:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --header-bg: #ffffff;
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --card-bg: #1e293b;
    --border-color: #334155;
    --header-bg: #1e293b;
    --secondary-color: #94a3b8;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.5;
    transition: background-color 0.3s, color 0.3s;
}

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

header {
    background: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo a {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-color);
    text-decoration: none;
    letter-spacing: -0.025em;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--secondary-color);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--primary-color);
}

main {
    padding: 3rem 0;
    min-height: 80vh;
}

.hero {
    text-align: center;
    padding: 4rem 1rem;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(37, 99, 235, 0.05) 100%);
    border-radius: 24px;
    margin-bottom: 3rem;
}

[data-theme="dark"] .hero {
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.2) 0%, rgba(15, 23, 42, 0.5) 100%);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none !important;
    transition: all 0.2s;
    cursor: pointer;
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white !important;
}

.btn-secondary {
    background-color: var(--card-bg);
    color: var(--text-color) !important;
    border-color: var(--border-color);
}

.event-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.event-card {
    background: var(--card-bg);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
}

.event-card-content {
    padding: 1.5rem;
}

.theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 8px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    transition: all 0.2s;
}

.theme-toggle:hover {
    border-color: var(--primary-color);
}

.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}

.alert-success { background: rgba(34, 197, 94, 0.1); color: #22c55e; border: 1px solid rgba(34, 197, 94, 0.2); }
.alert-danger { background: rgba(239, 68, 68, 0.1); color: #ef4444; border: 1px solid rgba(239, 68, 68, 0.2); }

form .form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-bg);
    color: var(--text-color);
}

footer {
    background: var(--header-bg);
    padding: 4rem 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-links a {
    color: var(--secondary-color);
    text-decoration: none;
}