/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #10b981;
    --primary-dark: #1d4ed8;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-700: #374151;
    --gray-900: #111827;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --radius: 0.5rem;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: var(--gray-900);
    background-color: var(--gray-50);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
    padding-left: 1rem;
}

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

.nav-link {
    color: var(--gray-700);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

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

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--gray-700);
    padding-right: 1rem;
}

/* Main Content */
.main {
    min-height: calc(100vh - 200px);
    padding: 2rem 0;
}

/* Cards */
.card {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

.card-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 1.5rem;
    color: var(--gray-900);
}

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--gray-700);
}

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-input.error {
    border-color: var(--danger-color);
}

.error-message {
    color: var(--danger-color);
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: none;
}

.error-message.show {
    display: block;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

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

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

.btn-secondary {
    background-color: var(--gray-200);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background-color: var(--gray-300);
}

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

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

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

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: var(--radius);
    margin-bottom: 1.5rem;
    display: none;
}

.alert.show {
    display: block;
}

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

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

.alert-info {
    background-color: #dbeafe;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

/* Countdown Timer */
.countdown {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin: 2rem 0;
}

.countdown-item {
    text-align: center;
    min-width: 60px;
}

.countdown-value {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
    display: block;
}

.countdown-label {
    font-size: 0.875rem;
    color: var(--gray-700);
    text-transform: uppercase;
}

/* Leaderboard */
.leaderboard {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.leaderboard th {
    background-color: var(--gray-100);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--gray-700);
}

.leaderboard td {
    padding: 1rem;
    border-bottom: 1px solid var(--gray-200);
}

.leaderboard tr:hover {
    background-color: var(--gray-50);
}

.rank-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    font-weight: bold;
    color: white;
}

.rank-1 { background-color: #fbbf24; }
.rank-2 { background-color: #94a3b8; }
.rank-3 { background-color: #d97706; }

/* Admin Panel */
.admin-section {
    margin-bottom: 3rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
    display: block;
}

.stat-label {
    color: var(--gray-700);
    font-size: 0.875rem;
    text-transform: uppercase;
}

/* Pending Referrals */
.pending-list {
    list-style: none;
}

.pending-item {
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.pending-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* Footer */
.footer {
    background: var(--gray-900);
    color: white;
    padding: 3rem 0;
    margin-top: 4rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-section {
    flex: 1;
    min-width: 250px;
}

.footer-title {
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 1rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: var(--gray-200);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: white;
}

.copyright {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2rem;
    border-top: 1px solid var(--gray-700);
    color: var(--gray-400);
}

/* Responsive */
@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: var(--shadow);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .countdown {
        flex-wrap: wrap;
    }
    
    .countdown-item {
        min-width: 45px;
    }
    
    .countdown-value {
        font-size: 1.5rem;
    }
    
    .leaderboard {
        display: block;
        overflow-x: auto;
    }
    
    .footer-content {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .card {
        padding: 1rem;
    }
    
    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    
    .pending-actions {
        flex-direction: column;
    }
}