:root {
    --primary-color: #4a6fa5;
    --secondary-color: #166d67;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    color: #333;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.container {
    width: 85%;
    max-width: 1200px;
    margin: 0 auto;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
}

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

.nav-links a {
    color: white;
    text-decoration: none;
    margin-left: 1.5rem;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.nav-links a:hover {
    background-color: rgba(255,255,255,0.2);
}

/* 下拉菜单样式 */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: white;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
    border-radius: 4px;
}

.dropdown-content a {
    color: var(--dark-color);
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    margin-left: 0;
}

.dropdown-content a:hover {
    background-color: #f1f1f1;
}

.dropdown:hover .dropdown-content {
    display: block;
}

.btn {
    display: inline-block;
    background-color: var(--secondary-color);
    color: white;
    padding: 0.6rem 1.2rem;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #0e524d;
}

.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 3rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
}

section {
    padding: 3rem 0;
}

h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background-color: var(--light-color);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.feature-card h3 {
    color: var(--secondary-color);
    margin-top: 0;
}

.how-to-use {
    background-color: var(--light-color);
}

.steps {
    max-width: 800px;
    margin: 0 auto;
}

.step {
    margin-bottom: 1.5rem;
    padding-left: 2rem;
    position: relative;
}

.step:before {
    content: counter(step);
    counter-increment: step;
    position: absolute;
    left: 0;
    top: 0;
    background-color: var(--primary-color);
    color: white;
    width: 1.8rem;
    height: 1.8rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

footer {
    background-color: var(--dark-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 2rem;
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .container {
        width: 90%;
    }
}