/* ======================== css/style.css ======================== */
/* ----- 全局重置与基础样式 ----- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;  /* 平滑滚动 */
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #ffffff;
    color: #1e2a3a;
    line-height: 1.5;
}

a {
    text-decoration: none;
    color: inherit;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ----- 头部导航栏 (sticky) ----- */
header {
    background-color: #ffffff;
    box-shadow: 0 1px 12px rgba(0, 0, 0, 0.04);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
    width: 100%;
}

.logo {
    font-size: 1.35rem;
    font-weight: 500;
    letter-spacing: 1px;
    background: linear-gradient(135deg, #1A2A3A 0%, #0f5e9e 100%);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    font-size: 1rem;
    font-weight: 500;
    color: #2c3e50;
    transition: color 0.25s ease;
    position: relative;
    cursor: pointer;
}

.nav-links a:hover {
    color: #0077cc;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 0;
    height: 2px;
    background: #0077cc;
    transition: width 0.25s;
}

.nav-links a:hover::after {
    width: 100%;
}

/* ----- Hero区域 (左文右图) ----- */
.hero {
    padding: 60px 0 40px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 56px;
}

.hero-text {
    flex: 1.1;
    padding-left: 20px;
    padding-right: 20px;
}

.hero-text h1 {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 1.2rem;
    color: #0b2b3b;
    letter-spacing: -0.3px;
    line-height: 1.3;
}

.hero-text p {
    font-size: 1rem;
    color: #2c3e50;
    margin-bottom: 1rem;
    text-align: justify;
    line-height: 1.6;
}

.hero-text p:last-of-type {
    margin-bottom: 1.5rem;
}

/* 轮播图区域 */
.hero-slider {
    flex: 1;
    position: relative;
    overflow: hidden;
    border-radius: 28px;
    box-shadow: 0 20px 35px -12px rgba(0, 0, 0, 0.2);
    aspect-ratio: 16 / 10;
    background: #f0f2f5;
}

.slider-track {
    display: flex;
    width: 100%;
    height: 100%;
    transition: transform 0.55s cubic-bezier(0.2, 0.9, 0.4, 1.1);
}

.slide {
    min-width: 100%;
    height: 100%;
}

.slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.slider-dots {
    position: absolute;
    bottom: 18px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 12px;
    z-index: 20;
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(4px);
    padding: 6px 12px;
    border-radius: 60px;
}

.dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.65);
    cursor: pointer;
    transition: all 0.2s ease;
}

.dot.active {
    background-color: #ffffff;
    transform: scale(1.25);
    box-shadow: 0 0 5px rgba(255,255,255,0.6);
}

/* 四个核心功能卡片 */
.features {
    padding: 48px 0 70px 0;
    background-color: #fbfcfd;
}

.section-title {
    text-align: center;
    font-size: 2rem;
    font-weight: 400;
    margin-bottom: 48px;
    color: #0f2b36;
    letter-spacing: -0.2px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
}

.feature-item {
    background: #ffffff;
    padding: 2rem 1.6rem;
    border-radius: 28px;
    box-shadow: 0 10px 25px -8px rgba(0, 0, 0, 0.05);
    transition: all 0.25s ease;
    border: 1px solid rgba(0, 0, 0, 0.02);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 24px 36px -12px rgba(0, 110, 230, 0.12);
    border-color: #e9edf2;
}

.feature-item h3 {
    font-size: 1.4rem;
    font-weight: 400;
    margin-bottom: 0.9rem;
    color: #0f2b36;
    line-height: 1.3;
}

.feature-item p {
    font-size: 0.95rem;
    color: #3a5468;
    line-height: 1.5;
    text-align: left;
}

/* 视频板块 - 黑底沉浸, 添加锚点偏移避免被导航栏遮挡 */
.video-showcase {
    background-color: #03080e;
    padding: 52px 0 64px 0;
    scroll-margin-top: 80px;
}

.video-container {
    max-width: 1140px;
    margin: 0 auto;
    border-radius: 28px;
    overflow: hidden;
    box-shadow: 0 25px 45px -12px rgba(0, 0, 0, 0.5);
    background: #000;
    transition: transform 0.2s;
}

.video-container video {
    width: 100%;
    display: block;
    outline: none;
}

.video-caption {
    text-align: center;
    margin-top: 1.5rem;
}

.video-caption p {
    color: #bfd7f5;
    font-size: 0.95rem;
    margin-bottom: 0.8rem;
}

