/* 
 * 宝鸡果一诺金属材料有限公司 - 全局样式
 * 经典商务风 | 黑白灰渐变 | 阶梯式错落布局
 */

/* ========== CSS Reset & 基础设置 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.8;
    color: #333;
    background: linear-gradient(180deg, #f8f9fa 0%, #ffffff 50%, #f0f1f2 100%);
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 50px;
    position: relative;
    color: #1a1a1a;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, #333, #666, #333);
    border-radius: 2px;
}

/* ========== 顶部导航栏 ========== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    transition: all 0.4s ease;
}

.header.scrolled {
    background: rgba(20, 20, 20, 0.98);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

.header.scrolled .nav-link,
.header.scrolled .logo-text {
    color: #fff;
}

.header.scrolled .nav-link:hover {
    color: #ccc;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-img {
    width: 50px;
    height: 50px;
    object-fit: contain;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1a1a1a;
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
    gap: 35px;
}

.nav-link {
    font-size: 1rem;
    font-weight: 500;
    color: #333;
    position: relative;
    padding: 8px 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #333, #666);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 28px;
    height: 3px;
    background: #333;
    border-radius: 2px;
    transition: all 0.3s ease;
}

.header.scrolled .hamburger span {
    background: #fff;
}

/* ========== 页脚 ========== */
.footer {
    background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 50%, #1a1a1a 100%);
    color: #ccc;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    color: #fff;
    font-size: 1.2rem;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
}

.footer-section h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: #666;
}

.footer-section p,
.footer-section li {
    font-size: 0.95rem;
    line-height: 2;
    color: #aaa;
}

.footer-section a:hover {
    color: #fff;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid #333;
    font-size: 0.9rem;
    color: #888;
}

/* ========== 按钮样式 ========== */
.btn {
    display: inline-block;
    padding: 14px 35px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-primary {
    background: linear-gradient(135deg, #333 0%, #555 100%);
    color: #fff;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #555 0%, #333 100%);
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

.btn-secondary {
    background: transparent;
    color: #333;
    border: 2px solid #333;
}

.btn-secondary:hover {
    background: #333;
    color: #fff;
    transform: translateY(-3px);
}

/* ========== 卡片样式 ========== */
.card {
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.4s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.card-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
}

.card-content {
    padding: 25px;
}

.card-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: #1a1a1a;
}

.card-text {
    font-size: 0.95rem;
    color: #666;
    line-height: 1.7;
    margin-bottom: 15px;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: #999;
}

/* ========== 动画效果 ========== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 响应式设计 ========== */
@media (max-width: 1024px) {
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: rgba(20, 20, 20, 0.98);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: 50px;
        gap: 30px;
        transition: left 0.4s ease;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-link {
        color: #fff;
        font-size: 1.2rem;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(6px, 6px);
    }
    
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(6px, -6px);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .section {
        padding: 50px 0;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
}

/* ========== 阶梯式错落布局 ========== */
.stagger-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.stagger-section.reverse {
    direction: rtl;
}

.stagger-section.reverse > * {
    direction: ltr;
}

.stagger-content {
    padding: 40px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.stagger-image {
    width: 100%;
    height: 400px;
    object-fit: cover;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
}

@media (max-width: 768px) {
    .stagger-section,
    .stagger-section.reverse {
        grid-template-columns: 1fr;
        direction: ltr;
    }
    
    .stagger-image {
        height: 250px;
    }
}