;height:44px;min-width:44px;box-sizing:border-box;padding:2px;border-radius:12px;box-shadow:none}.study-chat .teacher-intro .pet-icon{width:36px;height:36px}.study-chat .teacher-intro .pet-label{display:none}.study-chat .pet-panel{position:fixed;top:80px;right:18px;bottom:auto;max-height:calc(100dvh - 100px);margin:0}.study-chat .pet-panel h3{font-family:inherit}@media(max-width:640px){.study-chat .pet-panel{top:calc(var(--pet-viewport-top,0px) + 12px + env(safe-area-inset-top));right:12px;left:12px;margin:0 auto;max-height:calc(var(--pet-viewport-height,100dvh) - 24px - env(safe-area-inset-top) - env(safe-area-inset-bottom))}}

/* Teacher explanations: readable steps and receipts on narrow screens. */
.study-app .chat-msg.assistant .chat-bubble { white-space:normal; }
.study-app .chat-bubble :is(h1,h2,h3,h4) { font-size:16px; line-height:1.6; color:var(--ink); margin:20px 0 9px; font-weight:650; }
.study-app .chat-bubble > :first-child { margin-top:0; }
.study-app .chat-bubble p { margin:0 0 12px; }
.study-app .chat-bubble :is(ul,ol) { padding-left:23px; margin:10px 0 14px; }
.study-app .chat-bubble li { margin:7px 0; padding-left:3px; }
.study-app .chat-bubble li::marker { color:var(--green, #487148); font-weight:600; }
.study-app .chat-bubble blockquote { margin:14px 0; border-left:3px solid #aac4aa; padding:8px 12px; background:#edf3e9; }
.study-app .chat-bubble .katex-display { overflow-x:auto; overflow-y:hidden; max-width:100%; padding:8px 0; margin:12px 0; }
.study-app .chat-cost { border-top:1px solid #dfe7dc; margin-top:16px; padding-top:10px; font-size:12px; line-height:1.7; color:var(--ink-soft); font-variant-numeric:tabular-nums; }
.study-app .chat-cost details { margin-top:7px; }
.study-app .chat-cost summary { cursor:pointer; color:#487148; }
.study-app .chat-cost details p { margin:7px 0 0; font-size:11px; }

.study-app .msg-item-head { flex-wrap:wrap; align-items:baseline; }

/* On phones, the conversation is the main reading surface. */
.teacher-tools-toggle { display:none; }
@media (max-width:700px) {
  .study-chat .topbar-inner { padding:8px 12px; }
  .study-chat .topbar .icon-btn { height:36px; }
  .study-chat .chat-page-main { padding:0 6px; }
  .study-chat .teacher-intro { padding:5px 6px; gap:8px; min-height:44px; }
  .study-chat .teacher-intro .teacher-mark,
  .study-chat .teacher-intro .eyebrow,
  .study-chat .teacher-intro p,
  .study-chat .teacher-title-extra { display:none; }
  .study-chat .teacher-intro h1 { font-size:16px; margin:0; }
  .study-chat .teacher-intro .pet-launch { width:36px; height:36px; min-width:36px; border-radius:10px; }
  .study-chat .teacher-intro .pet-icon { width:30px; height:30px; }
  .study-chat.chat-has-messages .teacher-tools-toggle { display:inline-flex; align-items:center; min-height:36px; padding:6px 10px; border:1px solid var(--line); border-radius:9px; background:#fff; color:var(--indigo); font-size:12px; flex:none; cursor:pointer; }