.download-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #1e6fdf;
    color: white;
    padding: 8px 26px;
    border-radius: 40px;
    font-size: 0.85rem;
    font-weight: 500;
    transition: background 0.2s, transform 0.1s;
}

.download-link:hover {
    background: #0c57b3;
    transform: scale(0.98);
}

/* 三个背景图片卡片 */
.features-extended {
    padding: 70px 0;
    background: #ffffff;
}

.extended-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.extended-card {
    position: relative;
    border-radius: 32px;
    overflow: hidden;
    aspect-ratio: 16 / 10;
    display: flex;
    align-items: flex-end;
    justify-content: flex-start;
    transition: all 0.35s ease;
    box-shadow: 0 18px 30px -12px rgba(0, 0, 0, 0.2);
    cursor: default;
}

.extended-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 28px 38px -12px rgba(0, 0, 0, 0.3);
}

.extended-card:nth-child(1) {
    background: linear-gradient(0deg, rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.2)), url('../images/6.jpg');
    background-size: cover;
    background-position: center 30%;
}
.extended-card:nth-child(2) {
    background: linear-gradient(0deg, rgba(0, 0, 0, 0.45), rgba(0, 0, 0, 0.2)), url('../images/5.jpg');
    background-size: cover;
    background-position: center;
}
.extended-card:nth-child(3) {
    background: linear-gradient(0deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.15)), url('../images/7.jpg');
    background-size: cover;
    background-position: center;
}

.extended-card-content {
    width: 100%;
    padding: 28px 28px 24px 28px;
    background: linear-gradient(0deg, rgba(0, 0, 0, 0.85) 0%, rgba(0, 0, 0, 0.2) 100%);
    color: white;
    text-align: left;
    backdrop-filter: blur(1px);
}

.extended-card-content h3 {
    font-size: 1.3rem;
    font-weight: 500;
    margin-bottom: 8px;
    letter-spacing: -0.2px;
}

.extended-card-content p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.85);
    line-height: 1.4;
}

/* 联系方式区域 */
.contact {
    background-color: #f7fafc;
    padding: 56px 0;
    border-top: 1px solid #eef2f6;
    border-bottom: 1px solid #eef2f6;
}

.contact-simple h3 {
    font-size: 1.25rem;
    font-weight: 500;
    color: #0a2b38;
    margin-bottom: 1.5rem;
    letter-spacing: 0px;
    border-left: 4px solid #2c7da0;
    padding-left: 16px;
}

.contact-info-list {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    font-size: 1rem;
    color: #1f3c4c;
}

.contact-item {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 1rem;
}

.label {
    font-weight: 500;
    color: #1f4e6e;
    min-width: 88px;
}

.value {
    color: #2c5a74;
    word-break: break-word;
}

.contact-info-list a {
    color: #2c7da0;
    transition: color 0.2s;
    border-bottom: 1px dotted transparent;
}

.contact-info-list a:hover {
    color: #0f5b7a;
    border-bottom-color: #0f5b7a;
}

/* 页脚 */
footer {
    padding: 36px 0;
    text-align: center;
    background: #ffffff;
    color: #5e7e9a;
    font-size: 0.85rem;
}

.footer-icp-link {
    color: #5e7e9a;
    transition: color 0.2s;
}

.footer-icp-link:hover {
    color: #1e6fdf;
    text-decoration: underline;
}

/* 响应式断点 */
@media (max-width: 1100px) {
    .hero-text h1 { font-size: 1.2rem; }
    .feature-grid { gap: 24px; }
}

@media (max-width: 992px) {
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .extended-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
    .hero {
        gap: 40px;
        padding: 50px 0;
        text-align: left;
    }
    .hero-text h1 {
        font-size: 1.2rem;
        margin-top: 20px;
        text-align: left;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 20px;
    }
    .hero {
        flex-direction: column;
        text-align: center;
        gap: 32px;
    }
    .hero-text p {
        text-align: left;
    }
    .hero-text {
        padding: 0;
    }
    .hero-slider {
        width: 100%;
        aspect-ratio: 16/9;
    }
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    .extended-grid {
        grid-template-columns: 1fr;
    }
    .extended-card-content h3 {
        font-size: 1.2rem;
    }
    .section-title {
        font-size: 1.8rem;
        margin-bottom: 32px;
    }
    .contact-item {
        flex-direction: column;
        gap: 4px;
    }
    .label {
        min-width: auto;
    }
    .video-container {
        border-radius: 20px;
    }
    .video-showcase {
        scroll-margin-top: 70px;
    }
}