:root {
    --primary-blue: #2c5aa0;
    --secondary-blue: #4a90e2;
    --accent-green: #27ae60;
    /*--light-blue: #e8f4f8;*/
    --light-blue: #e8f4f8;
    --white: #ffffff;
    --text-dark: #333333;
    --text-light: #666666;
    --border-color: #e1e1e1;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --max-width: 1200px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--white);
}

.main-header {
    background-color: var(--white);
    border-bottom: 2px solid var(--light-blue);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.main-nav {
    padding: 1rem 2rem;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo {
    width: 50px;
    height: 50px;
}

.site-title {
    color: var(--primary-blue);
    font-size: 1.5rem;
    font-weight: 600;
}

.nav-controls {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.language-selector {
    display: flex;
    gap: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.25rem;
    background-color: var(--light-blue);
}

.lang-btn {
    padding: 0.5rem 1rem;
    border: none;
    background-color: transparent;
    color: var(--text-dark);
    cursor: pointer;
    border-radius: calc(var(--border-radius) - 2px);
    font-weight: 500;
    transition: all 0.3s ease;
}

.lang-btn.active {
    background-color: var(--primary-blue);
    color: var(--white);
}

.lang-btn:hover {
    background-color: var(--secondary-blue);
    color: var(--white);
}

.game-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--accent-green);
    background-color: var(--accent-green);
    color: var(--white);
    cursor: pointer;
    border-radius: var(--border-radius);
    font-weight: 500;
    font-size: 0.9rem;
    width: 9rem;
    height: 2.5rem;
    transition: all 0.3s ease;
}

.game-btn:hover {
    background-color: #219a52;
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.main-content {
    min-height: calc(100vh - 140px);
}

.hero-section {
    background: url("../images/hero-background.png") center/cover no-repeat;
    color: var(--white);
    padding: 4rem 2rem;
    text-align: center;
    min-height: 280px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.hero-section::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.2);
    z-index: 1;
}

.hero-content {
    max-width: var(--max-width);
    margin: 0 auto;
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.2rem;
    font-weight: 300;
    opacity: 1.0;
    max-width: 600px;
    margin: 0 auto;
}

.navigation-grid {
    padding: 4rem 2rem;
    background-color: #f8f9fa;
}

.grid-container {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.nav-card {
    background-color: var(--white);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    cursor: pointer;
    border: 2px solid transparent;
}

.nav-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--secondary-blue);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    display: block;
}

.nav-card h3 {
    color: var(--primary-blue);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.nav-card p {
    color: var(--text-light);
    font-size: 1rem;
    line-height: 1.5;
}

.nav-card.disabled {
    opacity: 0.6;
    cursor: not-allowed;
    background-color: #f8f9fa;
}

.nav-card.disabled:hover {
    transform: none;
    box-shadow: var(--shadow);
    border-color: transparent;
}

.main-footer {
    background-color: var(--primary-blue);
    color: var(--white);
    padding: 2rem;
    text-align: center;
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
}

.footer-content p {
    font-size: 0.9rem;
    opacity: 0.8;
}