/* ==================== 色彩系统 - 白底黑字 ==================== */
:root {
    /* 品牌色 */
    --brand-primary: #ff7b00;
    --brand-secondary: #ff5252;
    --brand-tertiary: #ffb300;
    --brand-gradient: linear-gradient(135deg, #ff7b00 0%, #ff5252 100%);

    /* 边框色彩 */
    --border-orange: #ff7b00;
    --border-yellow: #ffb300;
    --border-green: #22c55e;
    --border-blue: #3b82f6;
    --border-purple: #8b5cf6;
    --border-pink: #ec4899;

    /* 背景色 */
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --bg-orange-light: #fff7ed;
    --bg-yellow-light: #fefce8;
    --bg-green-light: #f0fdf4;
    --bg-blue-light: #eff6ff;

    /* 文字色 */
    --text-primary: #1f2937;
    --text-secondary: #4b5563;
    --text-tertiary: #6b7280;
    --text-white: #ffffff;

    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;
}

/* ==================== 基础重置 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

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);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ==================== 头部导航 ==================== */
.site-header {
    background: var(--bg-primary);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 3px solid var(--border-orange);
}

.header-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 32px;
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    transition: opacity 0.3s ease;
    flex-shrink: 0;
}

.header-left:hover {
    opacity: 0.9;
}

.logo {
    width: 44px;
    height: 44px;
    object-fit: contain;
    display: block;
}

.brand-name {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: 0.2px;
    white-space: nowrap;
}

.header-nav {
    display: flex;
    gap: 6px;
    align-items: center;
}

.header-actions {
    display: flex;
    gap: 8px;
    align-items: center;
    flex-shrink: 0;
}

.action-btn {
    padding: 8px 16px;
    border: 2px solid var(--border-orange);
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    transition: all 0.3s ease;
    background: var(--bg-primary);
    white-space: nowrap;
}

.action-btn:hover {
    background: var(--bg-orange-light);
    border-color: var(--brand-primary);
    color: var(--brand-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.action-btn.primary-action {
    background: var(--brand-gradient);
    color: white;
    border-color: transparent;
}

.action-btn.primary-action:hover {
    background: linear-gradient(135deg, #ff5252 0%, #ff7b00 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.nav-item {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 14px;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.nav-item:hover {
    background: var(--bg-orange-light);
    color: var(--text-primary);
    border: 1px solid var(--border-orange);
}

.nav-item.active {
    background: var(--bg-orange-light);
    color: var(--brand-primary);
    border: 1px solid var(--border-orange);
    font-weight: 600;
}

/* ==================== 下拉菜单 ==================== */
.dropdown {
    position: relative;
}

.dropdown .nav-link {
    display: flex;
    align-items: center;
    gap: 4px;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 14px;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.dropdown .nav-link:hover {
    background: var(--bg-orange-light);
    color: var(--text-primary);
    border: 1px solid var(--border-orange);
}

.dropdown .nav-link.active {
    background: var(--bg-orange-light);
    color: var(--brand-primary);
    border: 1px solid var(--border-orange);
    font-weight: 600;
}

.dropdown-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    background: var(--bg-primary);
    border: 2px solid var(--border-orange);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    padding: 8px 0;
    z-index: 1001;
    margin-top: 4px;
}

.dropdown.show > .dropdown-menu {
    display: block;
}

.dropdown-item-link {
    display: block;
    padding: 12px 20px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.2s ease;
}

.dropdown-item-link:hover {
    background: var(--bg-orange-light);
    color: var(--brand-primary);
}

/* 三级菜单 */
.dropdown-item {
    position: relative;
}

.dropdown-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.2s ease;
}

.dropdown-item:hover > .dropdown-title {
    background: var(--bg-orange-light);
    color: var(--brand-primary);
}

.dropdown-submenu {
    display: none;
    position: absolute;
    left: 100%;
    top: 0;
    min-width: 200px;
    background: var(--bg-primary);
    border: 2px solid var(--border-yellow);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    padding: 8px 0;
    z-index: 1002;
    margin-left: 4px;
}

