/* Kimi Style Theme - Fully Optimized */

:root {
  /* Kimi 核心颜色系统 */
  --km-primary: #1a73e8; /* 主色调，接近 Google/Kimi 蓝 */
  --km-primary-hover: #1557b0;
  --km-primary-light: #e8f0fe; /* 浅蓝背景 */
  
  /* 背景色 */
  --km-bg-main: #ffffff; /* 主内容区背景 */
  --km-bg-sidebar: #f9f9f9; /* 侧边栏极浅灰 */
  --km-bg-hover: #f1f3f4; /* 悬停背景 */
  --km-bg-active: #e8eaed; /* 激活/选中背景 */
  --km-bg-input: #f1f3f4; /* 输入框背景 */
  
  /* 文本色 */
  --km-text-primary: #202124; /* 主要文字 */
  --km-text-secondary: #5f6368; /* 次要文字 */
  --km-text-tertiary: #dadce0; /* 占位符/极淡文字 */
  
  /* 边框与分割线 */
  --km-border: #dadce0;
  --km-border-light: #f1f3f4;
  
  /* 阴影 */
  --km-shadow-sm: 0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15);
  --km-shadow-md: 0 4px 6px rgba(32,33,36,0.28);
  --km-shadow-card: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
  
  /* 尺寸与圆角 */
  --km-radius-sm: 4px;
  --km-radius-md: 8px;
  --km-radius-lg: 12px;
  --km-radius-xl: 24px; /* 用于大按钮或输入框 */
  
  /* 字体 */
  --km-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  
  /* 布局参数 */
  --km-sidebar-width: 220px;
}

body {
  font-family: var(--km-font-family);
  color: var(--km-text-primary);
  background-color: var(--km-bg-main);
  -webkit-font-smoothing: antialiased;
}

/* ==========================================================================
   Task 2: 侧边栏样式升级 (Sidebar)
   ========================================================================== */

.sidebar {
  background-color: var(--km-bg-sidebar);
  border-right: none;
  /* 增加一点右侧阴影让层级更分明，或者保持无边框的扁平感 */
  /* box-shadow: 1px 0 0 0 var(--km-border-light); */
  padding: 16px 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sidebar h1 {
  font-size: 18px;
  font-weight: 600;
  color: var(--km-text-primary);
  padding: 0 12px 12px;
  margin: 0;
  /* border-bottom: 1px solid var(--km-border-light); */
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 新建会话按钮 - 醒目置顶，保持固定不滚动 */
.new-chat-btn {
  width: calc(100% - 24px);
  background-color: #ffffff;
  color: var(--km-primary);
  border: 1px solid var(--km-border); /* 只有极淡边框 */
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  border-radius: var(--km-radius-xl); /* 大圆角 */
  padding: 12px 16px;
  margin: 0;
  font-weight: 500;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.new-chat-btn:hover {
  background-color: #ffffff;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  transform: translateY(-1px);
  color: var(--km-primary-hover);
}

.new-chat-btn .new-icon {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.new-chat-btn .action-label {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* 会话列表容器 */
.scrollable-section {
  flex: 1;
  overflow-y: auto;
  padding: 0;
  margin-right: -8px; /* 抵消滚动条位置 */
  padding-right: 8px;
}

/* 隐藏不必要的 Section 标题 */
.section h3 {
  display: none;
}

/* 会话按钮 */
.btn-session {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 10px 12px;
  margin: 4px 0;
  border-radius: var(--km-radius-md);
  color: var(--km-text-secondary);
  background-color: transparent;
  border: none;
  font-size: 14px;
  transition: background-color 0.15s ease;
  position: relative;
}

.btn-session:hover {
  background-color: var(--km-bg-hover);
  color: var(--km-text-primary);
}

.btn-session.active {
  background-color: var(--km-bg-active);
  color: var(--km-text-primary);
  font-weight: 500;
}

.btn-session .session-name {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 1;
}

/* 底部用户信息区域 */
.fixed-bottom-section {
  border-top: 1px solid var(--km-border);
  padding: 12px 0 0 0;
  margin: 0;
  background-color: transparent;
}

