/* CSS 变量定义 */
:root {
    /* 主题色 */
    --primary-color: #FF6B6B;
    --secondary-color: #4ECDC4;
    --accent-yellow: #FFE66D;
    --accent-blue: #95E1D3;
    
    /* 中性色 */
    --bg-color: #F8F9FA;
    --card-bg: #FFFFFF;
    --text-primary: #2C3E50;
    --text-secondary: #7F8C8D;
    --border-color: #E9ECEF;
    
    /* 间距 */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    
    /* 阴影 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    
    /* 动画 */
    --transition-fast: 0.2s ease-out;
    --transition-normal: 0.3s ease-out;
    --transition-slow: 0.5s ease-out;
    
    /* 尺寸 */
    --header-height: 60px;
    --bottom-nav-height: 64px;
    --max-width: 768px;
}

/* 通用布局 */
#app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    max-width: var(--max-width);
    margin: 0 auto;
    background-color: var(--bg-color);
}

/* 顶部导航栏 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: linear-gradient(135deg, var(--primary-color), #FF8787);
    color: white;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-content {
    max-width: var(--max-width);
    margin: 0 auto;
    height: 100%;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 600;
}

.logo-icon {
    font-size: 1.5rem;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-4px); }
}

.logo-text {
    letter-spacing: 0.5px;
}

.settings-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: all var(--transition-fast);
}

.settings-btn:active {
    transform: scale(0.95);
    background: rgba(255, 255, 255, 0.3);
}

/* 主内容区域 */
.main-content {
    flex: 1;
    margin-top: var(--header-height);
    margin-bottom: var(--bottom-nav-height);
    overflow-y: auto;
}

/* 页面切换 */
.page {
    display: none;
    min-height: calc(100vh - var(--header-height) - var(--bottom-nav-height));
}

.page.active {
    display: block;
    animation: fadeIn var(--transition-normal);
}

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

/* 底部导航 */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--bottom-nav-height);
    background: var(--card-bg);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-around;
    align-items: center;
    z-index: 100;
    box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.05);
}

.nav-btn {
    flex: 1;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.nav-btn.active {
    color: var(--primary-color);
}

.nav-icon {
    font-size: 1.5rem;
}

.nav-label {
    font-size: 0.75rem;
}

.nav-btn:active {
    transform: scale(0.95);
}

/* Toast 提示 */
.toast {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%) translateY(-100px);
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-normal);
    z-index: 1000;
    max-width: 80%;
    text-align: center;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* 加载动画 */
.loading {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 999;
}

.loading.show {
    display: flex;
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 通用按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 500;
    transition: all var(--transition-fast);
    min-height: 44px;
    gap: var(--spacing-sm);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), #FF8787);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:active {
    transform: translateY(2px);
    box-shadow: none;
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-secondary:active {
    transform: translateY(2px);
    box-shadow: none;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
}

.btn-outline:active {
    background: var(--primary-color);
    color: white;
}

/* 通用卡片样式 */
.card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
}

.card:active {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* 响应式 */
@media (max-width: 768px) {
    :root {
        --header-height: 56px;
        --bottom-nav-height: 60px;
    }
}

/* 触控优化 */
@media (hover: none) {
    .btn:active,
    .card:active,
    .nav-btn:active,
    .settings-btn:active {
        transition-duration: 0.1s;
    }
}

/* 安全区域适配 (iPhone X 等) */
@supports (padding: max(0px)) {
    .header-content {
        padding-left: max(var(--spacing-md), env(safe-area-inset-left));
        padding-right: max(var(--spacing-md), env(safe-area-inset-right));
    }
    
    .bottom-nav {
        padding-bottom: env(safe-area-inset-bottom);
    }
}