/* 北方钢铁网 - 头部设计样式 */

/* ==================== Header Top ==================== */
.header-top {
    background: rgba(0, 0, 0, 0.3);
    padding: 0.8rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.header-top .header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

/* Logo 区域 */
.header-logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.header-logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 1px;
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-logo p {
    font-size: 0.85rem;
    opacity: 0.9;
    margin-top: 3px;
    color: rgba(255, 255, 255, 0.8);
}

/* 联系信息 */
.header-contact {
    display: flex;
    gap: 25px;
    align-items: center;
}

.contact-phone,
.contact-address {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
    transition: var(--transition);
}

.contact-phone:hover,
.contact-address:hover {
    opacity: 0.8;
}

.contact-phone i,
.contact-address i {
    color: var(--secondary-color);
    font-size: 1.1rem;
}

.phone-number {
    font-weight: 700;
    color: var(--secondary-color);
    font-size: 1.1rem;
}

/* ==================== Main Navigation ==================== */
.modern-nav {
    background: var(--white);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    position: relative;
}

.modern-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

/* Nav Logo */
.nav-logo {
    padding: 10px 0;
}

.nav-logo a {
    display: flex;
    flex-direction: column;
    transition: var(--transition);
}

.nav-logo a:hover {
    opacity: 0.8;
}

.nav-logo h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
    line-height: 1.2;
}

.nav-logo p {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-top: 2px;
}

/* Nav Menu */
.nav-menu {
    flex: 1;
    display: flex;
    justify-content: center;
}

.nav-menu > ul {
    display: flex;
    gap: 5px;
}

.nav-menu li {
    position: relative;
}

.nav-menu > ul > li > a {
    display: block;
    padding: 1rem 1.3rem;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
    border-radius: 4px;
    position: relative;
}

.nav-menu > ul > li > a:hover,
.nav-menu > ul > li > a.active {
    color: var(--accent-color);
    background: rgba(238, 150, 75, 0.08);
}

.nav-menu > ul > li > a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60%;
    height: 3px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
    border-radius: 2px;
}

/* 下拉菜单箭头 */
.nav-menu li.dropdown > a i {
    margin-left: 5px;
    font-size: 0.75rem;
    transition: var(--transition);
}

.nav-menu li.dropdown:hover > a i {
    transform: rotate(180deg);
}

/* Dropdown Menu */
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--white);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    border-radius: 8px;
    min-width: 220px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(15px);
    transition: all 0.3s ease;
    z-index: 1001;
    overflow: hidden;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -6px;
    left: 20px;
    width: 12px;
    height: 12px;
    background: var(--white);
    transform: rotate(45deg);
    border-left: 1px solid rgba(0, 0, 0, 0.05);
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.dropdown-menu li {
    border-bottom: 1px solid #f5f5f5;
}

.dropdown-menu li:last-child {
    border-bottom: none;
}

.dropdown-menu li a {
    padding: 0.9rem 1.3rem;
    font-size: 0.92rem;
    color: var(--text-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.dropdown-menu li a:hover {
    background: linear-gradient(90deg, rgba(238, 150, 75, 0.1), transparent);
    color: var(--accent-color);
    padding-left: 1.5rem;
}

.dropdown-menu li a i {
    font-size: 0.7rem;
    opacity: 0;
    transform: translateX(-10px);
    transition: var(--transition);
}

.dropdown-menu li a:hover i {
    opacity: 1;
    transform: translateX(0);
}

/* Nav Contact Button */
.nav-contact {
    padding: 10px 0;
}

.nav-contact .btn-call {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: var(--primary-color);
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
    box-shadow: 0 3px 10px rgba(244, 211, 94, 0.3);
}

.nav-contact .btn-call:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(244, 211, 94, 0.4);
}

.nav-contact .btn-call i {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

/* Mobile Toggle */
.mobile-toggle {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--primary-color);
    padding: 10px;
    transition: var(--transition);
}

.mobile-toggle:hover {
    color: var(--accent-color);
}

/* ==================== Mobile Navigation ==================== */
@media (max-width: 992px) {
    .nav-menu,
    .nav-contact {
        display: none;
    }
    
    .mobile-toggle {
        display: block;
    }
    
    .nav-logo h2 {
        font-size: 1.3rem;
    }
}

@media (max-width: 768px) {
    .header-top .header-container {
        flex-direction: column;
        text-align: center;
    }
    
    .header-logo {
        flex-direction: column;
        gap: 8px;
    }
    
    .header-logo h1 {
        font-size: 1.5rem;
    }
    
    .header-contact {
        flex-direction: column;
        gap: 10px;
        width: 100%;
    }
    
    .contact-phone,
    .contact-address {
        justify-content: center;
    }
    
    .modern-nav .container {
        padding: 0 15px;
    }
    
    .nav-logo h2 {
        font-size: 1.2rem;
    }
    
    .nav-logo p {
        font-size: 0.75rem;
    }
}

/* ==================== Sticky Header Animation ==================== */
.header.is-sticky {
    animation: slideDown 0.3s ease;
}

.header.is-sticky .header-top {
    display: none;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
    }
    to {
        transform: translateY(0);
    }
}

/* ==================== Header Variants ==================== */
/* 透明头部（用于首页 Hero 上方） */
.header-transparent {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    background: transparent;
}

.header-transparent .header-top {
    background: rgba(0, 0, 0, 0.5);
}

.header-transparent .modern-nav {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
}

/* 深色头部 */
.header-dark .modern-nav {
    background: var(--dark-color);
}

.header-dark .nav-menu li a {
    color: var(--white);
}

.header-dark .nav-menu li a:hover,
.header-dark .nav-menu li a.active {
    color: var(--secondary-color);
}

/* ==================== Mega Menu (可选扩展) ==================== */
.mega-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--white);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    padding: 30px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(15px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.dropdown:hover .mega-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.mega-menu-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
}

.mega-menu-column h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.1rem;
    border-bottom: 2px solid var(--secondary-color);
    padding-bottom: 8px;
    display: inline-block;
}

.mega-menu-column ul {
    list-style: none;
}

.mega-menu-column ul li {
    margin-bottom: 10px;
}

.mega-menu-column ul li a {
    color: var(--text-light);
    transition: var(--transition);
}

.mega-menu-column ul li a:hover {
    color: var(--accent-color);
    padding-left: 5px;
}

@media (max-width: 992px) {
    .mega-menu {
        position: static;
        box-shadow: none;
        padding: 15px;
        display: none;
    }
    
    .mega-menu-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .dropdown:hover .mega-menu {
        display: block;
        opacity: 1;
        visibility: visible;
        transform: none;
    }
}