/* ==========================================
   初中刷题小助手 — 全局样式
   ========================================== */

:root {
  --primary: #4f6ef7;
  --primary-light: #eef1ff;
  --success: #22c55e;
  --success-light: #f0fdf4;
  --danger: #ef4444;
  --danger-light: #fef2f2;
  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --bg: #f5f6fa;
  --card: #fff;
  --text: #1e293b;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --shadow: 0 1px 3px rgba(0,0,0,.08);
  --radius: 12px;
}

/* ===== 基础重置 ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  padding-bottom: 80px;
}

/* ===== 布局容器 ===== */
.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px;
}

/* ===== 头部 ===== */
.header {
  text-align: center;
  padding: 24px 0 12px;
}

.header h1 {
  font-size: 1.6rem;
  color: var(--primary);
}

.header .sub {
  font-size: .85rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ===== 卡片 ===== */
.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}

.card h3 {
  font-size: 1.05rem;
  margin-bottom: 12px;
  color: var(--text);
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: 8px;
  border: none;
  font-size: .92rem;
  cursor: pointer;
  font-weight: 500;
  transition: all .15s;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  opacity: .9;
}

.btn-outline {
  background: #fff;
  color: var(--primary);
  border: 1.5px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary-light);
}

.btn-success {
  background: var(--success);
  color: #fff;
}

.btn-danger {
  background: var(--danger);
  color: #fff;
}

.btn-sm {
  padding: 6px 14px;
  font-size: .82rem;
}

.btn-block {
  display: flex;
  width: 100%;
}

.btn:disabled {
  opacity: .5;
  cursor: not-allowed;
}

.btn-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.btn-danger-text {
  background: none;
  color: var(--danger);
}

/* ===== 首页模式卡片 ===== */
.mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.mode-card {
  background: var(--card);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 14px;
  text-align: center;
  cursor: pointer;
  transition: all .15s;
}

.mode-card:hover {
  border-color: var(--primary);
  background: var(--primary-light);
}

.mode-card .icon {
  font-size: 1.8rem;
  margin-bottom: 6px;
}

.mode-card .label {
  font-weight: 600;
  font-size: .95rem;
}

.mode-card .desc {
  font-size: .78rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ===== 筛选器 ===== */
.filter-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
}

.filter-chip {
  padding: 6px 14px;
  border-radius: 20px;
  border: 1.5px solid var(--border);
  background: #fff;
  font-size: .82rem;
  cursor: pointer;
  transition: all .15s;
}

.filter-chip.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* ===== 刷题页 ===== */
.quiz-progress {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

.progress-bar {
  flex: 1;
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 3px;
  transition: width .3s;
}

.progress-text {
  font-size: .82rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

.question-meta {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 12px;
  font-size: .75rem;
  font-weight: 500;
}

.badge-type {
  background: var(--primary-light);
  color: var(--primary);
}

.badge-subject {
  background: #fef3c7;
  color: #92400e;
}

.badge-diff {
  background: #fce7f3;
  color: #be185d;
}

.question-text {
  font-size: 1.05rem;
  font-weight: 500;
  margin-bottom: 18px;
  line-height: 1.7;
}

/* ===== 选项列表 ===== */
.option-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all .15s;
  font-size: .95rem;
}

.option-item:hover {
  border-color: var(--primary);
  background: var(--primary-light);
}

.option-item.selected {
  border-color: var(--primary);
  background: var(--primary-light);
}

.option-item.correct {
  border-color: var(--success);
  background: var(--success-light);
}

.option-item.wrong {
  border-color: var(--danger);
  background: var(--danger-light);
}

.option-item.no-pointer {
  pointer-events: none;
}

.option-item .dot {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: .75rem;
  font-weight: 700;
  transition: all .15s;
}

.option-item.selected .dot {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

.option-item.correct .dot {
  border-color: var(--success);
  background: var(--success);
  color: #fff;
}

.option-item.wrong .dot {
  border-color: var(--danger);
  background: var(--danger);
  color: #fff;
}

/* ===== 填空题输入框 ===== */
.fill-input {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: .95rem;
  outline: none;
  transition: border-color .15s;
}

.fill-input:focus {
  border-color: var(--primary);
}

/* ===== 反馈区域 ===== */
.feedback-box {
  margin-top: 14px;
  padding: 14px;
  border-radius: 8px;
  font-size: .9rem;
  line-height: 1.6;
}

.feedback-box.correct {
  background: var(--success-light);
  color: #166534;
}

.feedback-box.wrong {
  background: var(--danger-light);
  color: #991b1b;
}

.feedback-box .fb-title {
  font-weight: 600;
  margin-bottom: 4px;
}

.correct-answer-display {
  margin-top: 8px;
  font-size: .88rem;
  color: var(--text-secondary);
}

/* ===== 操作栏 ===== */
.action-bar {
  display: flex;
  gap: 8px;
  margin-top: 14px;
  flex-wrap: wrap;
  align-items: center;
}

