:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --ink: #1f2a37;
  --muted: #6b7785;
  --line: #e3e9f0;
  --primary: #2f6fed;
  --primary-d: #1f55c7;
  --accent: #14b8a6;
  --warn: #f59e0b;
  --danger: #ef4444;
  --ok: #22c55e;
  --radius: 12px;
  --shadow: 0 2px 10px rgba(31, 42, 55, .06);
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg); color: var(--ink); font-size: 14px; line-height: 1.6;
}
#app { display: flex; height: 100vh; height: -webkit-fill-available; height: 100dvh; height: calc(var(--vh, 1vh) * 100); }

/* Sidebar */
.sidebar {
  width: 232px; background: #0f1b2d; color: #cfd8e3; display: flex; flex-direction: column;
  padding: 18px 14px; flex-shrink: 0;
}
.brand { display: flex; align-items: center; gap: 10px; margin-bottom: 18px; }
.logo {
  width: 38px; height: 38px; border-radius: 10px; background: linear-gradient(135deg, var(--primary), var(--accent));
  display: flex; align-items: center; justify-content: center; font-size: 20px; color: #fff; font-weight: 700;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-text strong { color: #fff; }
.brand-text small { color: #6b7785; font-size: 11px; }
.nav { display: flex; flex-direction: column; gap: 4px; flex: 1; }
.nav button {
  text-align: left; background: transparent; border: 0; color: #cfd8e3; padding: 10px 12px;
  border-radius: 8px; cursor: pointer; font-size: 14px; transition: .15s;
}
.nav button:hover { background: rgba(255,255,255,.06); }
.nav button.active { background: var(--primary); color: #fff; font-weight: 600; }
.sidebar-foot { border-top: 1px solid rgba(255,255,255,.08); padding-top: 12px; }
.grade-pick label { font-size: 12px; color: #8a97a8; display: block; margin-bottom: 4px; }
.grade-pick select {
  width: 100%; padding: 7px 8px; border-radius: 8px; border: 1px solid rgba(255,255,255,.12);
  background: #16263b; color: #fff; font-size: 13px;
}
.streak { margin-top: 10px; font-size: 12px; color: #ffd27a; }

/* Main */
.main { flex: 1; display: flex; flex-direction: column; min-width: 0; }
.topbar {
  height: 60px; background: var(--panel); border-bottom: 1px solid var(--line); display: flex;
  align-items: center; justify-content: space-between; padding: 0 22px; flex-shrink: 0;
  max-width: 1100px; margin: 0 auto; width: 100%;
}
.topbar h1 { font-size: 18px; margin: 0; }
.topbar-right { display: flex; align-items: center; gap: 12px; }
.today { color: var(--muted); font-size: 13px; }
.content { padding: 22px; padding-bottom: max(22px, env(safe-area-inset-bottom, 0px)); overflow-y: auto; flex: 1; max-width: 1100px; margin: 0 auto; width: 100%; }

/* Cards */
.card {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; box-shadow: var(--shadow); margin-bottom: 16px;
}
.grid { display: grid; gap: 16px; }
.grid.cols-2 { grid-template-columns: 1fr 1fr; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 980px){ .grid.cols-2,.grid.cols-3{ grid-template-columns: 1fr; } }

/* Buttons */
.btn {
  border: 0; border-radius: 8px; padding: 8px 14px; cursor: pointer; font-size: 13px;
  background: var(--primary); color: #fff; transition: .15s;
}
.btn:hover { background: var(--primary-d); }
.btn.ghost { background: transparent; color: var(--muted); border: 1px solid var(--line); }
.btn.ghost:hover { color: var(--ink); border-color: var(--muted); }
.btn.ok { background: var(--ok); }
.btn.sm { padding: 5px 10px; font-size: 12px; }

