:root {
    --primary-color: #2563eb;
    --secondary-color: #7c3aed;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --dark-color: #111827;
    --light-color: #f3f4f6;
    --border-radius: 0.5rem;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: #f9fafb;
}

/* Navigation */
.navbar {
    background: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

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

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
}

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

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

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

/* Grid System */
.grid {
    display: grid;
    gap: 2rem;
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

/* Cards */
.card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    overflow: hidden;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

.card-header {
    padding: 1.5rem;
    background: var(--light-color);
    border-bottom: 1px solid #e5e7eb;
}

.card-body {
    padding: 1.5rem;
}

.card-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--dark-color);
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Tables */
.table {
    width: 100%;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.table th,
.table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #e5e7eb;
}

.table th {
    background: var(--light-color);
    font-weight: 600;
    color: var(--dark-color);
}

.table tr:hover {
    background: #f9fafb;
}

/* Alerts */
.alert {
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.alert-success {
    background: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.9;
}

/* Auction Status Badge */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 500;
}

.badge-active {
    background: #d1fae5;
    color: #065f46;
}

.badge-pending {
    background: #fef3c7;
    color: #92400e;
}

.badge-completed {
    background: #e0e7ff;
    color: #3730a3;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 1rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .grid-3 {
        grid-template-columns: 1fr;
    }
}