/* ══════════════════════════════════════════════════════════
   v3.5 · 教学中心（screen-learn）
   与首页共用「墨玉」设计语言：深墨玉基底 / 琥珀金主行动
   ══════════════════════════════════════════════════════════ */

.learn {
  position: absolute;
  inset: 0;
  overflow-y: auto;
  overflow-x: hidden;
  background:
    radial-gradient(1100px 540px at 82% -140px, rgba(166, 124, 61, .12), transparent 62%),
    radial-gradient(900px 480px at 4% 4%, rgba(74, 124, 89, .06), transparent 58%),
    #FAFAF7;
  color: #1C1C1A;
  font-size: 14px;
  scroll-behavior: smooth;
}
.learn ::selection { background: rgba(166, 124, 61, .32); }

/* ── Hero ── */
.learn-hero { padding: 34px 0 26px; border-bottom: 1px solid rgba(28, 28, 26, .07); }
.learn-hero-top { display: flex; align-items: center; gap: 14px; margin-bottom: 22px; }
.learn-ver { font-size: 11px; color: var(--ink-3); border: 1px solid rgba(28, 28, 26, .12); border-radius: 999px; padding: 3px 10px; }
.learn-hero h1 { font-size: 32px; font-weight: 760; letter-spacing: .3px; margin: 0 0 12px; }
.learn-hero .grad { background: linear-gradient(100deg, #B98F4E, #A67C3D 45%, #9C7430); -webkit-background-clip: text; background-clip: text; color: transparent; margin-left: 10px; font-size: 22px; }
.learn-hero-sub { font-size: 13.5px; color: #9aa69e; line-height: 1.9; max-width: 860px; margin: 0 0 18px; }
.learn-hero-sub b { color: #e9d9b3; font-weight: 640; }
.learn-progress-row { margin-bottom: 22px; }
.learn-progress { display: flex; align-items: center; gap: 12px; max-width: 460px; font-size: 12px; color: var(--ink-3); }
.lp-bar { flex: 1; height: 6px; border-radius: 6px; background: rgba(28, 28, 26, .09); overflow: hidden; }
.lp-bar-f { height: 100%; border-radius: 6px; background: linear-gradient(90deg, #B98F4E, #9C7430); transition: width .4s; }

/* 学习路径 */
.learn-tracks { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.ltrk {
  display: flex; align-items: flex-start; gap: 14px;
  border: 1px solid rgba(28, 28, 26, .09); border-radius: 16px;
  background: linear-gradient(170deg, #FFFFFF, #F7F6F2);
  padding: 18px 18px 16px;
  transition: border-color .2s, transform .2s;
}
.ltrk:hover { border-color: rgba(166, 124, 61, .4); transform: translateY(-3px); }
.ltrk.full { border-color: rgba(74, 124, 89, .4); }
.ltrk-no { font-size: 22px; font-weight: 780; color: rgba(166, 124, 61, .5); line-height: 1; padding-top: 2px; }
.ltrk.full .ltrk-no { color: #4A7C59; }
.ltrk-main { flex: 1; min-width: 0; }
.ltrk-t { font-size: 14px; font-weight: 680; color: #f0f5f1; margin-bottom: 5px; }
.ltrk-d { font-size: 11.5px; color: #6B6A66; line-height: 1.65; margin-bottom: 12px; }
.ltrk-bar { height: 4px; border-radius: 4px; background: rgba(28, 28, 26, .09); overflow: hidden; }
.ltrk-bar-f { height: 100%; background: linear-gradient(90deg, #B98F4E, #9C7430); transition: width .4s; }
.ltrk.full .ltrk-bar-f { background: #4A7C59; }

/* ── 主体两栏 ── */
.learn-main { display: grid; grid-template-columns: 292px 1fr; gap: 26px; align-items: start; padding: 28px 0 10px; }