.user-section {
  position: static; /* 覆盖原来的 absolute */
  padding: 0;
  margin: 0;
  width: 100%;
}

.user-info {
  display: flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: var(--km-radius-md);
  background: transparent;
  box-shadow: none;
  color: var(--km-text-primary);
  transition: background 0.15s ease;
}

.user-info:hover {
  background-color: var(--km-bg-hover);
  transform: none;
  box-shadow: none;
}

.user-avatar {
  width: 32px;
  height: 32px;
  background: var(--km-primary);
  font-size: 14px;
  margin-right: 12px;
  box-shadow: none;
}

.user-name {
  color: var(--km-text-primary);
  font-size: 14px;
  font-weight: 500;
}

.user-level {
  color: var(--km-text-secondary);
  font-size: 12px;
}

/* ==========================================================================
   Task 3: 欢迎页 (Welcome View) 重构
   ========================================================================== */

.main-content {
  background-color: var(--km-bg-main);
}

/* 头部 Header */
.header {
  height: 60px;
  padding: 0 24px;
  border-bottom: 1px solid var(--km-border-light); /* 恢复底部边框，让它更像一个独立的栏 */
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

/* 当侧边栏可见时，Header的左padding应该减少，使标题靠左 */
body:not(.sidebar-hidden) .header {
  padding-left: 24px;
}

/* 当侧边栏隐藏时，Header的左padding应该增加，为展开按钮留出空间 */
body.sidebar-hidden .header {
  padding-left: 60px;
}

/* Session Title Dropdown Container */
.session-title-container {
    display: flex;
    align-items: center;
    gap: 4px;
    cursor: pointer;
    margin-right: auto; /* Push to far left */
    padding: 4px 8px;
    border-radius: var(--km-radius-md);
    transition: background-color 0.2s;
    max-width: 300px;
    position: relative; /* 确保下拉菜单相对于此容器定位 */
}

.session-title-container:hover {
    background-color: var(--km-bg-hover);
}

.header h2 {
  font-size: 16px;
  font-weight: 600;
  color: var(--km-text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin: 0;
}

.title-arrow {
    color: var(--km-text-secondary);
    flex-shrink: 0;
}

/* Remove old edit pencil style */
.header h2::after {
    display: none;
}

/* Header Session Dropdown Menu */
.header-session-menu {
    position: absolute;
    top: 48px; /* 直接位于标题正下方 */
    left: 0;   /* 与容器左对齐 */
    background: #ffffff;
    border: 1px solid var(--km-border-light);
    border-radius: var(--km-radius-md);
    box-shadow: var(--km-shadow-md);
    min-width: 140px;
    z-index: 2000;
    padding: 4px;
    display: none;
}

.header-session-menu.show {
    display: block;
}

body.sidebar-hidden .header-session-menu {
    left: 60px;
}

.header-menu-item {
    padding: 8px 10px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    border-radius: var(--km-radius-sm);
    font-size: 13px; /* 字体比标题(16px)小 */
    color: var(--km-text-primary);
    transition: background-color 0.15s;
}

.header-menu-item:hover {
    background-color: var(--km-bg-hover);
}

.header-menu-item.danger {
    color: #d93025;
}

.header-menu-item.danger:hover {
    background-color: #fce8e6;
}

.header-menu-icon {
    width: 14px;
    height: 14px;
    fill: currentColor;
    flex-shrink: 0;
}

/* Banner Image in Header */
.header-banner {
    height: 48px;
    width: auto;
    object-fit: contain;
    margin: 0 auto; /* Center it */
    display: block;
}

.header-controls {
    flex-shrink: 0;
}

/* 侧边栏切换按钮位置微调 */
.sidebar-toggle-btn {
  top: 16px;
  left: 16px;
  color: var(--km-text-secondary);
  background: transparent;
  border: none;
  box-shadow: none;
}
.sidebar-toggle-btn:hover {
  background-color: var(--km-bg-hover);
  color: var(--km-text-primary);
}

/* 欢迎页容器 */
.welcome-view {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: calc(100vh - 60px); /* 减去 header 高度 */
}

