:root {
  --bg: #f5f6fa;
  --panel: #ffffff;
  --border: #e4e7ee;
  --text: #23272f;
  --muted: #8a92a3;
  --primary: #4f6ef7;
  --primary-dark: #3b57d8;
  --red: #e5484d;
  --orange: #f5a623;
  --green: #2fb380;
  --blue: #3e9cf0;
  --shadow: 0 2px 10px rgba(30, 40, 70, 0.07);
  --radius: 12px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

/* 强制 hidden 属性生效，覆盖任何 display: flex/grid 规则 */
[hidden] { display: none !important; }

body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  overflow: hidden;
}

.layout { display: flex; height: 100vh; }

/* ---------- 侧边栏 ---------- */
.sidebar {
  width: 230px;
  background: var(--panel);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 18px 14px;
  gap: 14px;
}

.logo { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 17px; padding: 0 6px; }
.logo-icon { font-size: 22px; }

.deck-nav { flex: 1; overflow-y: auto; display: flex; flex-direction: column; gap: 4px; }

.deck-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 10px; border-radius: 8px; cursor: pointer;
  font-size: 14px; color: #444c5c; border: none; background: none; text-align: left; width: 100%;
}
.deck-item:hover { background: #f0f2f8; }
.deck-item.active { background: #eaeeff; color: var(--primary); font-weight: 600; }
.deck-item .count {
  font-size: 12px; color: var(--muted); background: #eef1f6; border-radius: 10px; padding: 1px 7px;
}
.deck-item.active .count { background: #dce4ff; color: var(--primary); }

.btn-newdeck {
  border: 1px dashed #c4ccdd; background: none; border-radius: 8px;
  padding: 8px; color: var(--muted); cursor: pointer; font-size: 13px;
}
.btn-newdeck:hover { color: var(--primary); border-color: var(--primary); }

.sidebar-actions { display: flex; gap: 8px; }
.sidebar-actions .wide { flex: 1; }
.form-label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.remember-row {
  display: flex; align-items: center; gap: 8px;
  font-size: 13px; color: var(--muted); cursor: pointer;
  margin: 10px 0 2px; user-select: none;
}
.remember-row input { width: 15px; height: 15px; cursor: pointer; accent-color: var(--primary); }

/* ---------- 主区域 ---------- */
.main { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

.topbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 28px; background: var(--panel); border-bottom: 1px solid var(--border);
}
.topbar-left { display: flex; align-items: center; gap: 12px; }
.topbar h1 { font-size: 19px; font-weight: 700; }

.tabs { display: flex; gap: 4px; background: #eef1f6; padding: 4px; border-radius: 10px; }
.tab { border: none; background: none; padding: 7px 20px; border-radius: 8px; cursor: pointer; font-size: 14px; color: var(--muted); }
.tab.active { background: var(--panel); color: var(--text); font-weight: 600; box-shadow: var(--shadow); }

.guest-bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px;
  padding: 10px 28px;
  background: #fff8e6;
  border-bottom: 1px solid #f5e0b3;
  color: #7a5d24;
  font-size: 13.5px;
}
.guest-bar-text { flex: 1; }
.guest-bar .btn { padding: 6px 14px; font-size: 13px; }

.view { flex: 1; overflow-y: auto; padding: 24px 28px; }

/* ---------- 学习视图 ---------- */
.study-meta { display: flex; gap: 10px; margin-bottom: 16px; }
.pill { font-size: 12px; padding: 4px 12px; border-radius: 20px; background: #eef1f6; color: var(--muted); }
.pill b { color: var(--text); }
.pill.red { background: #fdeaea; color: var(--red); }
.pill.green { background: #e5f7f0; color: var(--green); }
.pill.blue { background: #e8f2fd; color: var(--blue); }

.card-stage { display: flex; flex-direction: column; align-items: center; gap: 22px; }