  .study-chat.chat-has-messages:not(.chat-tools-open) .teacher-context,
  .study-chat.chat-has-messages:not(.chat-tools-open) .teacher-prompts { display:none; }
  .study-chat .chat-page-main .chat-body { padding:14px 10px; border-radius:12px 12px 0 0; gap:20px; }
  .study-chat .chat-msg.assistant { display:block; }
  .study-chat .chat-msg.assistant .chat-avatar { display:none; }
  .study-chat .chat-msg.assistant .chat-bubble { width:100%; max-width:100%; box-sizing:border-box; padding:4px 2px 12px; background:transparent; border-radius:0; font-size:16px; line-height:1.9; }
  .study-chat .chat-msg.user .chat-bubble { max-width:90%; font-size:15px; }
  .study-chat .chat-input-row { padding:7px 9px; gap:5px; margin-bottom:2px; }
  .study-chat .chat-compose-hint { display:none; }
  .study-chat .chat-cap-row .chat-usage-note { font-size:9px; line-height:1.4; }
  .study-chat .chat-compose-line textarea { min-height:44px; padding:9px 11px; }
  .study-chat .chat-compose-line .btn { min-height:44px; }
}

.scan-invite-note { font-size:12px; line-height:1.8; padding:10px 12px; border-radius:9px; background:var(--theme-soft,#edf5ef); color:#487148; margin:8px 0; }
#regInvite[readonly] { background:var(--theme-soft,#edf5ef); color:var(--indigo); font-weight:600; }

/* Coordinated, low saturation accents; legacy theme keys preserve saved preferences. */
:root[data-theme="blue"]{--indigo:#287761;--violet:#236650;--pink:#287761;--c1:#287761;--c2:#236650;--c3:#287761;--theme-note:#eef2e9;--theme-context:#edf2e9;--theme-note-edge:#dfe7d9;--theme-context-edge:#e1e8dc;--theme-soft:#edf5ef;--theme-edge:#cfe7d7;--grad:linear-gradient(#287761,#287761);--grad-soft:linear-gradient(#edf5ef,#edf5ef);--final-grad:linear-gradient(120deg,#cfe7d7,#edf5ef);--timeline-grad:linear-gradient(180deg,#72a18d,#cfe7d7 92%,transparent);--blob1:#cfe7d7;--blob2:#edf5ef;--blob3:#cfe7d7;--chip-hover:#edf5ef;--spinner-track:#cfe7d7;--focus-border:#72a18d;--focus-strong:#287761;--focus-ring:#28776115;--live-border:#72a18d;--sel:#cfe7d7;--glow:#28776130;--glow-strong:#28776140}
:root[data-theme="indigo"]{--indigo:#52648c;--violet:#415376;--pink:#52648c;--c1:#52648c;--c2:#415376;--c3:#52648c;--theme-soft:#eff2f8;--theme-edge:#dce3f0;--grad:linear-gradient(#52648c,#52648c);--grad-soft:linear-gradient(#eff2f8,#eff2f8);--final-grad:linear-gradient(120deg,#dce3f0,#eff2f8);--timeline-grad:linear-gradient(180deg,#8e9cbb,#dce3f0 92%,transparent);--blob1:#dce3f0;--blob2:#eff2f8;--blob3:#dce3f0;--chip-hover:#eff2f8;--spinner-track:#dce3f0;--focus-border:#8e9cbb;--focus-strong:#52648c;--focus-ring:#52648c15;--live-border:#8e9cbb;--sel:#dce3f0;--glow:#52648c30;--glow-strong:#52648c40}
