/* 全局样式 */
body {
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, #001f3f, #0074d9);
    color: #ffffff;
    line-height: 1.6;
}

/* 导航栏 */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 40px;
    background: rgba(0, 31, 63, 0.8);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.navbar .logo {
    font-size: 24px;
    font-weight: bold;
}

.navbar ul {
    list-style: none;
    display: flex;
    margin: 0;
}

.navbar ul li {
    margin-left: 20px;
}

.navbar ul li a {
    color: #ffffff;
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s ease;
}

.navbar ul li a:hover {
    color: #ffdc00;
}

/* 英雄区域 */
.hero {
    height: 100vh;
    background: url('https://images.gptkong.com/demo/sample1.png') center/cover no-repeat;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 0 20px;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
    color: #ffffff;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.hero p {
    font-size: 20px;
    max-width: 600px;
    margin-bottom: 30px;
    color: #dcdcdc;
}

.hero .cta-button {
    background-color: #ffdc00;
    color: #001f3f;
    padding: 15px 30px;
    border: none;
    border-radius: 25px;
    font-size: 18px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.hero .cta-button:hover {
    background-color: #e0b800;
    transform: scale(1.05);
}

/* 主体内容 */
.main-content {
    padding: 100px 40px 60px;
    background: linear-gradient(135deg, #002952, #0056b3);
}

.section {
    margin-bottom: 60px;
}

.section h2 {
    font-size: 32px;
    margin-bottom: 20px;
    text-align: center;
    color: #ffffff;
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.card {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 8px 16px rgba(0,0,0,0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: scale(1.05);
    box-shadow: 0 12px 24px rgba(0,0,0,0.4);
}

.card img {
    width: 100%;
    border-radius: 10px;
    margin-bottom: 15px;
}

.card h3 {
    font-size: 24px;
    margin-bottom: 10px;
    color: #ffdc00;
}

.card p {
    font-size: 16px;
    color: #dcdcdc;
    margin-bottom: 20px;
}

.card .buttons {
    display: flex;
    justify-content: flex-end;
}

.card .buttons a {
    text-decoration: none;
    background-color: #0074d9;
    color: #ffffff;
    padding: 10px 15px;
    border-radius: 5px;
    font-size: 14px;
    transition: background-color 0.3s ease;
    margin-left: 10px;
}

.card .buttons a:hover {
    background-color: #0056a3;
}

/* 示例文章展示 */
.example-article {
    background: rgba(255, 255, 255, 0.05);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.example-article h2 {
    font-size: 28px;
    margin-bottom: 15px;
    color: #ffffff;
}

.example-article p {
    font-size: 16px;
    color: #dcdcdc;
    margin-bottom: 15px;
}

.example-article pre {
    background: #001f3f;
    padding: 10px;
    border-radius: 5px;
    overflow-x: auto;
    color: #ffdc00;
    font-family: 'Courier New', Courier, monospace;
}

.example-article code {
    font-family: 'Courier New', Courier, monospace;
    color: #ffdc00;
}

/* 响应式设计 */
@media (max-width: 1440px) {
    .navbar {
        padding: 15px 30px;
    }

    .hero h1 {
        font-size: 40px;
    }

    .hero p {
        font-size: 18px;
    }

    .hero .cta-button {
        padding: 12px 25px;
        font-size: 16px;
    }

    .main-content {
        padding: 80px 30px 50px;
    }

    .section h2 {
        font-size: 28px;
    }
}

@media (max-width: 1200px) {
    .navbar {
        padding: 10px 20px;
    }

    .hero h1 {
        font-size: 36px;
    }

    .hero p {
        font-size: 16px;
    }

    .hero .cta-button {
        padding: 10px 20px;
        font-size: 16px;
    }

    .main-content {
        padding: 60px 20px 40px;
    }

    .section h2 {
        font-size: 24px;
    }
}

@media (max-width: 1024px) {
    .cards {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }

    .example-article {
        padding: 25px;
    }
}

@media (max-width: 768px) {
    .navbar ul {
        flex-direction: column;
        display: none;
    }

    .navbar ul.active {
        display: flex;
    }

    .navbar .menu-toggle {
        display: block;
        cursor: pointer;
        color: #ffffff;
        font-size: 24px;
    }

    .hero h1 {
        font-size: 32px;
    }

    .hero p {
        font-size: 14px;
    }

    .cards {
        grid-template-columns: 1fr;
    }

    .main-content {
        padding: 50px 15px 30px;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: 8px 15px;
    }

    .hero h1 {
        font-size: 28px;
    }

    .hero p {
        font-size: 12px;
    }

    .hero .cta-button {
        padding: 8px 15px;
        font-size: 14px;
    }

    .section h2 {
        font-size: 22px;
    }

    .card h3 {
        font-size: 20px;
    }

    .card p {
        font-size: 14px;
    }

    .card .buttons a {
        padding: 8px 12px;
        font-size: 12px;
    }

    .example-article h2 {
        font-size: 24px;
    }

    .example-article p, .example-article pre {
        font-size: 14px;
    }
}

@media (max-width: 320px) {
    .hero h1 {
        font-size: 24px;
    }

    .hero p {
        font-size: 10px;
    }

    .hero .cta-button {
        padding: 6px 10px;
        font-size: 12px;
    }

    .section h2 {
        font-size: 20px;
    }

    .card h3 {
        font-size: 18px;
    }

    .card p {
        font-size: 12px;
    }

    .card .buttons a {
        padding: 6px 10px;
        font-size: 10px;
    }

    .example-article h2 {
        font-size: 20px;
    }

    .example-article p, .example-article pre {
        font-size: 12px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.page-transition {
    animation: fadeIn 1s ease-in-out;
}

/* 其他元素 */
footer {
    background: rgba(0, 31, 63, 0.9);
    color: #dcdcdc;
    text-align: center;
    padding: 20px;
    font-size: 14px;
}

footer a {
    color: #ffdc00;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}