/* Subjects */
.subj-tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 14px; }
.subj-tabs button {
  border: 1px solid var(--line); background: var(--panel); border-radius: 20px; padding: 6px 14px;
  cursor: pointer; font-size: 13px; color: var(--muted);
}
.subj-tabs button.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.tag { display: inline-block; font-size: 11px; padding: 2px 8px; border-radius: 6px; background: #eef3fb; color: var(--primary); margin-right: 6px; }
.task-list { list-style: none; padding: 0; margin: 0; }
.task-list li { padding: 9px 0; border-bottom: 1px dashed var(--line); display: flex; align-items: flex-start; gap: 10px; }
.task-list li:last-child { border-bottom: 0; }
.task-list .num { color: var(--accent); font-weight: 700; flex-shrink: 0; }
.focus-box { background: #f0f7ff; border-left: 3px solid var(--primary); padding: 10px 12px; border-radius: 6px; color: #28456e; }

/* Drill */
.q-card { border: 1px solid var(--line); border-radius: 10px; padding: 14px; margin-bottom: 12px; }
.q-card .q-subj { font-size: 11px; color: var(--primary); font-weight: 600; }
.q-card .q-text { font-size: 15px; margin: 8px 0; }
.opt { display: block; padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; margin: 6px 0; cursor: pointer; }
.opt:hover { border-color: var(--primary); }
.opt.correct { background: #e7f9ee; border-color: var(--ok); }
.opt.wrong { background: #fdeaea; border-color: var(--danger); }
.opt.chosen { border-color: var(--primary); }
.q-input { width: 100%; padding: 9px; border: 1px solid var(--line); border-radius: 8px; font-size: 14px; }
.explain { margin-top: 8px; font-size: 13px; color: var(--muted); background: #f7f9fc; padding: 8px 10px; border-radius: 6px; }
.result-bar { display: flex; gap: 14px; align-items: center; margin-bottom: 12px; }

/* Schedule */
.week-grid { display: grid; grid-template-columns: 80px repeat(7, 1fr); gap: 6px; overflow-x: auto; }
.week-grid .cell { background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 6px; min-height: 38px; font-size: 12px; text-align: center; }
.week-grid .head { background: #eef3fb; font-weight: 600; color: var(--primary); }
.week-grid .rest { color: var(--muted); }
.todo-item { display: flex; align-items: center; gap: 10px; padding: 8px 0; border-bottom: 1px dashed var(--line); }
.todo-item.done .todo-text { text-decoration: line-through; color: var(--muted); }
.todo-check { width: 18px; height: 18px; cursor: pointer; }
.pomo { display: flex; align-items: center; gap: 12px; }
.pomo .time { font-size: 34px; font-weight: 700; letter-spacing: 2px; font-variant-numeric: tabular-nums; }

/* Library */
.lib-filters { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 14px; align-items: center; }
.lib-filters select, .lib-filters input { padding: 7px 9px; border: 1px solid var(--line); border-radius: 8px; font-size: 13px; }
.book { border: 1px solid var(--line); border-radius: 10px; padding: 12px; background: var(--panel); }
.book h4 { margin: 0 0 4px; font-size: 15px; }
.book .author { color: var(--muted); font-size: 12px; margin-bottom: 8px; }
.book .must { color: var(--danger); font-size: 11px; margin-left: 6px; }
.status-pick { display: flex; gap: 6px; }
.status-pick button { font-size: 11px; padding: 3px 8px; border-radius: 6px; border: 1px solid var(--line); background: #fff; cursor: pointer; color: var(--muted); }
.status-pick button.on { background: var(--primary); color: #fff; border-color: var(--primary); }
.stat-pills { display: flex; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.pill { background: var(--panel); border: 1px solid var(--line); border-radius: 20px; padding: 6px 14px; font-size: 13px; }
.pill b { color: var(--primary); }

/* Oral */
.scene-card { border: 1px solid var(--line); border-radius: 10px; padding: 14px; margin-bottom: 12px; background: var(--panel); }
.sentence { padding: 8px 10px; border-radius: 8px; background: #f7f9fc; margin: 6px 0; }
.sentence .en { font-weight: 600; }
.sentence .zh { color: var(--muted); font-size: 12px; margin-left: 8px; }
.rec-row { display: flex; gap: 10px; align-items: center; margin: 10px 0; }
.card-chip { display: inline-block; border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; margin: 6px 6px 0 0; background: #f7f9fc; font-size: 13px; }
.card-chip .tag2 { color: var(--accent); font-size: 11px; display:block; }

