/* ==========================================
   头部导航样式 - Header Styles
   ========================================== */

.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: var(--color-white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    transition: all var(--transition-normal);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
}

/* Logo */
.logo a {
    font-size: 24px;
    font-weight: 700;
    color: var(--color-primary);
    font-family: var(--font-heading);
    transition: color var(--transition-fast);
}

.logo a:hover {
    color: var(--color-secondary);
}

/* 导航 */
.nav {
    display: flex;
    align-items: center;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--color-dark);
    font-weight: 500;
    font-size: 15px;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 6px;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--color-primary);
    background: var(--color-light-gray);
}

.nav-link.active {
    color: var(--color-primary);
    font-weight: 600;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 3px;
    background: var(--color-primary);
    border-radius: 2px;
}

/* CTA 按钮样式的导航链接 */
.nav-link.nav-cta {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: var(--color-white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 6px;
}

.nav-link.nav-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
    color: var(--color-white);
}

.nav-link.nav-cta.active::after {
    display: none;
}

/* 汉堡菜单图标 */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.hamburger span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--color-dark);
    border-radius: 2px;
    transition: all var(--transition-normal);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* 响应式设计 - 平板和移动端 */
@media (max-width: 1024px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 60px;
        right: -100%;
        width: 280px;
        height: calc(100vh - 60px);
        background: var(--color-white);
        flex-direction: column;
        align-items: flex-start;
        padding: var(--spacing-lg);
        gap: var(--spacing-sm);
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
        transition: right var(--transition-normal);
        overflow-y: auto;
    }
    
    .nav-menu.active {
        right: 0;
    }
    
    .nav-link {
        width: 100%;
        padding: var(--spacing-sm);
    }
    
    .nav-link.active::after {
        left: var(--spacing-sm);
        transform: translateX(0);
    }
    
    .nav-link.nav-cta {
        text-align: center;
        margin-top: var(--spacing-sm);
    }
}

/* 滚动时的头部样式 */
.header.scrolled {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}