/* ============ 通用 ============ */
:root {
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --text: #303133;
  --text-secondary: #606266;
  --border: #e4e7ed;
  --primary: #409EFF;
  --success: #67C23A;
  --danger: #F56C6C;
  --warning: #E6A23C;
  --info: #909399;
  --shadow: 0 2px 12px rgba(0,0,0,0.06);
}

[data-theme="dark"] {
  --bg: #1a1a1a;
  --card-bg: #262626;
  --text: #e5e5e5;
  --text-secondary: #a0a0a0;
  --border: #3a3a3a;
  --shadow: 0 2px 12px rgba(0,0,0,0.3);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
    "Microsoft YaHei", "微软雅黑", sans-serif;
  -webkit-font-smoothing: antialiased;
  transition: background-color .25s ease, color .25s ease;
}

#app { min-height: 100vh; }

/* 加载页 */
.app-loading {
  display: flex; flex-direction: column;
  justify-content: center; align-items: center;
  height: 100vh;
}
.spinner {
  width: 40px; height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ============ 布局 ============ */
.layout {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
.layout-header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  padding: 12px 20px;
  display: flex; align-items: center;
  position: sticky; top: 0; z-index: 100;
  box-shadow: var(--shadow);
}
.layout-header .logo {
  font-size: 18px; font-weight: 600;
  color: var(--primary);
  margin-right: 30px;
  cursor: pointer;
}
.layout-nav {
  display: flex; gap: 4px;
  flex: 1;
}
.layout-nav .nav-item {
  padding: 6px 14px;
  border-radius: 6px;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 14px;
  transition: all .2s ease;
  text-decoration: none;
}
.layout-nav .nav-item:hover { background: var(--bg); color: var(--text); }
.layout-nav .nav-item.active {
  background: var(--primary);
  color: white;
}
.layout-header .theme-toggle {
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 6px;
  color: var(--text-secondary);
  font-size: 18px;
  user-select: none;
}
.layout-header .theme-toggle:hover { background: var(--bg); }

.layout-main {
  flex: 1;
  padding: 20px;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

/* ============ 卡片 ============ */
.card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 20px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}
.card-title {
  font-size: 16px; font-weight: 600;
  margin: 0 0 16px;
  color: var(--text);
}

/* ============ 刷题页 ============ */
.practice-container {
  max-width: 800px; margin: 0 auto;
}
.q-progress {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 16px;
}
.q-progress .bar {
  flex: 1;
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}
.q-progress .bar > div {
  height: 100%;
  background: var(--primary);
  transition: width .3s ease;
}
.q-stem {
  font-size: 16px; line-height: 1.7;
  margin-bottom: 20px;
  white-space: pre-wrap;
}
.q-meta {
  font-size: 12px; color: var(--text-secondary);
  margin-bottom: 12px;
}
.q-meta .tag {
  display: inline-block;
  padding: 2px 8px;
  background: var(--bg);
  border-radius: 4px;
  margin-right: 6px;
}
.q-options { display: flex; flex-direction: column; gap: 10px; }
.q-option {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all .2s ease;
  background: var(--card-bg);
}
.q-option:hover { border-color: var(--primary); }
.q-option.selected {
  border-color: var(--primary);
  background: rgba(64,158,255,.08);
}
.q-option.correct {
  border-color: var(--success);
  background: rgba(103,194,58,.12);
}
.q-option.wrong {
  border-color: var(--danger);
  background: rgba(245,108,108,.12);
}
.q-option .letter {
  flex-shrink: 0;
  width: 28px; height: 28px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  background: var(--bg);
  font-weight: 600;
  font-size: 14px;
}
.q-option.selected .letter,
.q-option.correct .letter,
.q-option.wrong .letter { background: currentColor; color: white; }
.q-option.correct .letter { background: var(--success); color: white; }
.q-option.wrong .letter { background: var(--danger); color: white; }
.q-option .text { flex: 1; line-height: 1.5; }

.q-actions {
  display: flex; gap: 10px; margin-top: 20px;
  flex-wrap: wrap;
}
.q-explanation {
  margin-top: 20px;
  padding: 16px;
  background: var(--bg);
  border-radius: 8px;
  border-left: 4px solid var(--primary);
}
.q-explanation .label {
  font-weight: 600; margin-bottom: 8px;
  color: var(--primary);
}
.q-explanation .content {
  white-space: pre-wrap;
  line-height: 1.7;
  font-size: 14px;
  color: var(--text-secondary);
}

/* ============ 状态栏 ============ */
.q-toolbar {
  display: flex; gap: 8px; justify-content: space-between;
  align-items: center;
  margin-top: 16px;
  padding: 12px; background: var(--card-bg);
  border-radius: 8px;
  flex-wrap: wrap;
}
.q-toolbar .btn-icon {
  background: transparent; border: none; padding: 6px 10px;
  cursor: pointer; color: var(--text-secondary);
  border-radius: 4px;
}
.q-toolbar .btn-icon:hover { background: var(--bg); }
.q-toolbar .btn-icon.active { color: var(--warning); }