/* AI */
.chat { border: 1px solid var(--line); border-radius: 10px; padding: 14px; height: 320px; overflow-y: auto; background: #fbfcfe; margin-bottom: 10px; }
.bubble { max-width: 80%; padding: 9px 12px; border-radius: 12px; margin-bottom: 10px; font-size: 14px; white-space: pre-wrap; }
.bubble.me { background: var(--primary); color: #fff; margin-left: auto; }
.bubble.ai { background: #eef3fb; color: var(--ink); }
.ai-config { border: 1px dashed var(--line); border-radius: 8px; padding: 10px; margin-top: 10px; font-size: 12px; color: var(--muted); }
.ai-config input { width: 100%; padding: 7px; border: 1px solid var(--line); border-radius: 6px; margin: 4px 0; font-size: 12px; }

/* Toast */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%) translateY(20px);
  background: #1f2a37; color: #fff; padding: 10px 18px; border-radius: 10px; font-size: 13px;
  opacity: 0; pointer-events: none; transition: .25s; z-index: 99;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

.empty { color: var(--muted); text-align: center; padding: 30px; }
.section-title { font-size: 15px; font-weight: 700; margin: 0 0 10px; }
.muted { color: var(--muted); }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }

/* Login */
.login-mask {
  position: fixed; inset: 0; background: linear-gradient(135deg, #0f1b2d, #1f2a44);
  display: none; align-items: center; justify-content: center; z-index: 200;
}
.login-card {
  background: #fff; border-radius: 16px; padding: 32px 28px; width: 340px; max-width: 90vw;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .3);
}
.login-card h2 { margin: 0 0 6px; font-size: 22px; }
.login-card .muted { margin: 0 0 18px; }
.login-card input {
  width: 100%; padding: 11px 12px; border: 1px solid var(--line); border-radius: 9px;
  margin-bottom: 12px; font-size: 14px; box-sizing: border-box;
}
.login-row { display: flex; gap: 10px; }
.login-row .btn { flex: 1; }
.login-err { color: var(--danger); font-size: 13px; min-height: 18px; margin-top: 8px; }
.user-box { display: flex; align-items: center; gap: 8px; }
.user-tag { font-size: 13px; color: var(--muted); }

/* 修改密码弹窗（复用登录层视觉） */
.modal-mask {
  position: fixed; inset: 0; background: rgba(15, 27, 45, .55);
  display: none; align-items: center; justify-content: center; z-index: 210;
}
.modal-card {
  background: #fff; border-radius: 16px; padding: 28px 26px; width: 340px; max-width: 90vw;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .3);
}
.modal-card h3 { margin: 0 0 16px; font-size: 18px; }
.modal-card input {
  width: 100%; padding: 11px 12px; border: 1px solid var(--line); border-radius: 9px;
  margin-bottom: 12px; font-size: 14px; box-sizing: border-box;
}

/* iPad 竖屏 / 手机（含横屏）/ 窄屏适配：侧栏改为顶部横向导航，避免内容被挤压 */
@media (max-width: 920px) {
  #app { flex-direction: column; }
  .sidebar {
    width: auto; flex-direction: row; align-items: center; gap: 10px;
    padding: 10px 12px; overflow-x: auto; flex-shrink: 0;
  }
  .brand { margin-bottom: 0; flex-shrink: 0; }
  .brand-text small { display: none; }
  .nav { flex-direction: row; flex: 1; overflow-x: auto; gap: 6px; }
  .nav button { white-space: nowrap; padding: 8px 12px; }
  .sidebar-foot {
    flex-direction: row; border-top: 0; padding-top: 0; gap: 10px;
    align-items: center; flex-shrink: 0;
  }
  .grade-pick { margin-bottom: 0; }
  .grade-pick label { display: none; }
  .grade-pick select { width: auto; padding: 5px 8px; }
  .streak { margin-top: 0; white-space: nowrap; }
  .topbar { padding: 0 14px; max-width: none; }
  .content { padding: 16px; font-size: 15px; line-height: 1.7; max-width: none; }
}