/* S12 · 手机续学与三条学习线（/subjective-mobile）
   仅作用在 .s12-root 内；body.s12-focus-body 只用于聚焦版式（统一顶栏、无桌面侧栏）。 */
.s12-root{
  --s12-teal:#0b7775;--s12-teal-2:#1aaaa1;--s12-line:#dbe6ea;--s12-hover:#f2fbfa;
  --s12-ink:#11283a;--s12-muted:#526976;--s12-soft:#f7fbfb;
  color:var(--s12-ink);font-size:var(--yk-type-body);line-height:var(--yk-line-reading);min-width:0;
}
.s12-root *{box-sizing:border-box}
.s12-root h1,.s12-root h2,.s12-root p{margin:0}
.s12-root a{color:inherit;text-decoration:none}
.s12-root button{font:inherit;cursor:pointer}
.s12-root textarea{font:inherit}
.s12-root :is(a,button,textarea,summary):focus-visible{outline:3px solid var(--s12-teal);outline-offset:2px;border-radius:8px}
.s12-sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

body.s12-focus-body>aside{display:none}
body.s12-focus-body>main{margin-left:0;max-width:none;padding:26px 30px 72px}

.s12-board-title{display:flex;flex-wrap:wrap;align-items:center;gap:10px;min-width:0}
.s12-brand{display:flex;align-items:center;gap:9px}
.s12-brand svg{width:30px;height:27px;fill:currentColor;stroke:none;color:var(--s12-teal)}
.s12-brand b{font-size:24px;font-weight:var(--yk-weight-page);letter-spacing:-.01em}
.s12-title-sep{color:var(--s12-line);font-size:var(--yk-type-control)}
.s12-title-text{font-size:var(--yk-type-control);color:var(--s12-ink)}
.s12-badge{font-size:var(--yk-type-micro);font-weight:var(--yk-weight-title);color:var(--s12-teal);background:#e7f5f3;border:1px solid #c6e7e3;border-radius:999px;padding:4px 10px;white-space:nowrap;line-height:var(--yk-line-ui)}
.s12-lead{color:var(--s12-muted);font-size:var(--yk-type-body);margin-top:10px;line-height:var(--yk-line-reading)}
.s12-foot-note{margin-top:20px;font-size:var(--yk-type-meta);color:var(--s12-muted)}

.s12-board{display:flex;flex-wrap:wrap;gap:22px;justify-content:center;margin-top:20px;min-width:0}
.s12-phone{flex:1 1 285px;max-width:330px;min-width:0}
.s12-bezel{padding:9px;border-radius:32px;background:linear-gradient(160deg,#1b3a45,#0d2229);box-shadow:0 12px 26px rgba(17,40,58,.16)}
.s12-screen{display:flex;flex-direction:column;min-height:620px;background:#fff;border-radius:24px;overflow:hidden}
.s12-status{display:flex;align-items:center;justify-content:space-between;padding:12px 18px 4px;font-size:13px;font-weight:600;color:#26364a}
.s12-status-icons{font-size:var(--yk-type-micro);letter-spacing:1px;color:#5b6c7d}

.s12-app-head{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px;padding:8px 18px 12px;border-bottom:1px solid var(--s12-line);min-width:0}
.s12-app-brand{display:flex;align-items:center;gap:7px}
.s12-app-brand svg{width:22px;height:20px;fill:currentColor;stroke:none;color:var(--s12-teal)}
.s12-app-brand b{font-size:17px;font-weight:var(--yk-weight-page)}
.s12-acct{position:relative;min-width:0}
.s12-acct summary{list-style:none;cursor:pointer;font-size:13px;color:var(--s12-muted);border:1px solid var(--s12-line);border-radius:999px;padding:4px 11px;background:#fff}
.s12-acct summary::-webkit-details-marker{display:none}
.s12-acct summary:hover{background:var(--s12-hover);border-color:var(--s12-teal-2)}
.s12-acct p{font-size:12px;color:var(--s12-muted);background:var(--s12-soft);border:1px solid var(--s12-line);border-radius:10px;padding:8px 10px;margin-top:6px}
.s12-back{font-size:var(--yk-type-meta);color:var(--s12-teal);font-weight:var(--yk-weight-title)}
.s12-back:hover{text-decoration:underline}
.s12-saved{font-size:12px;color:#3f7d6f;background:#e7f5f3;border-radius:999px;padding:3px 10px}
.s12-gear{border:1px solid var(--s12-line);background:#fff;border-radius:9px;padding:5px 12px;font-size:var(--yk-type-meta);color:var(--s12-muted)}
.s12-gear:hover{background:var(--s12-hover);border-color:var(--s12-teal-2)}

.s12-screen-body{flex:1;min-width:0;padding:16px 18px 20px;display:grid;gap:12px;align-content:start}
.s12-h1{font-size:var(--yk-type-page);font-weight:var(--yk-weight-page);line-height:var(--yk-line-heading)}
.s12-h1-meta{font-size:var(--yk-type-meta);color:var(--s12-muted);margin-top:-8px}
.s12-h2{font-size:var(--yk-type-card);font-weight:var(--yk-weight-title);display:flex;flex-wrap:wrap;align-items:center;gap:8px;line-height:var(--yk-line-ui)}
.s12-muted{font-size:var(--yk-type-meta);color:var(--s12-muted)}

