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

:root {
    --primary: #ff0080;
    --secondary: #00ffff;
    --accent: #bf00ff;
    --bg-dark: #0a0a0f;
    --bg-darker: #05050a;
    --bg-card: #15151f;
    --bg-card-hover: #1a1a2a;
    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --text-muted: #666677;
    --border: #2a2a3a;
    --glow-primary: rgba(255, 0, 128, 0.5);
    --glow-secondary: rgba(0, 255, 255, 0.5);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang TC', 'Microsoft JhengHei', Roboto, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 900;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    letter-spacing: 2px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 2px;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 3px;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 100px 20px 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(255, 0, 128, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(0, 255, 255, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(191, 0, 255, 0.1) 0%, transparent 50%);
    animation: heroPulse 8s ease-in-out infinite;
}

@keyframes heroPulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.8; transform: scale(1.05); }
}

.hero-content {
    text-align: center;
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero-title {
    font-size: 5rem;
    font-weight: 900;
    background: linear-gradient(90deg, var(--primary), var(--secondary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 20px;
    letter-spacing: 8px;
    text-shadow: 0 0 60px var(--glow-primary);
    animation: titleGlow 3s ease-in-out infinite alternate;
}

@keyframes titleGlow {
    from { filter: drop-shadow(0 0 20px var(--glow-primary)); }
    to { filter: drop-shadow(0 0 40px var(--glow-secondary)); }
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-weight: 300;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(90deg, var(--primary), var(--accent));
    color: white;
    box-shadow: 0 4px 20px var(--glow-primary);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px var(--glow-primary);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 2px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--secondary);
    color: var(--secondary);
    box-shadow: 0 4px 20px var(--glow-secondary);
}

/* Section Styles */
section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 60px;
    color: var(--text-primary);
}

/* Features Section */
.features {
    background: var(--bg-darker);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--bg-card);
    padding: 40px 30px;
    border-radius: 20px;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary);
    box-shadow: 0 20px 40px rgba(255, 0, 128, 0.2);
}

.feature-icon {
    font-size: 3.5rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Preview Section */
.preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.preview-card {
    background: var(--bg-card);
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.preview-card:hover {
    transform: translateY(-5px);
    border-color: var(--secondary);
    box-shadow: 0 15px 40px rgba(0, 255, 255, 0.15);
}

.preview-placeholder {
    width: 100%;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
}

.preview-card h3 {
    padding: 20px 25px 10px;
    font-size: 1.2rem;
}

.preview-card p {
    padding: 0 25px 25px;
    color: var(--text-secondary);
}

/* Game Page */
.page-header {
    padding: 150px 0 80px;
    text-align: center;
    background: 
        radial-gradient(ellipse at 50% 0%, rgba(255, 0, 128, 0.1) 0%, transparent 60%);
}

.page-header h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-header p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.gameplay-section {
    padding: 60px 0;
}

.gameplay-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.gameplay-text h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.gameplay-text p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.8;
}

.gameplay-visual {
    background: var(--bg-card);
    border-radius: 20px;
    padding: 40px;
    border: 1px solid var(--border);
    text-align: center;
    min-height: 300px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.gameplay-visual .visual-icon {
    font-size: 5rem;
    margin-bottom: 20px;
}

.difficulty-section {
    background: var(--bg-darker);
    padding: 80px 0;
}

.difficulty-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 25px;
    margin-top: 40px;
}

.difficulty-card {
    background: var(--bg-card);
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    border: 2px solid var(--border);
    transition: all 0.3s;
}

.difficulty-card:hover {
    transform: scale(1.05);
}

.difficulty-card.easy { border-color: #00ff88; }
.difficulty-card.hard { border-color: #ff0080; }
.difficulty-card.insane { border-color: #bf00ff; }
.difficulty-card.another { border-color: #ff0000; }

.difficulty-level {
    font-size: 2.5rem;
    font-weight: 900;
    margin-bottom: 10px;
}

.difficulty-card.easy .difficulty-level { color: #00ff88; }
.difficulty-card.hard .difficulty-level { color: #ff0080; }
.difficulty-card.insane .difficulty-level { color: #bf00ff; }
.difficulty-card.another .difficulty-level { color: #ff0000; }

.difficulty-name {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.difficulty-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Songs Page */
.songs-section {
    padding: 60px 0;
}

.song-filters {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 8px 20px;
    border-radius: 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.3s;
    font-size: 0.9rem;
}

.filter-btn:hover,
.filter-btn.active {
    background: linear-gradient(90deg, var(--primary), var(--accent));
    color: white;
    border-color: transparent;
}

.song-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 25px;
}

.song-card {
    background: var(--bg-card);
    border-radius: 15px;
    overflow: hidden;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
    cursor: pointer;
}

.song-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary);
    box-shadow: 0 15px 40px rgba(255, 0, 128, 0.2);
}

.song-cover {
    width: 100%;
    height: 220px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
    position: relative;
}

.song-cover::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 50%;
    background: linear-gradient(transparent, rgba(0,0,0,0.5));
}

.song-difficulty {
    position: absolute;
    top: 15px;
    right: 15px;
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 700;
    z-index: 1;
}

.diff-ez { background: #00ff88; color: #000; }
.diff-hd { background: #ff0080; color: #fff; }
.diff-in { background: #bf00ff; color: #fff; }
.diff-at { background: #ff0000; color: #fff; }

.song-info {
    padding: 20px;
}

.song-title {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 8px;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.song-artist {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 10px;
}

.song-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* About Page */
.about-section {
    padding: 60px 0;
}

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

.about-text {
    background: var(--bg-card);
    padding: 40px;
    border-radius: 20px;
    border: 1px solid var(--border);
    margin-bottom: 40px;
}

.about-text h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.about-text p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 15px;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.contact-card {
    background: var(--bg-card);
    padding: 30px;
    border-radius: 15px;
    border: 1px solid var(--border);
    text-align: center;
    transition: all 0.3s;
}

.contact-card:hover {
    border-color: var(--secondary);
    transform: translateY(-5px);
}

.contact-icon {
    font-size: 2.5rem;
    margin-bottom: 15px;
}

.contact-card h3 {
    font-size: 1.1rem;
    margin-bottom: 10px;
}

.contact-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.disclaimer {
    background: rgba(255, 0, 128, 0.1);
    border: 1px solid rgba(255, 0, 128, 0.3);
    padding: 25px;
    border-radius: 15px;
    margin-top: 40px;
}

.disclaimer h3 {
    color: var(--primary);
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.disclaimer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
}

/* Footer */
.footer {
    background: var(--bg-darker);
    padding: 60px 0 30px;
    border-top: 1px solid var(--border);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.footer-section p {
    color: var(--text-muted);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section ul li a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section ul li a:hover {
    color: var(--primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-bottom p {
    margin-bottom: 8px;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-dark);
        flex-direction: column;
        padding: 20px;
        gap: 15px;
        border-bottom: 1px solid var(--border);
    }

    .nav-menu.active {
        display: flex;
    }

    .hamburger {
        display: flex;
    }

    .hero-title {
        font-size: 3rem;
        letter-spacing: 4px;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .gameplay-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .gameplay-visual {
        order: -1;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 250px;
        text-align: center;
    }

    .section-title {
        font-size: 1.8rem;
    }
}