:root {
  --primary: #4A6CF7;
  --primary-light: #EEF1FE;
  --danger: #EF4444;
  --danger-light: #FEF2F2;
  --bg: #F5F7FB;
  --card: #FFFFFF;
  --text: #1F2937;
  --text-muted: #9CA3AF;
  --border: #E5E7EB;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
  background: var(--bg);
  color: var(--text);
  max-width: 480px;
  margin: 0 auto;
  padding: 16px;
  min-height: 100vh;
}

/* ── Header ── */
header {
  text-align: center;
  padding: 20px 0 12px;
}
.header-top {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
header h1 { font-size: 22px; font-weight: 700; color: var(--primary); }
header p { font-size: 13px; color: var(--text-muted); margin-top: 4px; }
.user-bar {
  position: absolute;
  right: 0;
  display: flex;
  align-items: center;
  gap: 8px;
}
.user-name {
  font-size: 12px;
  color: var(--text-muted);
  font-weight: 500;
}
.btn-logout {
  font-size: 11px;
  color: var(--danger);
  text-decoration: none;
  padding: 2px 8px;
  border: 1px solid var(--danger);
  border-radius: 4px;
  transition: all .2s;
}
.btn-logout:hover {
  background: var(--danger);
  color: #FFF;
}

/* ── Tabs ── */
.tabs {
  display: flex;
  background: var(--card);
  border-radius: var(--radius);
  padding: 4px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}
.tab {
  flex: 1;
  padding: 10px 0;
  border: none;
  background: transparent;
  font-size: 14px;
  cursor: pointer;
  border-radius: 10px;
  color: var(--text-muted);
  transition: all .2s;
}
.tab.active {
  background: var(--primary);
  color: #FFF;
  font-weight: 600;
}

/* ── Tab content ── */
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ── Date row ── */
.date-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-size: 14px;
  font-weight: 600;
}
.date-row input[type="date"] {
  flex: 1;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
}

/* ── Card ── */
.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 12px;
  box-shadow: var(--shadow);
}
.card h2 { font-size: 15px; margin-bottom: 2px; }
.card-desc { font-size: 12px; color: var(--text-muted); margin-bottom: 12px; }

/* ── Dynamic items ── */
.item-row {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  margin-bottom: 8px;
}
.item-row input[type="text"],
.item-row textarea {
  flex:1;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 13px;
  font-family: inherit;
  resize: vertical;
}
.item-row textarea { min-height: 40px; }
.item-row .idx {
  font-size: 12px;
  color: var(--text-muted);
  min-width: 20px;
  padding-top: 10px;
}
.btn-del {
  background: none;
  border: none;
  color: var(--danger);
  font-size: 18px;
  cursor: pointer;
  padding: 6px 4px;
  line-height: 1;
}
.btn-del:hover { opacity: 0.7; }

/* 责善改过 双输入 */
.mistake-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}
.mistake-group .label-hint {
  font-size: 11px;
  color: var(--text-muted);
  padding-left: 2px;
}

/* ── Study items ── */
.study-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
}
.study-row input[type="text"] {
  flex: 1;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 13px;
  font-family: inherit;
}
.study-row input[type="checkbox"] {
  width: 18px; height: 18px;
  accent-color: var(--primary);
  flex-shrink: 0;
}

/* ── Buttons ── */
.btn-add {
  display: block;
  width: 100%;
  padding: 8px;
  margin-top: 8px;
  border: 1px dashed var(--primary);
  background: var(--primary-light);
  color: var(--primary);
  font-size: 13px;
  border-radius: 8px;
  cursor: pointer;
  transition: all .2s;
}
.btn-add:hover { background: #DDE3FD; }

.btn-save {
  display: block;
  width: 100%;
  padding: 14px;
  margin-top: 8px;
  border: none;
  background: var(--primary);
  color: #FFF;
  font-size: 16px;
  font-weight: 600;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all .2s;
}
.btn-save:hover { opacity: 0.9; transform: translateY(-1px); }

/* ── Week nav ── */
.week-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 16px 0;
}
.btn-nav {
  padding: 8px 16px;
  border: 1px solid var(--border);
  background: var(--card);
  border-radius: 8px;
  font-size: 13px;
  cursor: pointer;
}
#week-label {
  font-size: 14px;
  font-weight: 600;
  min-width: 140px;
  text-align: center;
}

/* ── Score ── */
.score-display { text-align: center; padding: 20px 0 8px; }
.score-num { font-size: 56px; font-weight: 800; color: var(--primary); }
.score-unit { font-size: 20px; color: var(--text-muted); margin-left: 4px; }
.score-text { text-align: center; font-size: 14px; margin-bottom: 16px; }

/* ── Details ── */
.details-list { margin-top: 8px; }
.details-list .detail-row {
  padding: 10px 16px;
  background: var(--card);
  border-radius: 8px;
  margin-bottom: 6px;
  font-size: 13px;
  box-shadow: var(--shadow);
}

/* ── History ── */
#history-list { margin-top: 4px; }
.history-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  background: var(--card);
  border-radius: var(--radius);
  margin-bottom: 8px;
  box-shadow: var(--shadow);
}
.history-row .info { flex: 1; }
.history-row .info .date { font-weight: 600; font-size: 14px; color: var(--primary); }
.history-row .info .preview { font-size: 12px; color: var(--text-muted); margin-top: 4px; }
.history-row .btn-del-history {
  background: var(--danger-light);
  border: none;
  color: var(--danger);
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 12px;
  cursor: pointer;
  flex-shrink: 0;
  margin-left: 12px;
}
.history-row .btn-del-history:hover { opacity: 0.8; }

/* ── Toast ── */
.toast {
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s;
  white-space: nowrap;
}
.toast.show { opacity: 1; pointer-events: auto; }
.toast.success { background: #10B981; color: #FFF; }
.toast.error { background: var(--danger); color: #FFF; }
.toast.info { background: var(--primary); color: #FFF; }