.s12-card{display:grid;gap:6px;border:1px solid var(--s12-line);border-radius:12px;padding:13px 14px;background:#fff;min-width:0}
.s12-card:hover{background:var(--s12-hover);border-color:var(--s12-teal-2)}
.s12-card-head{display:flex;align-items:center;justify-content:space-between;gap:8px;min-width:0}
.s12-card-head b{font-size:var(--yk-type-meta);color:var(--s12-teal);font-weight:var(--yk-weight-title)}
.s12-more{font-size:var(--yk-type-meta);color:var(--s12-muted);white-space:nowrap}
.s12-card strong{font-size:16px;font-weight:var(--yk-weight-title)}
.s12-card small{font-size:13px;color:var(--s12-muted)}
.s12-time{font-variant-numeric:tabular-nums}
.s12-bar{display:block;height:6px;border-radius:999px;background:#e8eef1;overflow:hidden}
.s12-bar i{display:block;height:100%;border-radius:999px;background:linear-gradient(90deg,var(--s12-teal),var(--s12-teal-2))}
.s12-bar-big{height:8px;margin-top:-4px}

.s12-player{display:flex;align-items:center;justify-content:space-between;gap:10px;background:#0f2b33;color:#e8f6f4;border-radius:11px;padding:12px 14px;font-size:14px;font-variant-numeric:tabular-nums}
.s12-speed{border:1px solid rgba(255,255,255,.4);border-radius:8px;padding:2px 8px;font-size:12px}
.s12-q{font-size:14px;line-height:1.75;background:var(--s12-soft);border-left:3px solid var(--s12-teal-2);border-radius:0 10px 10px 0;padding:11px 12px;overflow-wrap:anywhere}
.s12-field{position:relative;display:block;min-width:0}
.s12-field textarea{width:100%;min-height:104px;resize:vertical;border:1px solid var(--s12-line);border-radius:11px;padding:12px 14px 30px;line-height:var(--yk-line-reading);color:var(--s12-ink)}
.s12-field textarea::placeholder{color:#526976}
.s12-field textarea:hover{border-color:var(--s12-teal-2)}
.s12-counter{position:absolute;right:12px;bottom:9px;font-size:12px;color:var(--s12-muted);background:#fff;padding:0 2px}
.s12-draft{font-size:12px;color:#3f7d6f}
.s12-primary{width:100%;min-height:44px;border:1px solid var(--s12-teal);border-radius:10px;background:var(--s12-teal);color:#fff;font-size:var(--yk-type-control);font-weight:var(--yk-weight-title);padding:10px 16px}
.s12-primary:hover{background:#0a6a68}
.s12-hint{font-size:12px;color:var(--s12-muted)}
.s12-live{color:var(--s12-teal)}

.s12-recall-top{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px}
.s12-recall-top b{font-size:16px}
.s12-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:-4px}
.s12-tag{font-size:12px;border-radius:999px;padding:3px 10px;white-space:nowrap}
.s12-tag.plain{background:#eef4f6;color:#4d6272}
.s12-tag.teal{background:#e7f5f3;color:var(--s12-teal)}
.s12-tag.amber{background:#fff3e2;color:#96631b}
.s12-body-text{font-size:14px;line-height:1.75;overflow-wrap:anywhere}
.s12-ref{border-top:1px dashed var(--s12-line);padding-top:10px}
.s12-ref summary{display:flex;align-items:center;gap:6px;cursor:pointer;font-size:14px;font-weight:var(--yk-weight-title);color:var(--s12-teal);list-style:none}
.s12-ref summary::-webkit-details-marker{display:none}
.s12-caret{transition:transform .18s}
.s12-ref[open] .s12-caret{transform:rotate(180deg)}
.s12-ref p{font-size:13px;color:var(--s12-muted);background:var(--s12-soft);border:1px solid var(--s12-line);border-radius:10px;padding:10px 12px;margin-top:8px}
.s12-link-card{display:flex;align-items:center;gap:10px}
.s12-link-card span{display:grid;gap:2px;min-width:0}
.s12-link-card b{font-size:14px;font-weight:var(--yk-weight-title)}
.s12-link-card i{margin-left:auto;font-style:normal;color:var(--s12-muted)}

.s12-tabs{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:2px;border-top:1px solid var(--s12-line);padding:8px 6px 10px;background:#fff}
.s12-tabs span{display:flex;flex-direction:column;align-items:center;gap:3px;min-width:0;color:#7a8b9a;font-size:12px}
.s12-tabs svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.s12-tabs span b{font-weight:600}
.s12-tabs span.on{color:var(--s12-teal)}

@media(max-width:1020px){
  .s12-board{gap:18px}
  .s12-phone{flex:1 1 260px}
}
@media(max-width:760px){
  body.s12-focus-body>main{padding:16px 14px 92px}
  .s12-board-title{gap:8px}
  .s12-brand b{font-size:1.3125rem}
  .s12-board{display:grid;grid-template-columns:minmax(0,1fr);gap:16px}
  .s12-phone{max-width:none}
  .s12-bezel{padding:7px;border-radius:28px}
  .s12-screen{min-height:0;border-radius:21px}
  .s12-status{padding:10px 14px 2px}
  .s12-screen-body{padding:14px 14px 18px}
}
@media(max-width:360px){
  .s12-app-head{padding:6px 13px 10px}
  .s12-screen-body{padding:12px 12px 16px}
  .s12-h1{font-size:var(--yk-type-page)}
}