:root[data-theme="purple"]{--indigo:#786092;--violet:#644e7c;--pink:#786092;--c1:#786092;--c2:#644e7c;--c3:#786092;--theme-soft:#f4f0f7;--theme-edge:#e9def0;--grad:linear-gradient(#786092,#786092);--grad-soft:linear-gradient(#f4f0f7,#f4f0f7);--final-grad:linear-gradient(120deg,#e9def0,#f4f0f7);--timeline-grad:linear-gradient(180deg,#ab97bf,#e9def0 92%,transparent);--blob1:#e9def0;--blob2:#f4f0f7;--blob3:#e9def0;--chip-hover:#f4f0f7;--spinner-track:#e9def0;--focus-border:#ab97bf;--focus-strong:#786092;--focus-ring:#78609215;--live-border:#ab97bf;--sel:#e9def0;--glow:#78609230;--glow-strong:#78609240}
:root[data-theme="ocean"]{--indigo:#317a86;--violet:#266672;--pink:#317a86;--c1:#317a86;--c2:#266672;--c3:#317a86;--theme-soft:#edf5f6;--theme-edge:#d4e9ec;--grad:linear-gradient(#317a86,#317a86);--grad-soft:linear-gradient(#edf5f6,#edf5f6);--final-grad:linear-gradient(120deg,#d4e9ec,#edf5f6);--timeline-grad:linear-gradient(180deg,#84adb5,#d4e9ec 92%,transparent);--blob1:#d4e9ec;--blob2:#edf5f6;--blob3:#d4e9ec;--chip-hover:#edf5f6;--spinner-track:#d4e9ec;--focus-border:#84adb5;--focus-strong:#317a86;--focus-ring:#317a8615;--live-border:#84adb5;--sel:#d4e9ec;--glow:#317a8630;--glow-strong:#317a8640}
:root[data-theme="forest"]{--indigo:#65743d;--violet:#53622e;--pink:#65743d;--c1:#65743d;--c2:#53622e;--c3:#65743d;--theme-soft:#f2f5eb;--theme-edge:#e1e8ce;--grad:linear-gradient(#65743d,#65743d);--grad-soft:linear-gradient(#f2f5eb,#f2f5eb);--final-grad:linear-gradient(120deg,#e1e8ce,#f2f5eb);--timeline-grad:linear-gradient(180deg,#9fab7d,#e1e8ce 92%,transparent);--blob1:#e1e8ce;--blob2:#f2f5eb;--blob3:#e1e8ce;--chip-hover:#f2f5eb;--spinner-track:#e1e8ce;--focus-border:#9fab7d;--focus-strong:#65743d;--focus-ring:#65743d15;--live-border:#9fab7d;--sel:#e1e8ce;--glow:#65743d30;--glow-strong:#65743d40}
:root[data-theme="sunset"]{--indigo:#a65b32;--violet:#8e4827;--pink:#a65b32;--c1:#a65b32;--c2:#8e4827;--c3:#a65b32;--theme-soft:#fcf2eb;--theme-edge:#f4ddcd;--grad:linear-gradient(#a65b32,#a65b32);--grad-soft:linear-gradient(#fcf2eb,#fcf2eb);--final-grad:linear-gradient(120deg,#f4ddcd,#fcf2eb);--timeline-grad:linear-gradient(180deg,#ca997c,#f4ddcd 92%,transparent);--blob1:#f4ddcd;--blob2:#fcf2eb;--blob3:#f4ddcd;--chip-hover:#fcf2eb;--spinner-track:#f4ddcd;--focus-border:#ca997c;--focus-strong:#a65b32;--focus-ring:#a65b3215;--live-border:#ca997c;--sel:#f4ddcd;--glow:#a65b3230;--glow-strong:#a65b3240}
:root[data-theme="sakura"]{--indigo:#a15878;--violet:#894461;--pink:#a15878;--c1:#a15878;--c2:#894461;--c3:#a15878;--theme-soft:#fbf0f5;--theme-edge:#f0d8e3;--grad:linear-gradient(#a15878,#a15878);--grad-soft:linear-gradient(#fbf0f5,#fbf0f5);--final-grad:linear-gradient(120deg,#f0d8e3,#fbf0f5);--timeline-grad:linear-gradient(180deg,#c892aa,#f0d8e3 92%,transparent);--blob1:#f0d8e3;--blob2:#fbf0f5;--blob3:#f0d8e3;--chip-hover:#fbf0f5;--spinner-track:#f0d8e3;--focus-border:#c892aa;--focus-strong:#a15878;--focus-ring:#a1587815;--live-border:#c892aa;--sel:#f0d8e3;--glow:#a1587830;--glow-strong:#a1587840}