/* Logo 和 标题 */
.logo-title {
  font-size: 42px;
  font-weight: 700;
  color: var(--km-text-primary);
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}

.welcome-subtitle {
  font-size: 16px;
  color: var(--km-text-secondary);
  margin-bottom: 48px;
  font-weight: 400;
}

/* 居中大搜索框 - Kimi 风格 */
.search-box-container {
  width: 100%;
  max-width: 760px; /* 稍微加宽 */
  background: #ffffff;
  border: 1px solid rgba(223, 225, 229, 0); /* 初始无边框或极淡 */
  border-radius: 32px; /* 更大的圆角 */
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08); /* 柔和的阴影 */
  padding: 10px 16px;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  margin-bottom: 48px;
  position: relative;
}

.search-box-container:focus-within,
.search-box-container:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  border-color: rgba(223, 225, 229, 0);
  background: #ffffff;
}

.prompt-area {
  display: flex;
  align-items: flex-end; /* 底部对齐，适应多行输入 */
  background: transparent;
  border: none;
  padding: 0;
  gap: 12px;
  width: 100%;
}

.prompt-input {
  flex: 1;
  border: none;
  font-size: 16px;
  line-height: 24px;
  padding: 12px 0;
  color: var(--km-text-primary);
  background: transparent;
  min-height: 48px; /* 确保有一定高度 */
  resize: none; /* 如果是 textarea */
}

.prompt-input::placeholder {
  color: #9aa0a6;
}

.prompt-input:focus {
  outline: none;
}

.file-upload-btn-inline {
  color: #5f6368;
  padding: 10px;
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 4px; /* 对齐底部 */
}

.file-upload-btn-inline:hover {
  background-color: rgba(0, 0, 0, 0.05);
  color: var(--km-text-primary);
}

.send-btn-inline {
  background-color: #e3e3e3; /* 默认浅灰 */
  color: #ffffff;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  cursor: not-allowed;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  margin-bottom: 6px; /* 对齐底部 */
}

/* 输入框有内容时激活发送按钮 (需要JS配合添加 .active 类，或者利用 placeholder-shown trick) */
.send-btn-inline:not(:disabled),
.prompt-input:not(:placeholder-shown) ~ .send-btn-inline,
.prompt-input:valid ~ .send-btn-inline {
  background-color: var(--km-primary); /* Kimi 蓝 */
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(0,0,0,0.2);
}

.send-btn-inline:not(:disabled):hover {
  background-color: var(--km-primary-hover);
  transform: scale(1.05);
}

.send-btn-inline::after {
  content: "";
  width: 16px;
  height: 16px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%23ffffff'%3E%3Cpath d='M2.01 21L23 12 2.01 3 2 10l15 2-15 2z'/%3E%3C/svg%3E");
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  transform: translateX(1px); /* 视觉修正 */
}

/* 推荐卡片优化 */
.related-content {
  display: flex;
  gap: 24px;
  width: 100%;
  justify-content: center;
  padding: 0 20px;
}

.content-card {
  flex: 1;
  max-width: 280px;
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: 16px;
  overflow: hidden;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
  display: flex;
  flex-direction: column;
}

.content-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.1);
  border-color: transparent;
}

.card-image {
  width: 100%;
  height: 140px;
  object-fit: cover;
  display: block;
  transition: transform 0.3s ease;
}

.content-card:hover .card-image {
  transform: scale(1.02);
}

.card-image-placeholder {
  /* 兼容旧代码，虽然已替换 */
  height: 140px;
  opacity: 1;
}

.card-footer {
  padding: 16px 20px;
  text-align: left; /* Kimi 风格通常左对齐或居中 */
  font-weight: 500;
  font-size: 15px;
  color: var(--km-text-primary);
  background: #ffffff;
  border-top: 1px solid rgba(0,0,0,0.04);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-footer::after {
  content: "→";
  font-family: monospace;
  opacity: 0;
  transform: translateX(-10px);
  transition: all 0.3s ease;
  color: var(--km-primary);
}

