* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: '微软雅黑', sans-serif;
}

body {
    background: url('../../../background.png') no-repeat center center fixed;
    background-size: cover;
    min-height: 100vh;
}

h1 {
    text-align: center;
    color: white;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    font-size: 3.5em;
    margin-bottom: 30px;
    animation: fadeInUp 1s ease;
}

p {
    font-size: 1.2em;
    line-height: 1.6;
    animation: fadeIn 1.5s ease;
}

.content {
    padding: 100px 10%;
    color: #2c3e50;
}

.content-block {
    background: white;
    width: 85%;
    margin: 20px auto;
    border-radius: 8px;
    box-shadow: 0 3px 15px rgba(0,0,0,0.1);
    transition: all 0.3s;
    overflow: hidden;
}

.content-block:hover {
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.content-header {
    padding: 20px 30px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.content-header::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-top: 8px solid #3498db;
    transition: transform 0.3s;
}

.content-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    padding: 0 30px;
}

.content-body p {
    margin-bottom: 25px;
    line-height: 1.8;
    color: #666;
}

.content-body.active {
    max-height: 500px;
    padding: 20px 30px;
}

.content-header.active::after {
    transform: rotate(180deg);
}

.action-button {
    display: inline-block;
    padding: 10px 25px;
    background-color: #3498db;
    color: white !important;
    border-radius: 5px;
    text-decoration: none;
    transition: background 0.3s;
    margin-top: 15px;
}

.action-button:hover {
    background-color: #2980b9;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 50px;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(5px);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: relative;
}

.logo img {
    height: 40px;
    max-width: 180px;
    transition: transform 0.3s;
}

.logo:hover img {
    transform: scale(1.05);
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links li {
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: #2c3e50;
    font-weight: 500;
    padding: 10px 15px;
    border-radius: 5px;
    transition: all 0.3s;
    position: relative;
}

.nav-links a::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: #3498db;
    transition: width 0.3s;
}

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

.nav-links a:hover {
    color: #3498db;
}

.content {
    padding: 100px 20%;
    color: #7e7e7e;
    text-align: center;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.back-button {
    position: absolute;
    left: 50px;
    top: 90px;
    display: flex;
    align-items: center;
    color: #3498db;
    text-decoration: none;
    font-weight: 500;
    padding: 8px 15px;
    border-radius: 20px;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(2px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    z-index: 100;
}

.back-button::before {
    content: '';
    display: block;
    width: 12px;
    height: 12px;
    border-left: 2px solid #3498db;
    border-bottom: 2px solid #3498db;
    transform: rotate(45deg);
    margin-right: 8px;
    transition: all 0.3s;
}

.back-button:hover {
    transform: translateX(-5px);
    background: rgba(255,255,255,1);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.back-button:hover::before {
    border-color: #2980b9;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 768px) {
    .content-block {
        width: 95%;
    }

    .content-header {
        padding: 15px 20px;
    }

    .content-body p {
        font-size: 0.95em;
    }
}

@media (max-width: 768px) {
    .back-button {
        left: 20px;
        top: 70px;
        padding: 6px 12px;
        font-size: 14px;
    }
    
    .back-button::before {
        width: 10px;
        height: 10px;
        margin-right: 6px;
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: 10px 20px;
        flex-direction: column;
    }

    .logo img {
        height: 35px;
    }

    .nav-links {
        margin-top: 15px;
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }

    .content {
        padding: 50px 10%;
    }

    h1 {
        font-size: 2.5em;
    }
}