/* 家庭学习工具箱 - 平板优先样式 */
:root {
  --bg: #f4f6fb;
  --panel: #ffffff;
  --text: #212529;
  --sub: #6b7280;
  --line: #e5e9f2;
  --primary: #4f6ef7;
  --radius: 14px;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}

/* ===== 顶部 ===== */
.topbar {
  position: sticky; top: 0; z-index: 20;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  padding: 12px 20px 8px;
}
.topbar .row1 { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.title { font-size: 22px; font-weight: 700; margin: 0; white-space: nowrap; }
.title small { font-weight: 400; color: var(--sub); font-size: 14px; margin-left: 8px; }
.search {
  flex: 1; min-width: 220px; max-width: 520px;
  display: flex; align-items: center; gap: 8px;
  background: #eef1f8; border-radius: 12px; padding: 10px 14px;
}
.search input {
  border: 0; outline: 0; background: transparent; flex: 1;
  font-size: 17px; color: var(--text);
}
.search .ico { color: var(--sub); font-size: 17px; }

/* 筛选 chips */
.filters { display: flex; gap: 8px; overflow-x: auto; padding: 10px 0 4px; scrollbar-width: none; }
.filters::-webkit-scrollbar { display: none; }
.chip {
  flex: 0 0 auto; border: 1px solid var(--line); background: #fff;
  color: var(--text); border-radius: 999px; padding: 8px 16px;
  font-size: 15px; cursor: pointer; transition: all .15s;
}
.chip:hover { border-color: var(--primary); color: var(--primary); }
.chip.active { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }
.chip .n { opacity: .65; font-size: 12px; margin-left: 4px; }

.filterline { display: flex; align-items: center; gap: 10px; }
.filterline .lbl { color: var(--sub); font-size: 14px; flex: 0 0 auto; }

/* ===== 卡片网格 ===== */
main { padding: 16px 20px 60px; }
.count { color: var(--sub); font-size: 14px; margin: 4px 2px 12px; }
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(185px, 1fr));
  gap: 14px;
}
.card {
  position: relative; display: block;
  background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 16px 14px 14px;
  text-decoration: none; color: inherit;
  box-shadow: 0 1px 2px rgba(16, 24, 40, .04);
  transition: transform .12s, box-shadow .12s, border-color .12s;
  min-height: 96px;
}
.card:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(16,24,40,.10); border-color: #cdd6f0; }
.card:active { transform: scale(.98); }
.card .head { display: flex; gap: 11px; align-items: center; }
.card .ic {
  flex: 0 0 auto; width: 42px; height: 42px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  color: #fff; box-shadow: 0 2px 6px rgba(16,24,40,.14);
}
.card .ic svg { width: 23px; height: 23px; }
.card .ic img { width: 100%; height: 100%; object-fit: cover; border-radius: 12px; display: block; }
.card .name {
  flex: 1; font-size: 17px; font-weight: 600; line-height: 1.35;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
  padding-right: 20px;
}
.card .online-btn {
  position: absolute; top: 9px; right: 9px; z-index: 2;
  width: 27px; height: 27px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  color: var(--sub); background: #f1f3f9; font-size: 15px;
  cursor: pointer; transition: all .15s;
}
.card .online-btn:hover { background: var(--primary); color: #fff; }
.card .meta { margin-top: 10px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.badge {
  font-size: 12px; padding: 2px 9px; border-radius: 999px;
  color: #fff; font-weight: 600;
}
.grade-tag { font-size: 12px; color: var(--sub); background: #f1f3f9; border-radius: 999px; padding: 2px 9px; }
.card .bar {
  position: absolute; left: 0; top: 14px; bottom: 14px; width: 4px; border-radius: 4px;
}

/* 学科色 */
.s-数学   { background: #4f6ef7; }
.s-语文   { background: #e8590c; }
.s-英语   { background: #12b886; }
.s-物理   { background: #7048e8; }
.s-化学   { background: #f03e3e; }
.s-生物科学 { background: #2f9e44; }
.s-地理历史 { background: #b8860b; }
.s-音乐   { background: #e64980; }
.s-美术手工 { background: #fa5252; }
.s-心理素养 { background: #7950f2; }
.s-教师工具 { background: #1098ad; }
.s-游戏   { background: #f59f00; }
.s-综合工具 { background: #868e96; }

.empty { text-align: center; color: var(--sub); padding: 80px 0; font-size: 17px; }

/* file:// 提示 */
.filehint {
  display: none; background: #fff8e1; border: 1px solid #ffe08a; color: #8a6d1a;
  border-radius: 12px; padding: 12px 16px; margin: 12px 2px 0; font-size: 15px;
}
body.is-file .filehint { display: block; }

/* ===== 窄屏 ===== */
@media (max-width: 640px) {
  .grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 10px; }
  .card { min-height: 88px; padding: 13px 12px 12px; }
  .card .name { font-size: 15px; }
  .title { font-size: 19px; }
  main { padding: 12px 12px 40px; }
  .topbar { padding: 10px 12px 6px; }
}

/* ===== viewer ===== */
body.viewer { display: flex; flex-direction: column; height: 100vh; overflow: hidden; }
.v-bar {
  flex: 0 0 auto; display: flex; align-items: center; gap: 10px;
  background: #fff; border-bottom: 1px solid var(--line);
  padding: 8px 12px; min-height: 56px;
}
.v-btn {
  border: 1px solid var(--line); background: #fff; border-radius: 10px;
  padding: 9px 14px; font-size: 15px; cursor: pointer; color: var(--text);
  white-space: nowrap;
}
.v-btn:hover { border-color: var(--primary); color: var(--primary); }
.v-btn.mode-on { background: var(--primary); border-color: var(--primary); color: #fff; }
.v-btn.mode-on:hover { color: #fff; opacity: .92; }
.v-btn:disabled { opacity: .45; cursor: not-allowed; border-color: var(--line); color: var(--sub); }
.v-name { flex: 1; font-weight: 600; font-size: 17px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
iframe.tool { flex: 1; width: 100%; border: 0; background: #fff; }