.quiz-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

/* ===== 列表项 ===== */
.list-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.list-item:last-child {
  border-bottom: none;
}

.list-item .info {
  flex: 1;
  min-width: 0;
}

.list-item .title {
  font-size: .9rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.list-item .meta {
  font-size: .78rem;
  color: var(--text-secondary);
}

/* ===== 统计面板 ===== */
.stat-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.stat-item {
  text-align: center;
  padding: 16px 10px;
  background: var(--bg);
  border-radius: 8px;
}

.stat-item .num {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-item .label {
  font-size: .78rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* ===== 标签切换 ===== */
.tab-row {
  display: flex;
  gap: 0;
  margin-bottom: 16px;
  border-bottom: 2px solid var(--border);
}

.tab-btn {
  padding: 8px 18px;
  border: none;
  background: none;
  font-size: .88rem;
  cursor: pointer;
  color: var(--text-secondary);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all .15s;
}

.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
}

/* ===== 底部导航栏 ===== */
.nav-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--card);
  border-top: 1px solid var(--border);
  display: flex;
  z-index: 100;
}

.nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 8px 4px;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: .7rem;
  transition: color .15s;
  border: none;
  background: none;
}

.nav-item .nav-icon {
  font-size: 1.2rem;
  margin-bottom: 2px;
}

.nav-item.active {
  color: var(--primary);
}

/* ===== 模态框 ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.4);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal {
  background: var(--card);
  border-radius: var(--radius);
  padding: 24px;
  width: 100%;
  max-width: 500px;
  max-height: 80vh;
  overflow-y: auto;
}

.modal h3 {
  margin-bottom: 14px;
}

.form-group {
  margin-bottom: 12px;
}

.form-group label {
  display: block;
  font-size: .85rem;
  font-weight: 500;
  margin-bottom: 4px;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: .9rem;
  outline: none;
  font-family: inherit;
}

.form-group textarea {
  resize: vertical;
  min-height: 60px;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--primary);
}

.form-hint {
  font-size: .75rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* ===== 空状态 ===== */
.empty {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-secondary);
}

.empty .icon {
  font-size: 2.5rem;
  margin-bottom: 10px;
}

.empty p {
  font-size: .9rem;
}

/* ===== 通用 ===== */
.hidden {
  display: none !important;
}

.mark-btn {
  background: none;
  border: none;
  font-size: 1.3rem;
  cursor: pointer;
  padding: 4px;
  color: var(--text-secondary);
  transition: color .15s;
}

.mark-btn.marked {
  color: var(--warning);
}

/* ===== 响应式 (移动端) ===== */
@media (max-width: 480px) {
  .mode-grid {
    grid-template-columns: 1fr;
  }

  .stat-grid {
    grid-template-columns: 1fr 1fr;
  }

  .container {
    padding: 10px;
  }

  .card {
    padding: 14px;
  }
}

/* ===== 庆祝动画 ===== */
.celebration-overlay {
  position: fixed;
  inset: 0;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, .45);
  animation: overlayFadeIn .3s ease;
  pointer-events: all;
}

.celebration-overlay.fade-out {
  animation: overlayFadeOut .5s ease forwards;
}

@keyframes overlayFadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes overlayFadeOut {
  from { opacity: 1; }
  to   { opacity: 0; }
}

.celebration-text {
  font-size: 3rem;
  font-weight: 900;
  text-align: center;
  z-index: 1001;
  animation: celebBounce .6s cubic-bezier(.17,.67,.83,.67);
  text-shadow: 0 0 20px rgba(255,255,255,.8);
  /* 彩虹渐变文字 */
  background: linear-gradient(90deg, #ff6b6b, #ffd93d, #6bcb77, #4d96ff, #ff6b6b);
  background-size: 200% auto;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: celebBounce .6s cubic-bezier(.17,.67,.83,.67), rainbowShift 2s linear infinite;
  padding: 0 20px;
  max-width: 90vw;
  word-break: keep-all;
}

@keyframes celebBounce {
  0%   { transform: scale(0); opacity: 0; }
  50%  { transform: scale(1.3); }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes rainbowShift {
  0%   { background-position: 0% center; }
  100% { background-position: 200% center; }
}

/* 烟花粒子容器 */
.fireworks-container {
  position: fixed;
  inset: 0;
  z-index: 1000;
  pointer-events: none;
  overflow: hidden;
}

.firework-particle {
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  animation: fireworkBurst 1.8s ease-out forwards;
}

@keyframes fireworkBurst {
  0% {
    transform: translate(0, 0) scale(1);
    opacity: 1;
  }
  60% {
    opacity: 1;
  }
  100% {
    transform: translate(var(--dx), var(--dy)) scale(0);
    opacity: 0;
  }
}

/* 烟花升空轨迹 */
.firework-rocket {
  position: absolute;
  bottom: 0;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  animation: rocketUp .6s ease-out forwards;
  z-index: 999;
}

@keyframes rocketUp {
  0% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  100% {
    transform: translateY(var(--ry)) scale(1);
    opacity: .6;
  }
}