/* ===== CSS 变量 ===== */
:root {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-sidebar: #0f0f23;
    --bg-card: #1e1e3a;
    --bg-input: #2a2a4a;
    --bg-hover: #2a2a4a;
    --border-color: #2a2a4a;
    --text-primary: #e8e8f0;
    --text-secondary: #a0a0b8;
    --text-muted: #6a6a8a;
    --accent-primary: #6c63ff;
    --accent-secondary: #4ecdc4;
    --accent-gradient: linear-gradient(135deg, #6c63ff, #4ecdc4);
    --success: #4ecdc4;
    --warning: #ffd93d;
    --error: #ff6b6b;
    --sidebar-width: 260px;
    --topbar-height: 56px;
    --border-radius: 12px;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

/* ===== 全局样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* ===== 左侧导航栏 ===== */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease, width 0.3s ease;
    z-index: 100;
    flex-shrink: 0;
}

.sidebar.collapsed {
    transform: translateX(-100%);
    width: 0;
}

.sidebar-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--accent-primary);
}

.logo-text {
    font-size: 18px;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.new-chat-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 12px 16px;
    padding: 10px 16px;
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s ease;
    width: calc(100% - 32px);
    justify-content: center;
}

.new-chat-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(108, 99, 255, 0.3);
}

/* 导航菜单 */
.nav-menu {
    flex: 1;
    overflow-y: auto;
    padding: 8px 0;
}

.nav-section {
    padding: 0 8px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    margin: 2px 0;
    border-radius: 8px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 14px;
    transition: all 0.2s ease;
    position: relative;
}

.nav-item:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.nav-item.active {
    background: rgba(108, 99, 255, 0.15);
    color: var(--accent-primary);
}

.nav-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 20px;
    background: var(--accent-primary);
    border-radius: 0 3px 3px 0;
}

/* 历史对话 */
.history-section {
    border-top: 1px solid var(--border-color);
    padding: 12px 8px;
    max-height: 200px;
    overflow-y: auto;
}

.history-header {
    padding: 0 14px 8px;
    font-size: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.history-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 14px;
    border-radius: 6px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 13px;
    transition: all 0.2s ease;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.history-item:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

/* 用户区域 */
.sidebar-footer {
    padding: 12px 16px;
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
}

.avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
    color: white;
}

.settings-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    transition: all 0.2s ease;
}

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

/* ===== 主内容区域 ===== */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    position: relative;
}

/* 顶部模型切换栏 */
.top-bar {
    height: var(--topbar-height);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    padding: 0 16px;
    gap: 12px;
    overflow-x: auto;
    flex-shrink: 0;
}

.top-bar::-webkit-scrollbar {
    height: 0;
}

.sidebar-toggle {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.sidebar-toggle:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.model-tabs {
    display: flex;
    gap: 6px;
    flex-wrap: nowrap;
}

.model-tab {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 7px 14px;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 13px;
    white-space: nowrap;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.model-tab:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.model-tab.active {
    background: rgba(108, 99, 255, 0.2);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.model-icon {
    font-size: 16px;
}

/* ===== 聊天区域 ===== */
.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
}

.chat-container::-webkit-scrollbar {
    width: 6px;
}

.chat-container::-webkit-scrollbar-track {
    background: transparent;
}

.chat-container::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

/* 欢迎界面 */
.welcome-screen {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    text-align: center;
}

.welcome-icon {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: rgba(108, 99, 255, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(108, 99, 255, 0.3); }
    50% { box-shadow: 0 0 0 20px rgba(108, 99, 255, 0); }
}

.welcome-svg {
    color: var(--accent-primary);
}

.welcome-screen h1 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 8px;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-subtitle {
    color: var(--text-muted);
    font-size: 15px;
    margin-bottom: 32px;
}

/* 快捷功能按钮 */
.quick-actions {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    max-width: 500px;
    width: 100%;
}

.quick-action-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 16px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 13px;
    transition: all 0.2s ease;
}

.quick-action-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(108, 99, 255, 0.15);
}

.quick-action-btn svg {
    transition: all 0.2s ease;
}

.quick-action-btn:hover svg {
    color: var(--accent-primary);
}

/* 消息列表 */
.messages-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    padding-bottom: 20px;
}

.message {
    display: flex;
    gap: 12px;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.message.user {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background: var(--accent-gradient);
    color: white;
}

.message.assistant .message-avatar {
    background: rgba(78, 205, 196, 0.2);
    color: var(--accent-secondary);
}

.message-content {
    max-width: 75%;
    padding: 12px 16px;
    border-radius: 16px;
    font-size: 14px;
    line-height: 1.6;
}