.flashcard {
  width: 100%; max-width: 640px; min-height: 300px;
  background: var(--panel); border: 1px solid var(--border); border-radius: 16px;
  box-shadow: var(--shadow); padding: 36px 40px;
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  white-space: pre-wrap; word-break: break-word;
}
.flashcard-state { font-size: 12px; color: var(--muted); margin-bottom: 18px; letter-spacing: 1px; }
.flashcard-front { font-size: 24px; font-weight: 600; text-align: center; line-height: 1.6; }
.flashcard-divider { width: 100%; display: flex; align-items: center; gap: 12px; margin: 24px 0; color: var(--muted); font-size: 12px; }
.flashcard-divider::before, .flashcard-divider::after { content: ""; flex: 1; height: 1px; background: var(--border); }
.flashcard-back { font-size: 20px; text-align: center; line-height: 1.7; color: #333a47; }

.study-controls { display: flex; flex-direction: column; align-items: center; gap: 18px; width: 100%; max-width: 640px; }

.grade-buttons { display: flex; gap: 10px; width: 100%; }
.grade {
  flex: 1; border: none; border-radius: 10px; padding: 12px 8px; cursor: pointer;
  display: flex; flex-direction: column; align-items: center; gap: 4px; color: #fff;
  transition: transform 0.08s;
}
.grade:hover { transform: translateY(-2px); }
.grade b { font-size: 15px; }
.grade i { font-style: normal; font-size: 12px; opacity: 0.9; }
.grade.again { background: var(--red); }
.grade.hard { background: var(--orange); }
.grade.good { background: var(--green); }
.grade.easy { background: var(--blue); }

.empty-state { text-align: center; padding: 80px 0; font-size: 16px; }
.empty-icon { font-size: 52px; margin-bottom: 14px; }
.muted { color: var(--muted); font-size: 13px; margin-top: 6px; }

/* ---------- 按钮 ---------- */
.btn { border: none; border-radius: 8px; padding: 9px 18px; cursor: pointer; font-size: 14px; }
.btn.primary { background: var(--primary); color: #fff; }
.btn.primary:hover { background: var(--primary-dark); }
.btn.ghost { background: #eef1f6; color: #4a5568; }
.btn.ghost:hover { background: #e2e7f0; }
.btn.big { padding: 12px 40px; font-size: 15px; font-weight: 600; }
.btn.small { padding: 6px 10px; font-size: 12px; }
.btn.danger { color: var(--red); background: #fdeaea; }
.btn.danger:hover { background: #f9d7d8; }

/* ---------- 面板 / 表格 ---------- */
.panel {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 18px 20px; margin-bottom: 18px;
}
.panel h3 { font-size: 15px; margin-bottom: 14px; }
.panel-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 14px; }
.panel-head h3 { margin-bottom: 0; }

.card-form .form-row { display: flex; gap: 10px; }
.card-form input {
  flex: 1; border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; font-size: 14px; outline: none;
}
.card-form input:focus { border-color: var(--primary); }

.card-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.card-table th {
  text-align: left; padding: 8px 10px; color: var(--muted); font-weight: 500;
  border-bottom: 1px solid var(--border); font-size: 12px;
}
.card-table td { padding: 10px; border-bottom: 1px solid #f0f2f6; vertical-align: top; }
.card-table tr:hover td { background: #fafbfd; }
.card-table .td-front { font-weight: 600; max-width: 280px; }
.card-table .td-back { color: #5a6374; max-width: 280px; }
.card-table .ops { display: flex; gap: 6px; }

.state-tag { font-size: 12px; padding: 2px 8px; border-radius: 10px; }
.state-tag.new { background: #eef1f6; color: var(--muted); }
.state-tag.learning { background: #fdf3e2; color: #b97d0e; }
.state-tag.review { background: #e5f7f0; color: var(--green); }
.state-tag.relearning { background: #fdeaea; color: var(--red); }

/* ---------- 统计 ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; margin-bottom: 18px; }
.stat-card {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 16px 18px;
}
.stat-card .num { font-size: 28px; font-weight: 700; margin-bottom: 4px; }
.stat-card .label { font-size: 13px; color: var(--muted); }
.stat-card.red .num { color: var(--red); }
.stat-card.green .num { color: var(--green); }
.stat-card.blue .num { color: var(--blue); }
.stat-card.orange .num { color: var(--orange); }

