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

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --success: #059669;
    --warning: #d97706;
    --danger: #dc2626;
    --dark-bg: #0f172a;
    --light-bg: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
}

body.dark {
    --light-bg: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --border: #334155;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, 'Roboto', sans-serif;
    background: var(--light-bg);
    color: var(--text-main);
    font-size: 16px;
    line-height: 1.6;
    transition: background 0.3s, color 0.2s;
}

/* header */
.header {
    position: sticky;
    top: 0;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(16px);
    z-index: 1000;
    border-bottom: 1px solid var(--border);
    padding: 1rem 2rem;
}
body.dark .header { background: rgba(15,23,42,0.95); }
.nav-container {
    max-width: 1300px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), #7c3aed);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    cursor: pointer;
}
.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}
.nav-menu a {
    text-decoration: none;
    color: var(--text-main);
    font-weight: 500;
    transition: 0.2s;
}
.nav-menu a:hover { color: var(--primary); }
.dark-toggle {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 50%;
    width: 42px;
    height: 42px;
    cursor: pointer;
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: 0.2s;
}
.dark-toggle:hover {
    transform: scale(1.05);
}
.hamburger {
    display: none;
    font-size: 1.8rem;
    cursor: pointer;
}

/* main container */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 2rem;
}

/* About Page Styles */
.about-page {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 2.5rem;
    box-shadow: 0 20px 35px -12px rgba(0,0,0,0.1);
}

.about-header {
    text-align: center;
    margin-bottom: 2.5rem;
}
.about-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary), #8b5cf6);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}
.about-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.8rem;
    margin: 2.5rem 0;
}
.feature-card {
    background: var(--light-bg);
    border-radius: 1.2rem;
    padding: 1.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}
.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}
.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
    color: var(--primary);
}
.feature-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.category-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin: 1.5rem 0;
    justify-content: center;
}
.category-badge {
    background: var(--primary);
    color: white;
    padding: 0.4rem 1.2rem;
    border-radius: 30px;
    font-size: 0.9rem;
    font-weight: 500;
}

.ads-section {
    background: linear-gradient(135deg, var(--primary), #7c3aed);
    color: white;
    border-radius: 1.2rem;
    padding: 2rem;
    text-align: center;
    margin: 2rem 0 1rem;
}
.ads-section h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
}
.ads-section p {
    margin-bottom: 1.5rem;
    opacity: 0.95;
}
.contact-btn {
    display: inline-block;
    background: white;
    color: var(--primary);
    padding: 0.8rem 2rem;
    border-radius: 40px;
    text-decoration: none;
    font-weight: bold;
    transition: transform 0.2s;
}
.contact-btn:hover {
    transform: scale(1.05);
}

.divider {
    height: 1px;
    background: var(--border);
    margin: 2rem 0;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
        margin: 1rem auto;
    }
    .about-page {
        padding: 1.5rem;
    }
    .about-header h1 {
        font-size: 1.8rem;
    }
    .nav-menu {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--card-bg);
        padding: 1rem;
        gap: 1rem;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-md);
    }
    .nav-menu.active {
        display: flex;
    }
    .hamburger {
        display: block;
    }
    .header {
        padding: 0.8rem 1rem;
    }
}