/* 目录 */
.learn-toc {
  position: sticky; top: 18px;
  max-height: calc(100vh - 36px); overflow-y: auto;
  border: 1px solid rgba(28, 28, 26, .08); border-radius: 16px;
  background: rgba(255, 255, 255, .92); padding: 14px;
}
.learn-toc::-webkit-scrollbar-thumb { background: rgba(28, 28, 26, .14); border: 3px solid transparent; background-clip: content-box; border-radius: 8px; }
.toc-search { position: relative; margin-bottom: 10px; }
.toc-search input {
  width: 100%; box-sizing: border-box;
  background: rgba(28, 28, 26, .05); border: 1px solid rgba(28, 28, 26, .1);
  color: #1C1C1A; border-radius: 10px; padding: 9px 30px 9px 12px; font-size: 12.5px; outline: none;
}
.toc-search input:focus { border-color: rgba(166, 124, 61, .5); }
.toc-search svg { position: absolute; right: 10px; top: 50%; transform: translateY(-50%); color: var(--ink-3); pointer-events: none; }
.toc-ch { margin-bottom: 4px; }
.toc-chap {
  width: 100%; display: flex; align-items: center; gap: 9px;
  padding: 9px 8px; border-radius: 10px; color: var(--ink); font-size: 13px; font-weight: 650;
  cursor: pointer; text-align: left;
}
.toc-chap:hover { background: rgba(28, 28, 26, .05); }
.toc-chap svg { margin-left: auto; transition: transform .18s; color: var(--ink-3); flex: none; }
.toc-ch.open .toc-chap svg { transform: rotate(90deg); }
.toc-no {
  font-size: 10px; font-weight: 760; color: #A67C3D;
  background: rgba(166, 124, 61, .12); border: 1px solid rgba(166, 124, 61, .28);
  border-radius: 6px; padding: 2px 5px; flex: none; letter-spacing: .04em;
}
.toc-t { flex: 1; min-width: 0; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.toc-n { font-size: 10.5px; color: var(--ink-3); flex: none; }
.toc-les {
  width: 100%; display: flex; align-items: center; gap: 8px;
  padding: 7px 8px 7px 14px; border-radius: 9px; color: var(--ink-3); font-size: 12.5px;
  cursor: pointer; text-align: left; border-left: 2px solid transparent;
}
.toc-les:hover { background: rgba(28, 28, 26, .04); color: #1C1C1A; }
.toc-les.on { background: rgba(166, 124, 61, .1); color: #f0cd8a; border-left-color: #A67C3D; }
.toc-les.done .toc-lt { color: #6f7b73; text-decoration: line-through; text-decoration-color: rgba(74, 124, 89, .5); }
.toc-les.on.done .toc-lt { color: #8fae9d; }
.toc-dot {
  width: 15px; height: 15px; border-radius: 50%; flex: none;
  border: 1px solid rgba(28, 28, 26, .22);
  display: grid; place-items: center; color: #FFFDF8;
}
.toc-les.done .toc-dot { background: #4A7C59; border-color: #4A7C59; }
.toc-lt { flex: 1; min-width: 0; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.toc-mins { font-size: 10.5px; color: #6f7b73; flex: none; font-variant-numeric: tabular-nums; }

/* 正文 */
.learn-body { min-width: 0; }
.lesson {
  border: 1px solid rgba(28, 28, 26, .09); border-radius: 18px;
  background: linear-gradient(170deg, #FFFFFF, #F7F6F2);
  padding: 26px 28px 22px;
  animation: lesson-in .22s ease;
}
@keyframes lesson-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
.lesson-crumb { font-size: 11px; letter-spacing: .1em; color: #A67C3D; margin-bottom: 10px; }
.lesson-title-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }
.lesson-title { font-size: 21px; font-weight: 720; margin: 0; color: #f2f7f3; }
.lesson-mins { display: inline-flex; align-items: center; gap: 5px; font-size: 11.5px; color: var(--ink-3); }
.lesson-goal { font-size: 13px; color: var(--ink-3); line-height: 1.8; margin: 0 0 18px; background: rgba(28, 28, 26, .04); border-left: 3px solid #A67C3D; border-radius: 0 10px 10px 0; padding: 10px 14px; }
.lesson-goal b { color: #e9d9b3; }

.lesson-steps { list-style: none; margin: 0 0 20px; padding: 0; display: flex; flex-direction: column; gap: 14px; }
.lstep { display: flex; gap: 13px; }
.lstep-no {
  width: 26px; height: 26px; border-radius: 9px; flex: none; margin-top: 1px;
  background: rgba(166, 124, 61, .14); border: 1px solid rgba(166, 124, 61, .32);
  color: #f0cd8a; font-size: 12px; font-weight: 720;
  display: grid; place-items: center;
}
.lstep-main { flex: 1; min-width: 0; }
.lstep-t { font-size: 13.5px; font-weight: 680; color: #1C1C1A; margin-bottom: 4px; }
.lstep-d { font-size: 12.5px; color: #9aa69e; line-height: 1.85; white-space: pre-line; }
.lstep-tip {
  display: flex; gap: 7px; align-items: flex-start;
  margin-top: 7px; font-size: 11.5px; color: #8fae9d;
  background: rgba(74, 124, 89, .08); border: 1px solid rgba(74, 124, 89, .2);
  border-radius: 9px; padding: 7px 10px; line-height: 1.7;
}
.lstep-tip svg { margin-top: 2px; flex: none; }

