/* 默认浅色模式变量 */
:root {
  --primary-color: #6f42c1;
  --secondary-color: #0d6efd;
  --success-color: #198754;
  --card-bg: rgba(255, 255, 255, 0.95);
  --body-bg: #f8f9fa;
  --text-color: #212529;
  --text-secondary: #6c757d;
  --card-text: #212529;
  --border-radius: 12px;
  --shadow: 0 10px 20px rgba(0, 0, 0, 0.08);
  --transition: all 0.3s ease;
}

/* 跟随系统暗色模式 */
@media (prefers-color-scheme: dark) {
  :root {
    --primary-color: #9d7fe8;
    --secondary-color: #5d9cff;
    --success-color: #20c997;
    --card-bg: rgba(33, 37, 41, 0.95);
    --body-bg: #121212;
    --text-color: #f8f9fa;
    --text-secondary: #adb5bd;
    --card-text: #f8f9fa;
    --shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  }

  /* 输入框 */
  .form-control {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.15);
    color: #f8f9fa !important;  /* 用户输入文本为白色 */
  }
  .form-control:focus {
    background: rgba(255, 255, 255, 0.12);
    border-color: var(--primary-color);
    color: #f8f9fa !important;
  }
  .form-control::placeholder {
    color: #adb5bd;
    opacity: 0.8;
  }

  /* 卡片 */
  .card {
    background: rgba(30, 33, 37, 0.95);
    border: 1px solid rgba(255, 255, 255, 0.1);
  }

  /* 按钮 */
  .btn-primary {
    background: linear-gradient(to right, #7d5cd1, #4a7eff);
    color: white;
  }
  .btn-primary:hover {
    background: linear-gradient(to right, #6a4bb8, #3a6ae0);
  }

  /* 示例框 */
  .example-box {
    background: rgba(111, 66, 193, 0.2);
    border-left: 4px solid var(--primary-color);
    color: var(--card-text);
  }

  /* 次要文字 */
  .text-muted {
    color: var(--text-secondary) !important;
  }

  /* 警告框 */
  .alert-info {
    background-color: rgba(13, 202, 240, 0.15);
    border-color: rgba(13, 202, 240, 0.3);
    color: var(--card-text);
  }

  /* 输入组文本 */
  .input-group-text {
    background: rgba(111, 66, 193, 0.2);
    border-color: rgba(255, 255, 255, 0.15);
    color: var(--primary-color);
  }

  /* 页面背景 */
  body {
    background: linear-gradient(135deg, #0f0f0f 0%, #1a1a1a 100%);
  }
}

/* 公共文字颜色 */
body, .card, .card-body, .example-box, 
.form-control, .form-label, .input-group-text,
.alert, .footer, .btn, .text-muted {
  color: var(--text-color);
  transition: var(--transition);
}

/* 卡片内文本 */
.card-body, .card-header, .card-body p, 
.card-body label, .card-body .form-label,
.card-body .small, .card-body .text-muted {
  color: var(--card-text);
}

/* 浅色模式占位符 */
.form-control::placeholder {
  color: #6c757d;
  opacity: 0.8;
}

/* 输入框默认颜色 */
.form-control {
  color: var(--text-color);
}

/* 页面背景 */
body {
  background: linear-gradient(135deg, var(--body-bg) 0%, #e2e8f0 100%);
  background-attachment: fixed;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  padding: 20px;
  min-height: 100vh;
  transition: var(--transition);
}

/* 头部 */
.header {
  text-align: center;
  margin-bottom: 30px;
  padding-top: 20px;
}
.header h1 {
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 10px;
  font-size: 2.5rem;
}
.header p {
  color: var(--text-color);
  opacity: 0.8;
  max-width: 700px;
  margin: 0 auto;
}

/* 卡片 */
.card {
  background: var(--card-bg);
  border: none;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  margin-bottom: 25px;
  transition: var(--transition);
  overflow: hidden;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}
.card-header {
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  color: white;
  font-weight: 600;
  padding: 15px 20px;
  border-bottom: none;
  position: relative;
}
.card-header::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(to right, var(--success-color), rgba(255, 255, 255, 0.3));
}
.card-body {
  padding: 25px;
}

/* 示例框 */
.example-box {
  background: rgba(111, 66, 193, 0.05);
  border-left: 4px solid var(--primary-color);
  padding: 15px;
  border-radius: 0 8px 8px 0;
  margin-bottom: 15px;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
}

/* 按钮 */
.btn-primary {
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  border: none;
  padding: 10px 20px;
  font-weight: 600;
  transition: var(--transition);
  color: white;
}
.btn-primary:hover {
  background: linear-gradient(to right, #5a32a3, #0a58ca);
  transform: translateY(-2px);
  color: white;
}
.btn-info {
  background: var(--secondary-color);
  border: none;
  transition: var(--transition);
  color: white;
}
.btn-info:hover {
  background: #0a58ca;
  transform: translateY(-2px);
  color: white;
}
.btn-success {
  background: var(--success-color);
  border: none;
  transition: var(--transition);
  color: white;
}
.btn-success:hover {
  background: #157347;
  transform: translateY(-2px);
  color: white;
}

/* 输入组文本 */
.input-group-text {
  background: rgba(111, 66, 193, 0.1);
  border: none;
  color: var(--primary-color);
}

/* 表单控件 */
.form-control {
  border: 1px solid rgba(0, 0, 0, 0.1);
  padding: 12px;
  transition: var(--transition);
}
.form-control:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 0.25rem rgba(111, 66, 193, 0.25);
}

/* 页脚 */
.footer {
  text-align: center;
  padding: 20px;
  opacity: 0.7;
  font-size: 0.9rem;
}
.footer a {
  color: var(--primary-color);
  text-decoration: none;
}
.footer a:hover {
  text-decoration: underline;
}

/* 主题切换按钮 */
.theme-switch {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--primary-color);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow);
  z-index: 100;
  transition: var(--transition);
}
.theme-switch:hover {
  transform: scale(1.1);
}

/* Toast 提示 */
.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--success-color);
  color: white;
  padding: 12px 25px;
  border-radius: 50px;
  box-shadow: var(--shadow);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 1000;
}
.toast.show {
  opacity: 1;
}

/* 响应式 */
@media (max-width: 768px) {
  .header h1 {
    font-size: 2rem;
  }
  .card-body {
    padding: 20px;
  }
}