.forecast { display: flex; align-items: flex-end; gap: 14px; height: 180px; padding-top: 10px; }
.forecast .fcol { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 6px; height: 100%; justify-content: flex-end; }
.forecast .fbar { width: 70%; max-width: 46px; background: linear-gradient(180deg, #6c8bff, var(--primary)); border-radius: 6px 6px 0 0; min-height: 2px; }
.forecast .fnum { font-size: 12px; color: var(--text); font-weight: 600; }
.forecast .flabel { font-size: 12px; color: var(--muted); }

/* ---------- 弹窗 / 提示 ---------- */
.modal-mask {
  position: fixed; inset: 0; background: rgba(20, 26, 40, 0.45);
  display: flex; align-items: center; justify-content: center; z-index: 100;
}
.modal {
  background: var(--panel); border-radius: 14px; padding: 24px;
  width: 420px; max-width: 92vw; box-shadow: 0 10px 40px rgba(0,0,0,0.2);
}
.modal h3 { margin-bottom: 16px; font-size: 16px; }
/* 学习设置 → 数据管理 二级菜单 */
.settings-submenu {
  border: 1px solid var(--border); border-radius: 10px; margin-bottom: 16px; overflow: hidden;
}
.submenu-toggle {
  width: 100%; display: flex; align-items: center; justify-content: space-between;
  background: none; border: none; padding: 10px 12px; cursor: pointer;
  font-size: 13.5px; font-weight: 600; color: var(--text); text-align: left;
}
.submenu-toggle:hover { background: #f2f4fa; }
.submenu-toggle .chev { color: var(--muted); transition: transform .18s ease; font-size: 16px; line-height: 1; }
.submenu-toggle.open .chev { transform: rotate(90deg); color: var(--primary); }
.submenu-body { padding: 4px 12px 12px; border-top: 1px dashed var(--border); }
.submenu-btns { display: flex; gap: 8px; margin-top: 8px; }
.submenu-btns .btn { flex: 1; }
.modal textarea, .modal input {
  width: 100%; border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; font-size: 14px; outline: none; margin-bottom: 12px;
  font-family: inherit;
}
.modal textarea { min-height: 90px; resize: vertical; }
.modal textarea:focus, .modal input:focus { border-color: var(--primary); }
.modal .modal-ops { display: flex; justify-content: flex-end; gap: 10px; }

.confirm-warn { background: #fff8f5; border: 1px solid #fbd9c9; border-radius: 10px; padding: 14px 16px; margin-bottom: 18px; }
.confirm-warn p { font-size: 14px; color: #444c5c; line-height: 1.6; }
.confirm-warn .confirm-sub { margin-top: 6px; font-size: 13px; color: var(--muted); }
.confirm-warn b { color: #c03b2b; }
.confirm-warn em { color: var(--red); font-style: normal; font-weight: 600; }

.toast {
  position: fixed; top: 20px; left: 50%; transform: translateX(-50%);
  background: #2b3245; color: #fff; border-radius: 8px; padding: 10px 22px;
  font-size: 14px; z-index: 200; box-shadow: 0 6px 20px rgba(0,0,0,0.25);
}
.toast.error { background: var(--red); }

/* ---------- MathJax 公式 ---------- */
.mjx-container { vertical-align: middle; }
.flashcard-front, .flashcard-back { line-height: 1.7; }
.flashcard-front .mjx-container, .flashcard-back .mjx-container { margin: 4px 0; }
.card-table .td-front, .card-table .td-back { max-width: 320px; }
.card-table .math-cell { display: block; word-break: break-word; }
.card-table .math-cell .mjx-container { display: inline-block; max-width: 100%; }

