:root {
  --bg: #f6f5f2;
  --panel: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #136f63;
  --danger: #b42318;
  --ok: #0f7b0f;
  --border: #d6d9de;
  --chip-bg: #edf7f3;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Helvetica Neue", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  background: radial-gradient(circle at 10% 10%, #eef7f3 0%, var(--bg) 40%);
  color: var(--text);
}

.container {
  max-width: 980px;
  margin: 24px auto;
  padding: 0 16px 32px;
}

.topbar h1 {
  margin: 0;
  font-size: 2rem;
}

.topbar p {
  margin-top: 6px;
  color: #374151;
}

.project-link {
  margin-top: 8px;
}

.project-link a {
  color: var(--primary);
  font-weight: 700;
  text-decoration: none;
}

.project-link a:hover {
  text-decoration: underline;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-top: 14px;
}

.row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

label {
  font-weight: 600;
}

select,
button,
input[type="number"] {
  border-radius: 8px;
  border: 1px solid var(--border);
  padding: 8px 12px;
  font-size: 14px;
  background: #fff;
}

input[type="number"] {
  width: 96px;
}

button {
  background: var(--primary);
  color: #fff;
  border: none;
  cursor: pointer;
}

button:hover {
  filter: brightness(0.95);
}

button:disabled {
  cursor: not-allowed;
  background: #9ca3af;
}

.checkbox {
  font-weight: 500;
}

.score {
  display: grid;
  grid-template-columns: repeat(4, minmax(120px, 1fr));
  gap: 10px;
}

#timer {
  font-weight: 700;
  color: var(--danger);
}

.q-header {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.95rem;
}

.tags {
  margin-top: 8px;
  margin-bottom: 6px;
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  padding: 3px 9px;
  border-radius: 999px;
  border: 1px solid #c4e2d9;
  background: var(--chip-bg);
  font-size: 12px;
  color: #0f4f45;
}

#q-text {
  margin-top: 8px;
  margin-bottom: 14px;
  line-height: 1.45;
}

#q-image {
  max-width: 100%;
  border-radius: 10px;
  margin-bottom: 12px;
  display: none;
}

#options {
  display: grid;
  gap: 10px;
}

.option-btn {
  text-align: left;
  border: 1px solid var(--border);
  background: #fdfdfd;
  color: var(--text);
}

.option-btn.selected {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(19, 111, 99, 0.15);
}

.option-btn.correct {
  border-color: var(--ok);
  background: #eaf8ea;
}

.option-btn.wrong {
  border-color: var(--danger);
  background: #fdeceb;
}

#answer-result {
  min-height: 24px;
  font-weight: 700;
}

#answer-result.ok {
  color: var(--ok);
}

#answer-result.bad {
  color: var(--danger);
}

.knowledge-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.knowledge-table th,
.knowledge-table td {
  border-top: 1px solid var(--border);
  padding: 8px;
  text-align: left;
}

.knowledge-table th {
  color: var(--muted);
  font-weight: 600;
}

.wrong-item {
  border-top: 1px solid var(--border);
  padding: 10px 0;
}

.wrong-item:first-child {
  border-top: none;
}

.wrong-item h4 {
  margin: 0 0 8px;
}

.hidden {
  display: none;
}

.note {
  color: var(--muted);
  font-size: 0.92rem;
}

.links h3 {
  margin-top: 0;
}

.links ul {
  margin: 0;
  padding-left: 20px;
  line-height: 1.7;
}

.links a {
  color: var(--primary);
  text-decoration: none;
}

.links a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .score {
    grid-template-columns: repeat(2, minmax(120px, 1fr));
  }

  input[type="number"] {
    width: 84px;
  }
}