.lesson-copy { margin-bottom: 20px; }
.lcopy-head { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.lcopy-label { font-size: 12px; color: #e9d9b3; font-weight: 640; }
.lcopy-ta {
  width: 100%; box-sizing: border-box; resize: vertical; min-height: 88px;
  background: rgba(28, 28, 26, .05); color: var(--ink-2);
  border: 1px solid rgba(28, 28, 26, .12); border-radius: 12px;
  padding: 12px 14px; font-size: 12.5px; line-height: 1.8; outline: none;
  font-family: inherit;
}
.lcopy-ta:focus { border-color: rgba(166, 124, 61, .45); }

.lesson-params { margin-bottom: 20px; }
.lp-title { font-size: 12px; font-weight: 680; color: #e9d9b3; margin-bottom: 9px; }
.lp-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 9px; }
.lp-item { background: rgba(28, 28, 26, .04); border: 1px solid rgba(28, 28, 26, .09); border-radius: 11px; padding: 10px 12px; }
.lp-item b { display: block; font-size: 11.5px; color: var(--ink); margin-bottom: 3px; }
.lp-item span { font-size: 11.5px; color: #6B6A66; line-height: 1.7; }

.lesson-pit { margin-bottom: 20px; background: rgba(220, 88, 68, .07); border: 1px solid rgba(220, 88, 68, .22); border-radius: 12px; padding: 12px 14px; }
.lpit-title { display: flex; align-items: center; gap: 7px; font-size: 12px; font-weight: 680; color: #e8a08f; margin-bottom: 7px; }
.lesson-pit ul { margin: 0; padding-left: 18px; }
.lesson-pit li { font-size: 12px; color: #b3a49b; line-height: 1.85; }

.lesson-accept {
  display: flex; gap: 8px; align-items: flex-start;
  font-size: 12px; color: #8fae9d; line-height: 1.75;
  background: rgba(74, 124, 89, .07); border: 1px dashed rgba(74, 124, 89, .3);
  border-radius: 11px; padding: 10px 13px; margin-bottom: 20px;
}
.lesson-accept svg { margin-top: 2px; flex: none; }
.lesson-accept b { color: #a9e3c4; }

.lesson-ops { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; border-top: 1px solid rgba(28, 28, 26, .08); padding-top: 16px; }

/* 同章其他课程 */
.lesson-next { margin-top: 18px; }
.ln-title { font-size: 12px; color: var(--ink-3); margin-bottom: 9px; }
.ln-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 9px; }
.ln-item {
  display: flex; align-items: center; gap: 8px;
  background: rgba(28, 28, 26, .035); border: 1px solid rgba(28, 28, 26, .08);
  border-radius: 11px; padding: 10px 12px; color: var(--ink-3); font-size: 12.5px;
  cursor: pointer; text-align: left; transition: border-color .18s, color .18s;
}
.ln-item:hover { border-color: rgba(166, 124, 61, .4); color: #1C1C1A; }
.ln-item svg:last-child { margin-left: auto; color: #6f7b73; flex: none; }
.ln-item > span:nth-child(2) { flex: 1; min-width: 0; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; text-align: left; }

/* 页脚说明 */
.learn-foot {
  margin: 26px 0 40px; border-top: 1px solid rgba(28, 28, 26, .07); padding-top: 22px;
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
}
.lf-t { font-size: 14px; font-weight: 680; color: var(--ink); }
.lf-d { flex: 1; min-width: 240px; font-size: 12px; color: var(--ink-3); line-height: 1.75; }

@media (max-width: 980px) {
  .learn-main { grid-template-columns: 1fr; }
  .learn-toc { position: static; max-height: none; }
  .learn-tracks { grid-template-columns: 1fr; }
  .learn-hero h1 { font-size: 25px; }
  .learn-hero .grad { font-size: 18px; margin-left: 6px; }
}