.dropdown-item.show > .dropdown-submenu {
    display: block;
}

.submenu-item {
    display: block;
    padding: 10px 18px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 13px;
    transition: all 0.2s ease;
}

.submenu-item:hover {
    background: var(--bg-yellow-light);
    color: var(--brand-primary);
}

.menu-toggle {
    display: none;
    background: none;
    border: 2px solid var(--border-orange);
    color: var(--brand-primary);
    font-size: 22px;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
}

.menu-toggle:hover {
    background: var(--bg-orange-light);
}

/* ==================== 底部 ==================== */
.site-footer {
    background: var(--bg-secondary);
    color: var(--text-tertiary);
    padding: 24px 0;
    border-top: 2px solid var(--border-orange);
    margin-top: auto;
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 32px;
    text-align: center;
    font-size: 14px;
}

/* ==================== 响应式 ==================== */
/* 平板和桌面 - 中等屏幕也显示汉堡菜单 */
@media (max-width: 1200px) {
    .menu-toggle {
        display: block;
    }

    .header-actions {
        display: none;
    }

    .header-nav {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: 16px;
        gap: 2px;
        box-shadow: var(--shadow-lg);
        border: 2px solid var(--border-orange);
        border-top: none;
    }

    .header-nav.show {
        display: flex;
    }

    .nav-item,
    .dropdown .nav-link {
        width: 100%;
        padding: 10px 16px;
    }

    .dropdown-menu {
        position: static;
        box-shadow: none;
        border: none;
        border-left: 3px solid var(--border-orange);
        margin-top: 4px;
        margin-left: 8px;
    }

    .dropdown.show > .dropdown-menu {
        display: block;
    }

    .dropdown-submenu {
        position: static;
        box-shadow: none;
        border: none;
        border-left: 2px solid var(--border-yellow);
        margin-left: 8px;
        margin-top: 2px;
    }

    .dropdown-item.show > .dropdown-submenu {
        display: block;
    }
}

@media (max-width: 768px) {
    .header-container {
        flex-wrap: wrap;
    }

    .header-nav {
        display: none;
        position: absolute;
        top: 68px;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: 18px;
        gap: 4px;
        box-shadow: var(--shadow-lg);
        border: 2px solid var(--border-orange);
        border-top: none;
    }

    .header-nav.show {
        display: flex;
    }

    .header-actions {
        display: none;
        flex-direction: column;
        width: 100%;
        padding: 12px 0;
        border-top: 2px solid var(--bg-tertiary);
        margin-top: 8px;
    }

    .header-actions.show {
        display: flex;
    }

    .action-btn {
        width: 100%;
        text-align: center;
        padding: 12px 20px;
    }

    .nav-item {
        width: 100%;
        text-align: center;
        padding: 14px;
    }

    /* 移动端下拉菜单 */
    .dropdown-menu {
        position: static;
        display: none;
        width: 100%;
        min-width: auto;
        box-shadow: none;
        border: 1px solid var(--border-yellow);
        margin-top: 8px;
    }

    .dropdown.show > .dropdown-menu {
        display: block;
    }

    .dropdown-item-link {
        padding: 12px;
        font-size: 14px;
        border-bottom: 1px solid var(--bg-tertiary);
    }

    .dropdown-item-link:last-child {
        border-bottom: none;
    }

    /* 移动端三级菜单 */
    .dropdown-submenu {
        position: static;
        display: none;
        width: 100%;
        min-width: auto;
        box-shadow: none;
        border: 1px solid var(--border-green);
        border-left: 3px solid var(--border-green);
        margin: 4px 0 0 0;
        padding-left: 16px;
    }

    .dropdown-item.show > .dropdown-submenu {
        display: block;
    }

    .submenu-item {
        padding: 10px 12px;
        font-size: 13px;
        border-bottom: 1px solid var(--bg-tertiary);
    }

    .submenu-item:last-child {
        border-bottom: none;
    }

    .menu-toggle {
        display: block;
    }
}