/**
 * Unified Button System - 统一按钮尺寸系统
 *
 * 职责：全局浮动按钮尺寸标准化
 * 作用域：TOC、Chatbot、沉浸模式等浮动按钮
 * 依赖：variables.css
 *
 * 提取自：unified-button-sizes.css
 *
 * 包含：
 * - 按钮尺寸变量系统
 * - 圆形按钮样式类
 * - 响应式尺寸调整
 * - 无障碍支持
 */

/* ==================== 1. 按钮尺寸变量系统 ==================== */

:root {
  /* 桌面端按钮尺寸（适中尺寸，不会太小） */
  --btn-small-size: 40px;    /* TOC按钮等 */
  --btn-medium-size: 44px;   /* Chatbot等 */
  --btn-large-size: 42px;    /* 沉浸式按钮等 */

  /* 移动端按钮尺寸（适度缩小但保持可用性） */
  --btn-small-mobile: 36px;
  --btn-medium-mobile: 40px;
  --btn-large-mobile: 44px;

  /* 对应的图标尺寸 */
  --btn-icon-small: 18px;
  --btn-icon-medium: 20px;
  --btn-icon-large: 19px;

  /* 移动端图标尺寸 */
  --btn-icon-small-mobile: 16px;
  --btn-icon-medium-mobile: 18px;
  --btn-icon-large-mobile: 18px;
}

/* ==================== 2. 基础按钮样式 ==================== */

/* Tiny Round Button (小型圆形按钮) - 极简低调风格 */
.tiny-round-btn {
  border-radius: 50% !important;
  background-color: rgba(255, 255, 255, 0.9) !important;
  backdrop-filter: blur(4px);
  color: #94a3b8 !important; /* slate-400 */
  border: 1px solid #e2e8f0 !important;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05) !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  cursor: pointer !important;
  padding: 0 !important;
  opacity: 0.6; /* 默认低透明度，减少视觉干扰 */
  transition: all 0.2s ease !important;

  width: var(--btn-small-size) !important;
  height: var(--btn-small-size) !important;
  font-size: var(--btn-icon-small) !important;
}

.tiny-round-btn:hover {
  opacity: 1;
  color: #3b82f6 !important; /* blue-500 */
  border-color: #bfdbfe !important; /* blue-200 */
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15) !important;
  transform: translateY(-2px);
}

.tiny-round-btn:active {
  transform: translateY(0);
  background-color: #f8fafc !important;
}

/* 移动端适配 */
@media (max-width: 768px) {
  .tiny-round-btn {
    opacity: 0.8; /* 移动端稍微不那么透明，因为没有 hover */
  }
}

/* Medium Round Button (中型圆形按钮) */
.medium-round-btn {
  border-radius: 50% !important;
  background-color: var(--color-primary) !important;
  color: white !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.15) !important;
  border: none !important;
  cursor: pointer !important;
  padding: 0 !important;
  transition: background-color var(--transition-fast),
              transform var(--transition-fast) !important;

  width: var(--btn-medium-size) !important;
  height: var(--btn-medium-size) !important;
  font-size: var(--btn-icon-medium) !important;
}

.medium-round-btn:hover {
  background-color: #1d4ed8 !important;
  transform: scale(1.08);
}

/* Large Round Button (大型圆形按钮) */
.big-round-btn,
.large-round-btn {
  border-radius: 50% !important;
  background-color: var(--color-primary) !important;
  color: white !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.15) !important;
  border: none !important;
  cursor: pointer !important;
  padding: 0 !important;
  transition: background-color var(--transition-fast),
              transform var(--transition-fast) !important;

  width: var(--btn-large-size) !important;
  height: var(--btn-large-size) !important;
  font-size: var(--btn-icon-large) !important;
}

.big-round-btn:hover,
.large-round-btn:hover {
  background-color: #1d4ed8 !important;
  transform: scale(1.08);
}

/* ==================== 3. 图标样式 ==================== */

.tiny-round-btn > i,
.medium-round-btn > i,
.big-round-btn > i,
.large-round-btn > i {
  font-size: inherit !important;
  line-height: 1 !important;
  padding: 0 !important;
}

/* ==================== 4. 特定按钮尺寸覆盖 ==================== */

/* 沉浸式布局按钮 */
#toggle-immersive-btn {
  width: var(--btn-large-size) !important;
  height: var(--btn-large-size) !important;
  font-size: var(--btn-icon-large) !important;
}

/* Chatbot FAB */
#chatbot-fab {
  width: var(--btn-medium-size) !important;
  height: var(--btn-medium-size) !important;
  font-size: var(--btn-icon-medium) !important;
}

/* Chatbot FAB按钮样式 - 极简低调风格（与 floatingHistoryBtn 一致） */
.chatbot-fab-button {
  width: var(--btn-medium-size) !important;
  height: var(--btn-medium-size) !important;
  border-radius: 50% !important;
  background-color: rgba(255, 255, 255, 0.9) !important;
  backdrop-filter: blur(4px);
  color: #94a3b8 !important; /* slate-400 */
  border: 1px solid #e2e8f0 !important;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05) !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  cursor: pointer !important;
  padding: 0 !important;
  opacity: 0.6; /* 默认低透明度，减少视觉干扰 */
  transition: all 0.2s ease !important;
  outline: none !important;
}

.chatbot-fab-button i {
  font-size: var(--btn-icon-medium) !important;
  line-height: 1 !important;
}

.chatbot-fab-button:hover {
  opacity: 1;
  color: #3b82f6 !important; /* blue-500 */
  border-color: #bfdbfe !important; /* blue-200 */
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15) !important;
  transform: translateY(-2px);
}

.chatbot-fab-button:active {
  transform: translateY(0);
  background-color: #f8fafc !important;
}

