/* ============================================================
   theme.css — Obsidian Flashcard 统一样式表
   所有颜色使用 CSS 变量，便于统一管理和主题切换
   ============================================================ */

/* ── CSS 变量定义 ── */
:root {
  /* 品牌色 */
  --color-primary: #07c160;
  --color-primary-hover: #059653;
  --color-primary-active: #06a854;
  --color-primary-light: #e8f8ee;
  --color-primary-disabled: #a5d6a7;

  /* 页面背景 */
  --bg-page: #f5f5f5;
  --bg-page-alt: #f5f7fa;
  --bg-card: #ffffff;
  --bg-hover: #f0f0f0;
  --bg-active: #e8f8ee;

  /* 文字颜色 */
  --text-primary: #1d2129;
  --text-secondary: #333;
  --text-muted: #555;
  --text-muted2: #666;
  --text-placeholder: #999;
  --text-inverse: #ffffff;
  --text-tag: #888;

  /* 边框 */
  --border: #e0e0e0;
  --border-light: #f0f0f0;
  --border-focus: var(--color-primary);

  /* 状态色 */
  --color-success: #52c41a;
  --color-error: #e53935;
  --color-error-bg: #fef0f0;
  --color-error-strong: #cf1322;
  --color-warning: #fa8c16;

  /* 徽章色 */
  --badge-teacher-bg: #e8f4ff;
  --badge-teacher-text: #1890ff;
  --badge-student-bg: #fff7e6;
  --badge-student-text: #fa8c16;
  --badge-super-bg: #fff1f0;
  --badge-super-text: #cf1322;
  --badge-normal-bg: #f0f5ff;
  --badge-normal-text: #1677ff;
  --badge-none-bg: #f5f5f5;
  --badge-none-text: #999;

  /* 辅助灰 */
  --gray-100: #fafafa;
  --gray-200: #f5f5f5;
  --gray-300: #eee;
  --gray-400: #ddd;
  --gray-500: #bbb;
  --gray-600: #aaa;
  --gray-700: #999;
  --gray-800: #888;
  --gray-900: #666;

  /* 标签/分类色 */
  --tag-bg: #f0f0f0;
  --tag-text: #555;
  --tag-active-bg: var(--color-primary);
  --tag-active-text: var(--text-inverse);

  /* 阴影 */
  --shadow-sm: 0 1px 4px rgba(0,0,0,0.07);
  --shadow-sm-hover: 0 2px 8px rgba(0,0,0,0.12);
  --shadow-md: 0 2px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.4);

  /* 圆角 */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 999px;

  /* 滚动条 */
  --scrollbar-track: transparent;
  --scrollbar-thumb: #ddd;
  --scrollbar-thumb-hover: #ccc;

  /* header */
  --header-bg: var(--color-primary);
  --header-btn-bg: rgba(255,255,255,0.2);
  --header-btn-hover: rgba(255,255,255,0.3);
  --header-btn-active: rgba(255,255,255,0.4);
}

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

/* ── 通用 HTML/Body ── */
html, body {
  height: 100%;
  font-family: -apple-system, -apple-system-cache, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  -webkit-font-smoothing: antialiased;
}

body {
  display: flex;
  flex-direction: column;
  background: var(--bg-page-alt);
}

/* ── 页面标题（在统一 header 左侧）── */
.header-page-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-inverse);
  margin: 0;
  padding: 0 4px 0 0;
  white-space: nowrap;
  flex-shrink: 0;
}

/* ── 通用 Header ── */
header {
  background: var(--header-bg);
  color: var(--text-inverse);
  padding: 14px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-shrink: 0;
  user-select: none;
}

/* 主导航区 — 左对齐 */
.header-left {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: nowrap;
}

/* 管理员按钮 + 退出区 — 右对齐 */
.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.header-stats-bar {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-right: 8px;
}

.stat-pill {
  background: rgba(255,255,255,0.18);
  border-radius: 10px;
  padding: 3px 8px;
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  color: #fff;
}

.header-btn {
  background: var(--header-btn-bg);
  border: none;
  color: var(--text-inverse);
  padding: 6px 14px;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 13px;
  transition: background 0.15s;
  white-space: nowrap;
}

.header-btn:hover { background: var(--header-btn-hover); }
.header-btn.active { background: var(--header-btn-active); cursor: default; }
.header-btn.red { background: rgba(255,80,80,0.3); }
.header-btn.red:hover { background: rgba(255,100,100,0.5); }

#identitySelect {
  background: var(--header-btn-bg);
  border: 1px solid rgba(255,255,255,0.3);
  color: var(--text-inverse);
  padding: 4px 8px;
  border-radius: var(--radius-md);
  font-size: 12px;
  cursor: pointer;
  width: 80px;
  outline: none;
}

#identitySelect option { background: var(--color-primary); color: var(--text-inverse); }

/* ── Toast ── */
#toast {
  position: fixed;
  bottom: 60px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0,0,0,0.75);
  color: var(--text-inverse);
  padding: 8px 20px;
  border-radius: var(--radius-full);
  font-size: 14px;
  z-index: 9999;
  display: none;
  pointer-events: none;
}

/* ── 通用 Main ── */
.main {
  flex: 1;
  overflow: hidden;
  display: flex;
  min-height: 0;
  position: relative;
}

/* ── 通用空状态 ── */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 60px 20px;
  color: var(--text-placeholder);
  font-size: 14px;
  gap: 8px;
}

.empty-icon { font-size: 32px; }

/* ── 通用滚动条 ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--scrollbar-track); }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--scrollbar-thumb-hover); }

/* ── 通用辅助类 ── */
.hidden { display: none; }

/* ── INDEX / 登录页 ── */
body.login-page {
  background: var(--bg-page);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  margin: 0;
}

.login-box {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  padding: 40px;
  width: 360px;
  max-width: 100%;
  box-shadow: var(--shadow-md);
  margin: auto;
}

.login-box h2 {
  text-align: center;
  margin-bottom: 30px;
  color: var(--text-secondary);
}

.tab-bar { display: flex; gap: 8px; margin-bottom: 24px; }

.tab {
  flex: 1;
  padding: 10px;
  text-align: center;
  border-radius: var(--radius-md);
  cursor: pointer;
  background: var(--bg-hover);
  color: var(--text-muted2);
  font-size: 14px;
  transition: all 0.2s;
}

.tab.active {
  background: var(--color-primary);
  color: var(--text-inverse);
  font-weight: 600;
}

.input-group { margin-bottom: 16px; }

input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 14px;
  outline: none;
  transition: border-color 0.2s;
}

input:focus { border-color: var(--color-primary); }
input[disabled] { background: var(--bg-page); color: var(--text-placeholder); }

.btn {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--text-inverse);
}

.btn-primary:hover { opacity: 0.85; }
.btn-primary:disabled {
  background: var(--color-primary-disabled);
  cursor: not-allowed;
}

.msg {
  text-align: center;
  font-size: 13px;
  margin-top: 12px;
  min-height: 18px;
}

.msg.error { color: var(--color-error); }
.msg.success { color: var(--color-primary); }

.hint {
  font-size: 11px;
  color: var(--text-placeholder);
  margin-top: 6px;
  text-align: center;
}