/* 心宝学习：清爽笔记本风，跟随手机深色模式 */
:root {
  --bg: #f6faf9;
  --card: #ffffff;
  --text: #1f2d2b;
  --muted: #6b7f7b;
  --line: #e2ebe9;
  --primary: #3a9e92;
  --primary-soft: #e3f4f1;
  --primary-text: #ffffff;
  --accent: #5b8def;
  --warn-bg: #fff6e0;
  --warn-text: #7a5a00;
  --danger: #d4534b;
  --analogy-bg: #f1f7ff;
  --shadow: 0 1px 3px rgba(30, 60, 55, 0.08), 0 4px 14px rgba(30, 60, 55, 0.05);
  --radius: 14px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14201e;
    --card: #1c2a28;
    --text: #e4eeec;
    --muted: #93a8a4;
    --line: #2c3d3a;
    --primary: #5cc2b5;
    --primary-soft: #21403b;
    --primary-text: #0f1d1b;
    --accent: #8aaef5;
    --warn-bg: #3a3220;
    --warn-text: #f1d58a;
    --danger: #f07c74;
    --analogy-bg: #1f2c3f;
    --shadow: none;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.7 -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  padding-bottom: env(safe-area-inset-bottom);
}
[hidden] { display: none !important; }
button, input, textarea { font: inherit; color: inherit; }
img { max-width: 100%; }

.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 8px;
  height: 52px; padding: 0 12px; padding-top: env(safe-area-inset-top);
  box-sizing: content-box;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 18px; color: var(--text); text-decoration: none; flex: 1; }
.icon-btn { border: 0; background: none; font-size: 30px; line-height: 1; padding: 0 6px 4px; cursor: pointer; color: var(--primary); }
.text-btn { border: 0; background: none; color: var(--primary); font-weight: 600; cursor: pointer; padding: 8px; }

main { max-width: 720px; margin: 0 auto; padding: 16px 16px 48px; }
.muted { color: var(--muted); font-size: 14px; }
.center { text-align: center; }
.error { color: var(--danger); font-size: 14px; }

.btn {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  width: 100%; min-height: 48px; padding: 10px 16px; margin: 10px 0;
  border-radius: 12px; border: 1px solid var(--line); background: var(--card);
  font-weight: 600; cursor: pointer; text-align: center;
  -webkit-tap-highlight-color: transparent;
}
.btn:active { transform: scale(0.99); }
.btn.primary { background: var(--primary); border-color: var(--primary); color: var(--primary-text); }
.btn.ghost { background: transparent; color: var(--primary); border-color: var(--primary); }
.btn.big { min-height: 64px; font-size: 20px; }
.btn:disabled { opacity: 0.5; cursor: default; }
.btn-row { display: flex; gap: 10px; }
.btn-row .btn { margin: 6px 0; }

/* 口令页 */
.login-card { max-width: 360px; margin: 10vh auto 0; text-align: center; }
.login-card h1 { margin: 12px 0 0; font-size: 28px; }
.login-card input {
  width: 100%; min-height: 50px; margin-top: 24px; padding: 0 14px;
  border: 1px solid var(--line); border-radius: 12px; background: var(--card); font-size: 18px; text-align: center;
}

/* 首页 */
.mock-banner { background: var(--warn-bg); color: var(--warn-text); border-radius: 12px; padding: 10px 14px; font-size: 14px; margin: 0 0 8px; }
.section-title { font-size: 15px; color: var(--muted); font-weight: 600; margin: 20px 0 8px; }
.subjects { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.subject {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 16px 8px; border-radius: var(--radius); border: 2px solid var(--line);
  background: var(--card); font-size: 18px; font-weight: 700; cursor: pointer; box-shadow: var(--shadow);
}
.subject-icon { font-size: 28px; line-height: 1.2; }
.subject.active { border-color: var(--primary); background: var(--primary-soft); }
.tip { font-size: 13px; color: var(--muted); margin: 4px 2px; }
.quota { font-size: 13px; color: var(--muted); text-align: center; margin-top: 14px; }

.record-list { list-style: none; padding: 0; margin: 0; }
.record {
  display: flex; align-items: center; gap: 12px; padding: 10px; margin-bottom: 10px;
  background: var(--card); border-radius: 12px; box-shadow: var(--shadow); cursor: pointer;
}
.record img { width: 52px; height: 52px; object-fit: cover; border-radius: 8px; flex: none; border: 1px solid var(--line); }
.record-main { flex: 1; min-width: 0; }
.record-title { font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.record-meta { font-size: 12px; color: var(--muted); }
.record-del { border: 0; background: none; color: var(--muted); font-size: 13px; padding: 8px; cursor: pointer; }

/* 等待页 */
#view-loading { text-align: center; padding-top: 24px; }
.loading-photo { max-height: 40vh; border-radius: 12px; box-shadow: var(--shadow); opacity: 0.85; }
.spinner { width: 40px; height: 40px; margin: 24px auto 8px; border-radius: 50%; border: 4px solid var(--primary-soft); border-top-color: var(--primary); animation: spin 0.9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.spinner.small { width: 20px; height: 20px; border-width: 3px; margin: 0; flex: none; }
.card.writing { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: 14px; }
.loading-text { font-size: 18px; font-weight: 600; margin: 8px 0 0; }