/* ---------- 右键菜单 ---------- */
.ctx-menu {
  position: fixed; z-index: 1000; min-width: 160px;
  background: var(--panel); border: 1px solid var(--border); border-radius: 10px;
  box-shadow: 0 8px 28px rgba(35, 39, 47, .14); padding: 5px; user-select: none;
}
.ctx-menu-title {
  padding: 6px 10px; font-size: 12px; color: var(--muted);
  border-bottom: 1px solid var(--border); margin-bottom: 4px;
  max-width: 240px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.ctx-item {
  display: block; width: 100%; text-align: left; padding: 8px 10px;
  border: none; background: none; border-radius: 6px; cursor: pointer;
  font-size: 13px; color: var(--text);
}
.ctx-item:hover { background: #f0f2f8; }
.ctx-item.danger { color: var(--red); }
.ctx-item.danger:hover { background: #fdeaea; }

/* ---------- 用户认证 ---------- */
.topbar-left { display: flex; align-items: center; gap: 16px; min-width: 0; }
.topbar-left h1 { flex-shrink: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.auth-zone { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.guest-badge {
  font-size: 12px; color: var(--muted); background: #f1f3f9;
  padding: 3px 10px; border-radius: 20px; white-space: nowrap;
}
.user-badge {
  font-size: 12px; color: var(--primary); background: #e8eeff;
  padding: 3px 10px; border-radius: 20px; white-space: nowrap; font-weight: 600;
}
.auth-tabs { display: flex; gap: 8px; margin-bottom: 14px; }
.auth-tab {
  flex: 1; padding: 8px 0; border: 1px solid var(--border); border-radius: 8px;
  background: none; cursor: pointer; font-size: 14px; color: var(--muted);
}
.auth-tab.active { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }

/* ---------- 第三方 OAuth 登录 ---------- */
.oauth-divider {
  display: flex; align-items: center; gap: 12px;
  margin: 18px 0 14px; color: var(--muted); font-size: 12px;
}
.oauth-divider::before, .oauth-divider::after {
  content: ""; flex: 1; height: 1px; background: var(--border);
}
.oauth-btns { display: flex; flex-direction: column; gap: 10px; }
.oauth-btn {
  display: flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 14px; border-radius: 10px; border: 1px solid var(--border);
  font-size: 14px; font-weight: 600; cursor: pointer; color: var(--text);
  background: #fff; transition: all .15s;
}
.oauth-btn:hover { transform: translateY(-1px); box-shadow: 0 3px 10px rgba(0,0,0,.08); }
.oauth-ico {
  display: inline-flex; align-items: center; justify-content: center;
  width: 20px; height: 20px; border-radius: 4px; font-size: 14px; color: #fff;
}
.oauth-wechat { border-color: #09bb07; color: #09bb07; }
.oauth-wechat .oauth-ico { background: #09bb07; }
.oauth-google { border-color: #4285f4; color: #4285f4; }
.oauth-google .oauth-ico { background: #4285f4; font-style: italic; font-family: Georgia, serif; }
.oauth-microsoft { border-color: #0067b8; color: #0067b8; }
.oauth-microsoft .oauth-ico { background: #0067b8; }
.oauth-tip { text-align: center; font-size: 12px; margin: 10px 0 0; }

/* ---------- 分享弹窗 ---------- */
.share-modal-body { margin-top: 10px; }
.share-expires { display: flex; gap: 16px; }
.share-expires label { display: flex; align-items: center; gap: 5px; font-size: 13px; cursor: pointer; color: var(--text); }
.share-ok { font-size: 14px; font-weight: 600; color: var(--green); margin: 8px 0 12px; }
.share-url-row { display: flex; gap: 8px; }
.share-url-row input {
  flex: 1; min-width: 0; padding: 9px 12px; border: 1px solid var(--border);
  border-radius: 8px; font-size: 13px; color: var(--text); background: var(--bg);
  outline: none;
}
.share-url-row input:focus { border-color: var(--primary); }
.share-qr { display: flex; justify-content: center; padding: 16px 0 8px; }
.share-qr img {
  width: 150px; height: 150px; border: 1px solid var(--border);
  border-radius: 10px; padding: 6px; background: #fff;
}