.message.user .message-content {
    background: var(--accent-gradient);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.assistant .message-content {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-bottom-left-radius: 4px;
}

.message-content pre {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    padding: 12px;
    overflow-x: auto;
    margin: 8px 0;
    font-size: 13px;
}

.message-content code {
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 13px;
}

.message-content p {
    margin: 4px 0;
}

.message-content ul, .message-content ol {
    margin: 8px 0;
    padding-left: 20px;
}

/* 打字动画 */
.typing-indicator {
    display: flex;
    gap: 4px;
    padding: 4px 0;
}

.typing-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--text-muted);
    animation: typingDot 1.4s ease-in-out infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingDot {
    0%, 60%, 100% { transform: translateY(0); opacity: 0.4; }
    30% { transform: translateY(-6px); opacity: 1; }
}

/* ===== 输入区域 ===== */
.input-area {
    padding: 16px 20px;
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
    flex-shrink: 0;
}

.input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: 8px;
    max-width: 800px;
    margin: 0 auto;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 8px 12px;
    transition: border-color 0.2s ease;
}

.input-wrapper:focus-within {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(108, 99, 255, 0.1);
}

.input-action-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    transition: all 0.2s ease;
}

.input-action-btn:hover {
    color: var(--accent-primary);
    background: rgba(108, 99, 255, 0.1);
}

.message-input {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.5;
    resize: none;
    outline: none;
    max-height: 120px;
    font-family: inherit;
}

.message-input::placeholder {
    color: var(--text-muted);
}

.send-btn {
    background: var(--accent-primary);
    border: none;
    color: white;
    cursor: pointer;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
    background: #5a52e0;
    transform: scale(1.05);
}

.send-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.input-disclaimer {
    text-align: center;
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 8px;
}

/* ===== 登录/注册 ===== */
.auth-modal {
    max-width: 400px;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group label {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

.form-group input {
    padding: 10px 14px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.2s ease;
}

.form-group input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(108, 99, 255, 0.1);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.auth-submit-btn {
    padding: 12px;
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 4px;
}

.auth-submit-btn:hover:not(:disabled) {
    opacity: 0.9;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(108, 99, 255, 0.3);
}

.auth-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.auth-error {
    padding: 10px 14px;
    background: rgba(255, 107, 107, 0.1);
    border: 1px solid rgba(255, 107, 107, 0.3);
    border-radius: 8px;
    color: var(--error);
    font-size: 13px;
    text-align: center;
}

.auth-switch {
    text-align: center;
    margin-top: 16px;
    font-size: 13px;
    color: var(--text-muted);
}

.auth-switch a {
    color: var(--accent-primary);
    text-decoration: none;
    margin-left: 4px;
    font-weight: 500;
}

.auth-switch a:hover {
    text-decoration: underline;
}

/* ===== 模拟标签 ===== */
.model-tab.mock {
    opacity: 0.6;
}

.model-tab.mock:hover {
    opacity: 0.8;
}

.mock-badge {
    font-size: 10px;
    padding: 1px 6px;
    border-radius: 8px;
    background: rgba(255, 217, 61, 0.2);
    color: var(--warning);
    font-weight: 500;
}

/* ===== 弹窗 ===== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}

.modal {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 480px;
    box-shadow: var(--shadow);
    animation: modalIn 0.2s ease;
}

@keyframes modalIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 16px;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 24px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 4px;
    transition: all 0.2s ease;
}

.modal-close:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.modal-body {
    padding: 24px 20px;
}

.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 32px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-muted);
}

.upload-zone:hover {
    border-color: var(--accent-primary);
    background: rgba(108, 99, 255, 0.05);
}

.upload-hint {
    font-size: 12px;
    margin-top: 4px;
}

.upload-list {
    margin-top: 16px;
}

.upload-file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 12px;
    background: var(--bg-card);
    border-radius: 8px;
    margin-bottom: 8px;
    font-size: 13px;
}

.upload-file-item .remove-file {
    background: none;
    border: none;
    color: var(--error);
    cursor: pointer;
    font-size: 16px;
}

/* ===== sidebar user logout ===== */
#sidebarUserInfo {
    cursor: pointer;
}

#sidebarUserInfo:hover .avatar {
    opacity: 0.8;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        bottom: 0;
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .sidebar-overlay {
        display: none;
        position: fixed;
        inset: 0;
        background: rgba(0, 0, 0, 0.5);
        z-index: 99;
    }

    .sidebar-overlay.active {
        display: block;
    }

    .quick-actions {
        grid-template-columns: repeat(2, 1fr);
    }

    .model-tab span:last-child {
        display: none;
    }

    .model-tab {
        padding: 7px 10px;
    }

    .message-content {
        max-width: 85%;
    }
}