* { box-sizing: border-box; }

:root {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --border: #e3e6ea;
  --text: #1f2328;
  --muted: #6b7280;
  --primary: #2f6feb;
  --primary-hover: #1f5cd6;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.04);
  --radius: 10px;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 14px;
  line-height: 1.6;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 12px 24px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  font-weight: 600;
  font-size: 16px;
}

.tabs {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.tab {
  background: transparent;
  border: 0;
  padding: 8px 14px;
  border-radius: 6px;
  cursor: pointer;
  color: var(--muted);
  font-size: 14px;
}

.tab:hover { color: var(--text); background: #eef0f3; }
.tab.active { background: var(--primary); color: white; }

main {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}

.card h2 {
  margin: 0 0 12px;
  font-size: 16px;
}

.muted { color: var(--muted); }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }

input[type=text], input[type=password], textarea, select {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font: inherit;
  background: white;
  color: var(--text);
}

textarea { resize: vertical; }

label {
  display: block;
  margin-bottom: 4px;
  font-weight: 500;
}

.field { margin-bottom: 12px; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

button.btn {
  background: var(--primary);
  color: white;
  border: 0;
  padding: 8px 16px;
  border-radius: 6px;
  cursor: pointer;
  font: inherit;
}
button.btn:hover { background: var(--primary-hover); }
button.btn:disabled { opacity: 0.5; cursor: not-allowed; }
button.btn.secondary { background: #eef0f3; color: var(--text); }
button.btn.secondary:hover { background: #e3e6ea; }
button.btn.danger { background: var(--danger); }
button.btn.btn-sm { padding: 4px 10px; font-size: 13px; }

.assignment-image {
  display: block;
  max-width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 12px;
}

.scenario-box {
  background: #fafbfc;
  border-left: 3px solid var(--primary);
  padding: 12px 16px;
  border-radius: 4px;
  margin-bottom: 12px;
  white-space: pre-wrap;
}

.focus-tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 12px;
  background: #fff7e6;
  color: #b58105;
  font-size: 12px;
  margin-left: 8px;
}

.char-count {
  text-align: right;
  color: var(--muted);
  font-size: 12px;
  margin-top: 6px;
}
.char-count.ok { color: var(--success); }

.draft-status {
  font-size: 12px;
  min-width: 58px;
}
.draft-status.draft-error { color: var(--danger); }

.scores-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 10px;
}

.score-cell {
  background: #fafbfc;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px 12px;
}

.score-cell .dim { font-weight: 500; }
.score-cell .val {
  float: right;
  font-weight: 600;
  color: var(--primary);
}
.score-cell .val.score-high { color: #16a34a; }
.score-cell .val.score-low  { color: #dc2626; }
.score-cell.score-high-bg   { background: #f0fdf4; border-color: #bbf7d0; }
.score-cell.score-low-bg    { background: #fff1f2; border-color: #fecdd3; }

.feedback-block {
  margin-top: 8px;
  font-size: 13px;
  color: var(--muted);
}
.feedback-block .label { color: var(--text); font-weight: 500; }

.history-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.history-list li {
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
  cursor: pointer;
}
.history-list li:hover { background: #fafbfc; }
.history-list li:last-child { border-bottom: 0; }

.history-group-title {
  margin: 18px 0 8px;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  text-transform: none;
}

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: #1f2328;
  color: white;
  padding: 10px 16px;
  border-radius: 6px;
  opacity: 0;
  transition: all .25s;
  pointer-events: none;
  z-index: 100;
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
.toast.error { background: var(--danger); }

.empty {
  text-align: center;
  color: var(--muted);
  padding: 32px;
}

.chart-wrap {
  position: relative;
  height: 360px;
}

.segmented-row {
  justify-content: space-between;
}

.segmented {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 6px;
}

.segmented-btn {
  background: #eef0f3;
  color: var(--text);
  border: 0;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  font: inherit;
}

.segmented-btn.active {
  background: var(--primary);
  color: white;
}

.writing-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 16px;
  align-items: start;
}
@media (max-width: 720px) {
  .writing-layout { grid-template-columns: 1fr; }
}

.tips-panel {
  background: #fafbfc;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  font-size: 13px;
}
.tips-panel h3 {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--primary);
}
.tips-panel .tips-focus {
  color: var(--text);
  margin-bottom: 12px;
  line-height: 1.6;
  padding: 8px 10px;
  background: #eef3ff;
  border-radius: 6px;
}
.tips-panel ul {
  margin: 0;
  padding-left: 16px;
  color: var(--muted);
  line-height: 1.9;
}
.tips-panel ul li::marker { color: var(--primary); }

details.dim-detail {
  margin: 6px 0;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 12px;
}
details.dim-detail summary {
  cursor: pointer;
  font-weight: 500;
}

/* 登录覆盖层 */
.auth-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.auth-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 40px 36px;
  width: 360px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.auth-title {
  margin: 0;
  font-size: 20px;
  font-weight: 600;
}

.auth-hint {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
}

.auth-input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 15px;
  outline: none;
  background: var(--bg);
  color: var(--text);
}

.auth-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(47,111,235,0.12);
}

.auth-btn {
  width: 100%;
  padding: 10px;
  font-size: 15px;
}

/* 退出按钮 */
.logout-btn {
  margin-left: auto;
  font-size: 13px;
  padding: 5px 12px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--muted);
  cursor: pointer;
}

.logout-btn:hover {
  color: var(--danger);
  border-color: var(--danger);
  background: transparent;
}

.material-tabs {
  margin: 16px 0 10px;
}

.material-item,
.source-row,
.brief-row,
.ai-block {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
  margin: 10px 0;
  background: #fff;
}

.material-item p {
  margin: 8px 0;
  line-height: 1.7;
}

.source-row,
.brief-row {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
}

.check-row {
  display: flex;
  gap: 8px;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
}

.ai-block pre {
  white-space: pre-wrap;
  margin: 8px 0 0;
  color: var(--muted);
  font-family: inherit;
  line-height: 1.7;
}

.fiction-note {
  background: #fff7ed;
  border-left: 3px solid #f97316;
  border-radius: 8px;
  padding: 8px 10px;
  color: #7c2d12;
}