/* ---------------- 卡片图片 ---------------- */
.card-img {
  display: block; max-width: 100%; max-height: 220px;
  object-fit: contain; border-radius: 10px; margin: 0 auto 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,.08);
}
.thumb {
  width: 40px; height: 40px; object-fit: cover; border-radius: 8px;
  vertical-align: middle; margin-right: 8px; border: 1px solid var(--border);
}
.upload-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-top: 8px; }
#addImgPreview { position: relative; display: inline-flex; }
#addImgPreview img {
  max-width: 180px; max-height: 100px; object-fit: contain;
  border-radius: 8px; border: 1px solid var(--border); padding: 2px;
}
.img-remove {
  position: absolute; top: -7px; right: -7px; width: 20px; height: 20px;
  border-radius: 50%; background: var(--red); color: #fff; border: none;
  cursor: pointer; font-size: 11px; line-height: 20px; text-align: center; padding: 0;
}
.img-remove:hover { filter: brightness(1.15); }
.edit-img-row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 10px 0 4px; }
#mImgPreview { margin-top: 8px; width: 100%; }
#mImgPreview img {
  max-width: 100%; max-height: 180px; object-fit: contain;
  border-radius: 8px; border: 1px solid var(--border); padding: 2px;
}

/* ---------------- 牌底添加卡片按钮 ---------------- */
.panel-actions {
  display: flex; justify-content: center; gap: 10px;
  padding-top: 14px; margin-top: 14px; border-top: 1px dashed var(--border);
}
/* 弹窗内牌组下拉框 */
.modal select {
  width: 100%; padding: 9px 12px; border: 1px solid var(--border);
  border-radius: 10px; font-size: 14px; background: var(--card);
  color: var(--text); margin-bottom: 12px; box-sizing: border-box;
}
.modal select:focus { outline: none; border-color: var(--primary); }

/* 汉堡菜单按钮（仅移动端显示） */
.menu-toggle {
  display: none; /* 桌面端隐藏 */
  background: none; border: none; font-size: 22px; cursor: pointer;
  color: var(--text); padding: 4px 8px; border-radius: 8px; flex-shrink: 0;
}
.menu-toggle:active { background: #eef1f6; }

/* 侧边栏遮罩层（仅移动端） */
.sidebar-overlay {
  display: none; position: fixed; inset: 0;
  background: rgba(20, 26, 40, 0.4); z-index: 90;
}

/* ================================================================
   移动端适配 (≤768px)
   ================================================================ */
@media (max-width: 768px) {
  /* ---- 布局 ---- */
  .layout { flex-direction: column; }

  /* ---- 侧边栏 → 抽屉 ---- */
  .sidebar {
    position: fixed; top: 0; left: 0; bottom: 0;
    width: 260px; max-width: 80vw; z-index: 100;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    box-shadow: 4px 0 24px rgba(0,0,0,0.15);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-overlay { display: block; }

  /* ---- 汉堡按钮显示 ---- */
  .menu-toggle { display: block; }

  /* ---- 顶栏 ---- */
  .topbar { padding: 10px 14px; flex-wrap: wrap; gap: 8px; }
  .topbar-left { gap: 8px; flex: 1; min-width: 0; }
  .topbar h1 { font-size: 16px; }
  .tabs { padding: 3px; }
  .tab { padding: 6px 14px; font-size: 13px; }
  .guest-badge, .user-badge { font-size: 11px; padding: 2px 8px; }

  /* ---- 内容区 ---- */
  .view { padding: 14px 14px; }

  /* ---- 学习视图 ---- */
  .study-meta { flex-wrap: wrap; gap: 6px; }
  .pill { font-size: 11px; padding: 3px 10px; }
  .flashcard {
    min-height: 200px; padding: 22px 18px; border-radius: 14px;
  }
  .flashcard-front { font-size: 19px; }
  .flashcard-back { font-size: 17px; }
  .flashcard-divider { margin: 18px 0; }
  .study-controls { gap: 14px; }
  .grade-buttons { gap: 6px; }
  .grade { padding: 10px 4px; border-radius: 8px; }
  .grade b { font-size: 14px; }
  .grade i { font-size: 11px; }
  .btn.big { padding: 11px 28px; font-size: 14px; }

  /* ---- 卡片管理：添加表单竖排 ---- */
  .card-form .form-row { flex-direction: column; gap: 8px; }
  .card-form input { width: 100%; }
  .upload-row { flex-direction: row; flex-wrap: wrap; }