.content-card:hover .card-footer::after {
  opacity: 1;
  transform: translateX(0);
}

/* ==========================================================================
   Task 4: 对话界面 (Chat View) 优化
   ========================================================================== */

.chat-container {
  padding: 20px 0 40px; /* 底部留白给输入框 */
  background-color: #ffffff;
  margin: 0 auto;
  width: 100%;
  max-width: 100%;
}

.message {
  padding: 0 20px;
  margin-bottom: 24px;
}

/* 消息头像 */
.message-avatar {
  /* 假设 HTML 结构有头像，如果没有则忽略 */
  width: 32px;
  height: 32px;
  border-radius: 50%;
  margin-right: 12px;
}

/* 消息气泡 - 用户 */
.message.user .message-content {
  background-color: var(--km-bg-input); /* 浅灰背景，Kimi 风格 */
  color: var(--km-text-primary);
  border-radius: 20px;
  padding: 12px 20px;
  font-size: 15px;
  line-height: 1.6;
  max-width: 85%;
  margin-left: auto; /* 靠右 */
}

/* 消息气泡 - AI */
.message.assistant .message-content {
  background-color: transparent; /* AI 回复通常无背景，直接显示文字 */
  border: none;
  padding: 0 12px; /* 稍微留点内边距 */
  color: var(--km-text-primary);
  font-size: 15px;
  line-height: 1.7;
  max-width: 100%;
}

/* AI 回复中的 Markdown 样式 */
.message.assistant .message-content p {
  margin-bottom: 12px;
}
.message.assistant .message-content pre {
  background-color: #f6f8fa;
  border-radius: 8px;
  padding: 16px;
  border: 1px solid var(--km-border-light);
}

/* 底部输入框容器 */
.input-container {
  max-width: 800px;
  margin: 0 auto;
  width: 100%;
  background: #ffffff;
  border-top: none;
  padding: 16px 20px 24px;
  position: sticky;
  bottom: 0;
  z-index: 100;
}

/* 输入框本身 */
.input-container input[type="text"] {
  background-color: var(--km-bg-input);
  border: 1px solid transparent;
  border-radius: 24px;
  padding: 14px 20px;
  font-size: 15px;
  transition: all 0.2s;
  box-shadow: none;
}

.input-container input[type="text"]:focus {
  background-color: #ffffff;
  border-color: var(--km-border);
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

/* 发送按钮 */
.send-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  background-color: var(--km-bg-active);
  color: var(--km-text-secondary);
}

.send-btn:not(:disabled):hover {
  background-color: var(--km-primary);
  color: #ffffff;
}

/* 文件上传按钮 */
.file-upload-btn {
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  color: var(--km-text-secondary);
  font-size: 20px;
}
.file-upload-btn:hover {
  background-color: var(--km-bg-hover);
  border-radius: 50%;
}

/* 文件预览 */
.file-preview-container {
  background: transparent;
  border-top: none;
  padding: 0 20px 10px;
  max-width: 800px;
  margin: 0 auto;
}

.file-preview-item {
  background: #ffffff;
  border: 1px solid var(--km-border);
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

/* 登录提示条 */
.login-prompt {
  border-radius: 8px;
  background-color: var(--km-primary-light);
  color: var(--km-primary);
  border: 1px solid rgba(26,115,232,0.2);
}
.login-prompt .btn {
  background-color: var(--km-primary);
  color: white;
  border-radius: 16px;
}

/* 响应式调整 */
@media (max-width: 768px) {
  .welcome-view {
    padding: 20px;
    height: auto;
    display: block; /* 取消 flex 居中，防止键盘弹出遮挡 */
    padding-top: 60px;
  }
  
  .logo-title {
    font-size: 32px;
    text-align: center;
  }
  
  .welcome-subtitle {
    text-align: center;
    margin-bottom: 32px;
  }
  
  .related-content {
    flex-direction: column;
  }
  
  .content-card {
    max-width: 100%;
  }
  
  .chat-container {
    padding: 10px 0 100px;
  }
  
  .message.user .message-content {
    max-width: 90%;
  }
}