/* 讲解页 */
.result-head { display: flex; gap: 12px; align-items: flex-start; }
.result-thumb { width: 84px; height: 112px; object-fit: cover; border-radius: 10px; flex: none; box-shadow: var(--shadow); cursor: zoom-in; }
.result-title { font-size: 19px; margin: 0 0 4px; line-height: 1.4; }
.badge { display: inline-block; font-size: 12px; padding: 1px 8px; border-radius: 99px; background: var(--primary-soft); color: var(--primary); margin-right: 4px; }
.badge.warn { background: var(--warn-bg); color: var(--warn-text); }
.card { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 14px 16px; margin: 14px 0; overflow: hidden; }
.card h3 { margin: 0 0 6px; font-size: 17px; }
.card.summary { border-left: 4px solid var(--primary); }
.card.unclear { background: var(--warn-bg); color: var(--warn-text); }
.card.unclear h3 { color: inherit; }
.point-no { color: var(--primary); margin-right: 4px; }
.analogy { background: var(--analogy-bg); border-radius: 10px; padding: 8px 12px; margin-top: 10px; font-size: 15px; }
.analogy::before { content: "💡 打个比方："; font-weight: 700; color: var(--accent); }
.rich p { margin: 6px 0; }
.rich ul, .rich ol, .card ul { padding-left: 1.3em; margin: 6px 0; }
.rich .katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; margin: 8px 0; }
.rich .katex { font-size: 1.05em; }
.rich .katex-display > .katex { font-size: 1em; } /* 手机屏窄，单独一行的长方程式稍微缩小，太长时可以左右滑动 */
.mindmap { width: 100%; height: 380px; display: block; }
.mindmap-wrap { position: relative; margin: 0 -16px -14px; border-top: 1px solid var(--line); }
.mindmap-fit { position: absolute; right: 8px; top: 8px; font-size: 12px; padding: 4px 10px; border-radius: 99px; border: 1px solid var(--line); background: var(--card); cursor: pointer; z-index: 1; }
/* 选择器写重一点，压过 markmap 自带的样式，深色模式下文字才看得清 */
.mindmap-wrap svg.markmap { color: var(--text); --markmap-text-color: var(--text); --markmap-circle-open-bg: var(--card); --markmap-font: 400 14px/20px -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; }
.structures { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 10px; }
.structure { text-align: center; font-size: 14px; }
.structure svg { width: 100%; height: 140px; background: #fff; border-radius: 10px; border: 1px solid var(--line); }
.drawn img { width: 100%; border-radius: 10px; margin-top: 8px; }
.chat-item { margin: 10px 0; }
.chat-q { font-weight: 600; }
.chat-q::before { content: "问："; color: var(--primary); }
.chat-a { background: var(--primary-soft); border-radius: 10px; padding: 8px 12px; margin-top: 4px; }
.ask-form { display: flex; gap: 8px; margin-top: 10px; }
.ask-form textarea { flex: 1; min-height: 48px; max-height: 140px; padding: 10px 12px; border-radius: 12px; border: 1px solid var(--line); background: var(--bg); resize: vertical; }
.ask-form .btn { width: auto; margin: 0; flex: none; }
.small-note { font-size: 12px; color: var(--muted); margin-top: 6px; }
.fail-card { text-align: center; padding: 24px 16px; }
.fail-card .big-emoji { font-size: 44px; }

/* 历史页 */
.tabs { display: grid; grid-template-columns: 1fr 1fr; background: var(--card); border-radius: 12px; padding: 4px; margin-bottom: 14px; box-shadow: var(--shadow); }
.tab { border: 0; background: none; padding: 10px; border-radius: 9px; font-weight: 600; color: var(--muted); cursor: pointer; }
.tab.active { background: var(--primary); color: var(--primary-text); }

/* 看大图 */
.viewer { position: fixed; inset: 0; z-index: 50; background: rgba(0, 0, 0, 0.92); display: flex; flex-direction: column; }
.viewer-scroll { flex: 1; overflow: auto; display: flex; align-items: center; justify-content: center; touch-action: pinch-zoom pan-x pan-y; }
.viewer-scroll img { max-width: none; width: 100%; height: auto; }
.viewer-tip { color: #bbb; text-align: center; font-size: 13px; margin: 6px 0 0; }
.viewer-close { width: auto; margin: 10px auto calc(16px + env(safe-area-inset-bottom)); padding: 8px 40px; }

.toast {
  position: fixed; left: 50%; bottom: calc(24px + env(safe-area-inset-bottom)); transform: translateX(-50%);
  max-width: calc(100% - 32px); background: #263532; color: #fff; padding: 10px 16px; border-radius: 12px; font-size: 14px; z-index: 60;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
}