  /* ---- 卡片表格 → 卡片列表 ---- */
  .card-table thead { display: none; }
  .card-table, .card-table tbody, .card-table tr, .card-table td { display: block; width: 100%; }
  .card-table tr {
    border: 1px solid var(--border); border-radius: 12px;
    margin-bottom: 10px; padding: 12px 14px; background: var(--panel);
  }
  .card-table tr:hover td { background: none; }
  .card-table td { border: none; padding: 4px 0; }
  .card-table .td-front { max-width: none; font-size: 15px; }
  .card-table .td-back { max-width: none; font-size: 13px; }
  .card-table .ops { gap: 8px; margin-top: 8px; }
  .card-table .ops .btn { padding: 7px 14px; font-size: 13px; }

  /* ---- 统计 ---- */
  .stat-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .stat-card { padding: 12px 14px; }
  .stat-card .num { font-size: 22px; }
  .stat-card .label { font-size: 12px; }
  .forecast { gap: 8px; height: 140px; }
  .forecast .fbar { max-width: 32px; }
  .forecast .flabel { font-size: 11px; }

  /* ---- 面板 ---- */
  .panel { padding: 14px 16px; margin-bottom: 14px; }
  .panel h3 { font-size: 14px; }
  .panel-head { flex-wrap: wrap; gap: 8px; }
  .panel-actions { gap: 8px; }

  /* ---- 弹窗 ---- */
  .modal {
    width: 94vw; max-width: 94vw; padding: 18px 16px; border-radius: 14px;
    max-height: 90vh; overflow-y: auto;
  }
  .modal textarea { min-height: 72px; }
  .share-expires { flex-wrap: wrap; gap: 10px; }
  .share-url-row { flex-direction: column; }
  .share-url-row input { width: 100%; }
  .share-qr img { width: 130px; height: 130px; }

  /* ---- 右键菜单 → 底部弹出样式 ---- */
  .ctx-menu {
    position: fixed; bottom: 0; left: 0; right: 0; top: auto;
    min-width: none; max-width: none; width: 100%;
    border-radius: 14px 14px 0 0; padding: 8px;
  }
  .ctx-menu-title { text-align: center; max-width: none; }
  .ctx-item { padding: 12px 10px; font-size: 14px; text-align: center; }

  /* ---- 空状态 ---- */
  .empty-state { padding: 50px 0; font-size: 15px; }
  .empty-icon { font-size: 42px; }

  /* ---- Toast ---- */
  .toast { font-size: 13px; padding: 8px 16px; left: 10px; right: 10px; transform: none; max-width: none; text-align: center; }
}

/* ================================================================
   超小屏适配 (≤380px)
   ================================================================ */
@media (max-width: 380px) {
  .stat-grid { grid-template-columns: 1fr; }
  .flashcard-front { font-size: 17px; }
  .flashcard-back { font-size: 15px; }
  .grade-buttons { flex-wrap: wrap; }
  .grade { flex: 1 1 45%; }
}

/* ================================================================
   community.html / share.html 移动端适配
   ================================================================ */
@media (max-width: 768px) {
  /* community.html */
  .community-topbar, .share-topbar {
    padding: 10px 14px !important;
  }
  .community-wrap, .share-wrap {
    padding: 16px 14px 50px !important;
  }
  .community-head h1 { font-size: 18px !important; }
  .community-controls { flex-direction: column !important; align-items: stretch !important; }
  .community-search { min-width: 0 !important; width: 100% !important; }
  .community-share-item { padding: 14px 16px !important; }
  .community-share-item .name { font-size: 15px !important; }
  .community-share-item .meta { gap: 10px !important; font-size: 12px !important; }

  /* share.html */
  .share-hero { padding: 20px 18px !important; border-radius: 14px !important; }
  .share-hero h1 { font-size: 19px !important; }
  .share-hero .meta { font-size: 12px !important; }
  .share-card { padding: 14px 16px !important; }
  .share-section-title { font-size: 14px !important; margin: 22px 0 12px !important; }
}