/* ==================== 5. 响应式设计 ==================== */

/* 平板设备优化 (768px - 1024px) */
@media (max-width: 1024px) and (min-width: 769px) {
  .tiny-round-btn {
    width: 38px !important;
    height: 38px !important;
    font-size: 17px !important;
  }

  .medium-round-btn {
    width: 42px !important;
    height: 42px !important;
    font-size: 19px !important;
  }

  .big-round-btn,
  .large-round-btn {
    width: 40px !important;
    height: 40px !important;
    font-size: 19px !important;
  }

  .chatbot-fab-button {
    width: 42px !important;
    height: 42px !important;
  }

  .chatbot-fab-button i {
    font-size: 19px !important;
  }

  #toggle-immersive-btn {
    width: 40px !important;
    height: 40px !important;
    font-size: 19px !important;
  }
}

/* 移动端响应式设计 (700px以下) */
@media (max-width: 700px) {
  :root {
    --btn-small-size: var(--btn-small-mobile);
    --btn-medium-size: var(--btn-medium-mobile);
    --btn-large-size: var(--btn-large-mobile);
    --btn-icon-small: var(--btn-icon-small-mobile);
    --btn-icon-medium: var(--btn-icon-medium-mobile);
    --btn-icon-large: var(--btn-icon-large-mobile);
  }

  .tiny-round-btn {
    width: var(--btn-small-mobile) !important;
    height: var(--btn-small-mobile) !important;
    font-size: var(--btn-icon-small-mobile) !important;
  }

  .medium-round-btn {
    width: var(--btn-medium-mobile) !important;
    height: var(--btn-medium-mobile) !important;
    font-size: var(--btn-icon-medium-mobile) !important;
  }

  .big-round-btn,
  .large-round-btn {
    width: var(--btn-large-mobile) !important;
    height: var(--btn-large-mobile) !important;
    font-size: var(--btn-icon-large-mobile) !important;
  }

  #chatbot-fab {
    width: var(--btn-medium-mobile) !important;
    height: var(--btn-medium-mobile) !important;
    font-size: var(--btn-icon-medium-mobile) !important;
  }

  .chatbot-fab-button {
    width: var(--btn-medium-mobile) !important;
    height: var(--btn-medium-mobile) !important;
    opacity: 0.8; /* 移动端稍微不那么透明，因为没有 hover */
  }

  .chatbot-fab-button i {
    font-size: var(--btn-icon-medium-mobile) !important;
  }

  #toggle-immersive-btn {
    width: var(--btn-large-mobile) !important;
    height: var(--btn-large-mobile) !important;
    font-size: var(--btn-icon-large-mobile) !important;
  }
}

/* 极小屏幕设备 (400px以下) */
@media (max-width: 400px) {
  .tiny-round-btn {
    width: 34px !important;
    height: 34px !important;
    font-size: 15px !important;
  }

  .medium-round-btn {
    width: 38px !important;
    height: 38px !important;
    font-size: 17px !important;
  }

  .big-round-btn,
  .large-round-btn {
    width: 42px !important;
    height: 42px !important;
    font-size: 19px !important;
  }

  #chatbot-fab {
    width: 38px !important;
    height: 38px !important;
    font-size: 17px !important;
  }

  .chatbot-fab-button {
    width: 38px !important;
    height: 38px !important;
  }

  .chatbot-fab-button i {
    font-size: 17px !important;
  }
}

/* ==================== 6. 无障碍支持 ==================== */

/* 减少动画偏好 */
@media (prefers-reduced-motion: reduce) {
  .tiny-round-btn,
  .medium-round-btn,
  .big-round-btn,
  .large-round-btn {
    transition: background-color var(--transition-fast) !important;
  }

  .tiny-round-btn:hover,
  .medium-round-btn:hover,
  .big-round-btn:hover,
  .large-round-btn:hover {
    transform: none !important;
  }
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
  .tiny-round-btn,
  .medium-round-btn,
  .big-round-btn,
  .large-round-btn {
    border: 2px solid currentColor !important;
    box-shadow: none !important;
  }
}

/* ==================== 7. 暗色模式适配 ==================== */

@media (prefers-color-scheme: dark) {
  .tiny-round-btn {
    background-color: rgba(30, 41, 59, 0.9) !important; /* slate-800 with opacity */
    color: #cbd5e1 !important; /* slate-300 */
    border-color: #475569 !important; /* slate-600 */
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3) !important;
  }

  .tiny-round-btn:hover {
    color: #60a5fa !important; /* blue-400 */
    border-color: #3b82f6 !important; /* blue-500 */
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25) !important;
  }

  .tiny-round-btn:active {
    background-color: rgba(15, 23, 42, 0.95) !important; /* slate-900 */
  }

  .medium-round-btn,
  .big-round-btn,
  .large-round-btn {
    background-color: #1e40af !important;
    box-shadow: 0 2px 8px rgba(30, 64, 175, 0.3) !important;
  }

  .medium-round-btn:hover,
  .big-round-btn:hover,
  .large-round-btn:hover {
    background-color: #1e3a8a !important;
  }

  .chatbot-fab-button {
    background-color: rgba(30, 41, 59, 0.9) !important; /* slate-800 with opacity */
    color: #cbd5e1 !important; /* slate-300 */
    border-color: #475569 !important; /* slate-600 */
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3) !important;
  }

  .chatbot-fab-button:hover {
    color: #60a5fa !important; /* blue-400 */
    border-color: #3b82f6 !important; /* blue-500 */
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25) !important;
  }

  .chatbot-fab-button:active {
    background-color: rgba(15, 23, 42, 0.95) !important; /* slate-900 */
  }
}