:root[data-theme="crimson"]{--indigo:#a65048;--violet:#8d413b;--pink:#a65048;--c1:#a65048;--c2:#8d413b;--c3:#a65048;--theme-soft:#fbf0ee;--theme-edge:#f1d7d3;--grad:linear-gradient(#a65048,#a65048);--grad-soft:linear-gradient(#fbf0ee,#fbf0ee);--final-grad:linear-gradient(120deg,#f1d7d3,#fbf0ee);--timeline-grad:linear-gradient(180deg,#c58c85,#f1d7d3 92%,transparent);--blob1:#f1d7d3;--blob2:#fbf0ee;--blob3:#f1d7d3;--chip-hover:#fbf0ee;--spinner-track:#f1d7d3;--focus-border:#c58c85;--focus-strong:#a65048;--focus-ring:#a6504815;--live-border:#c58c85;--sel:#f1d7d3;--glow:#a6504830;--glow-strong:#a6504840}
.study-app .theme-swatches{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:8px 0 22px}
.study-app .theme-swatch{display:flex;align-items:center;gap:9px;position:relative;width:100%;height:auto;min-height:48px;padding:10px;border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--ink-soft);font-size:12px;text-align:left;box-shadow:none;transform:none}
.study-app .theme-swatch::before{content:'';width:21px;height:21px;flex:none;background:var(--swatch);border-radius:50%;box-shadow:inset 0 0 0 1px #0000000c}
.study-app .theme-swatch.active{border-color:var(--indigo);background:var(--theme-soft,#edf5ef);color:var(--indigo);font-weight:600}
.study-app .theme-swatch.active::after{content:'✓';margin-left:auto;font-size:14px}
.study-app .theme-swatch:hover{border-color:var(--focus-border)}
.study-app .hero-note{background:var(--theme-note,var(--theme-soft,#eef2e9));border-color:var(--theme-note-edge,var(--theme-edge,#dfe7d9))}
.study-app .teacher-context{background:var(--theme-context,var(--theme-soft,#edf2e9));border-color:var(--theme-context-edge,var(--theme-edge,#e1e8dc))}
.study-app .teacher-mark span{background:var(--indigo)}
:root[data-theme]:not([data-theme=blue]) .study-app #result{--solve-green:var(--indigo)}
:root[data-theme]:not([data-theme=blue]) .study-app #result :is(.final-head h3,.k-head-row h3,.solution-section-heading,.k-name,.solution-action,.solution-action span){color:var(--indigo)}
:root[data-theme]:not([data-theme=blue]) .study-app #result :is(.final-card,.insight-card,.final-badge,.k-icon,.step-num,.solution-section-heading span){background:var(--theme-soft);border-color:var(--theme-edge)}
:root[data-theme]:not([data-theme=blue]) .study-app #result .solution-action:hover{background:var(--theme-soft);border-color:var(--focus-border)}
.study-app #result .solution-action:focus-visible{outline-color:var(--indigo)}
:root[data-theme]:not([data-theme=blue]) .study-app :is(.note-icon,.teacher-card .card-symbol){background:var(--theme-edge);color:var(--indigo)}
:root[data-theme]:not([data-theme=blue]) .study-app :is(.note-path b,.note-bottom){color:var(--ink-soft)}
:root[data-theme]:not([data-theme=blue]) .study-app .note-bottom{border-color:var(--theme-edge)}

/* Optional manual referral stays folded; scanned attribution is hidden. */
#inviteDetails{border:1px solid var(--line,#dce5de);border-radius:12px;padding:12px 14px;margin:14px 0}#inviteDetails[hidden]{display:none}#inviteDetails summary{cursor:pointer;font-size:13px;color:var(--muted,#64776d)}#inviteDetails[open] summary{margin-bottom:12px}