/* ============ 通用动画 ============ */
.fade-enter-active, .fade-leave-active {
  transition: opacity .25s ease;
}
.fade-enter-from, .fade-leave-to { opacity: 0; }

.slide-enter-active, .slide-leave-active {
  transition: all .3s ease;
}
.slide-enter-from { transform: translateX(20px); opacity: 0; }
.slide-leave-to { transform: translateX(-20px); opacity: 0; }

/* 设置项 grid */
.setup-row {
  display: flex; align-items: flex-start;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.setup-row:last-child { border-bottom: none; }
.setup-label {
  width: 100px; flex-shrink: 0;
  color: var(--text-secondary);
  font-size: 14px; line-height: 32px;
}
.setup-options {
  flex: 1;
  display: flex; flex-wrap: wrap; gap: 8px;
}
.setup-chip {
  padding: 6px 14px;
  border-radius: 16px;
  border: 1px solid var(--border);
  cursor: pointer;
  font-size: 13px;
  transition: all .2s ease;
  user-select: none;
  background: var(--card-bg);
}
.setup-chip:hover { border-color: var(--primary); }
.setup-chip.active {
  background: var(--primary); color: white; border-color: var(--primary);
}

/* 表格 */
.simple-table { width: 100%; border-collapse: collapse; }
.simple-table th, .simple-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  font-size: 14px;
}
.simple-table th { color: var(--text-secondary); font-weight: 500; }

/* 响应式 */
@media (max-width: 768px) {
  .layout-main { padding: 12px; }
  .layout-header { padding: 10px 12px; }
  .layout-header .logo { margin-right: 12px; font-size: 16px; }
  .layout-nav .nav-item { padding: 6px 8px; font-size: 13px; }
  .setup-row { flex-direction: column; }
  .setup-label { width: 100%; line-height: 1.5; margin-bottom: 6px; }
  .q-stem { font-size: 15px; }
}

/* Element Plus 暗色模式适配 */
[data-theme="dark"] .el-message,
[data-theme="dark"] .el-card,
[data-theme="dark"] .el-dialog,
[data-theme="dark"] .el-input__wrapper,
[data-theme="dark"] .el-select__wrapper {
  background: var(--card-bg) !important;
  color: var(--text) !important;
}
[data-theme="dark"] .el-input__inner { color: var(--text) !important; }

/* 工具类 */
.flex { display: flex; }
.flex-1 { flex: 1; }
.text-sec { color: var(--text-secondary); }
.text-xs { font-size: 12px; }
.text-sm { font-size: 13px; }
.mt-8 { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mt-20 { margin-top: 20px; }
.mb-8 { margin-bottom: 8px; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }
.empty-state {
  text-align: center; padding: 60px 20px;
  color: var(--text-secondary);
}
.empty-state .icon { font-size: 48px; margin-bottom: 12px; opacity: .5; }

/* ============ 登录页 ============ */
.login-page {
  display: flex; justify-content: center; align-items: center;
  min-height: 100vh;
  padding: 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}
[data-theme="dark"] .login-page {
  background: linear-gradient(135deg, #2c3e50 0%, #1a1a2e 100%);
}
.login-card {
  width: 100%; max-width: 400px;
  background: var(--card-bg);
  padding: 40px 32px;
  border-radius: 12px;
  box-shadow: 0 20px 60px rgba(0,0,0,.2);
}
.login-logo {
  font-size: 22px; font-weight: 600; color: var(--primary);
  text-align: center;
  margin-bottom: 28px;
}
.login-hint {
  margin-top: 16px; text-align: center;
}
.layout-main--login { padding: 0; max-width: none; }

/* 登录/注册 Tab */
.login-tabs {
  display: flex;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
}
.login-tab {
  flex: 1;
  text-align: center;
  padding: 10px 0;
  font-size: 15px;
  color: var(--text-secondary);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: all .2s;
  user-select: none;
}
.login-tab:hover { color: var(--text); }
.login-tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
}

/* 验证码 */
.captcha-row {
  display: flex; align-items: stretch; gap: 8px;
}
.captcha-img {
  width: 120px; height: 40px;
  flex-shrink: 0;
  cursor: pointer;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  display: flex; align-items: center; justify-content: center;
  background: #f0f2f5;
  transition: border-color .2s;
}
.captcha-img:hover { border-color: var(--primary); }
.captcha-img svg { display: block; width: 100%; height: 100%; }
.captcha-loading {
  font-size: 14px; color: var(--text-secondary);
}

/* ============ 用户菜单 ============ */
.user-menu {
  display: flex; align-items: center; gap: 10px;
  margin-left: 12px;
}
.user-name {
  font-size: 13px;
  color: var(--text-secondary);
  padding: 4px 8px;
  display: flex; align-items: center; gap: 6px;
}
.user-badge {
  font-size: 10px;
  background: var(--primary); color: white;
  padding: 1px 6px; border-radius: 8px;
}
.logout-btn {
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 18px;
  color: var(--text-secondary);
}
.logout-btn:hover { background: var(--bg); color: var(--danger); }