:root {
    --bg-primary: #0f0f23;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #16213e;
    --accent-primary: #667eea;
    --accent-secondary: #764ba2;
    --text-primary: #ffffff;
    --text-secondary: #b8b8d4;
    --text-muted: #6b7280;
    --border-color: #2d3748;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --shadow: rgba(0, 0, 0, 0.3);
}

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

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

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 280px;
    height: 100vh;
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    padding: 30px 0;
    box-shadow: 4px 0 20px var(--shadow);
    z-index: 1000;
    overflow-y: auto;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 0 25px 30px;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 25px;
}

.sidebar-header h2 {
    font-size: 26px;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-header p {
    font-size: 13px;
    color: var(--text-secondary);
    opacity: 0.8;
}

.sidebar-menu {
    list-style: none;
    padding: 0 15px;
}

.sidebar-menu li {
    margin: 8px 0;
}

.sidebar-menu a {
    display: flex;
    align-items: center;
    padding: 14px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 12px;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
    font-weight: 500;
}

.sidebar-menu a:hover {
    background: rgba(102, 126, 234, 0.1);
    color: var(--text-primary);
    transform: translateX(5px);
}

.sidebar-menu a.active {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.2), rgba(118, 75, 162, 0.2));
    color: var(--accent-primary);
    border-left-color: var(--accent-primary);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.2);
}

/* Main Content */
.main-content {
    margin-left: 280px;
    padding: 30px;
    min-height: 100vh;
}

.header {
    background: var(--bg-secondary);
    padding: 25px 35px;
    border-radius: 16px;
    margin-bottom: 30px;
    box-shadow: 0 4px 20px var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid var(--border-color);
}

.header h1 {
    font-size: 32px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 20px;
}

.user-info span {
    color: var(--text-secondary);
    font-size: 14px;
}

.logout-btn {
    padding: 10px 20px;
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
}

.logout-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(239, 68, 68, 0.4);
}

/* Cards */
.content-card {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 35px;
    box-shadow: 0 4px 20px var(--shadow);
    border: 1px solid var(--border-color);
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Stats Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-tertiary));
    padding: 30px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px var(--shadow);
}

.stat-card h3 {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-card p {
    font-size: 42px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
}

.btn-success {
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, var(--error), #dc2626);
    color: white;
}

.btn-warning {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
}

.btn-secondary {
    background: linear-gradient(135deg, #6b7280, #4b5563);
    color: white;
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 14px;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 14px;
    transition: all 0.3s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Tables */
.table-container {
    overflow-x: auto;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-secondary);
}

thead {
    background: var(--bg-tertiary);
}

th {
    padding: 16px;
    text-align: left;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 1px;
    border-bottom: 2px solid var(--border-color);
}

td {
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

tr:hover {
    background: rgba(102, 126, 234, 0.05);
}

/* Modal */
.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(5px);
    animation: fadeIn 0.3s ease;
}

.modal-overlay.show {
    display: flex;
}

.modal-content {
    background: var(--bg-secondary);
    padding: 35px;
    border-radius: 20px;
    max-width: 600px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 24px;
    font-weight: 700;
}

/* Alerts */
.alert {
    padding: 16px 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    border-left: 4px solid;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.alert-success {
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--success);
    color: var(--success);
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--error);
    color: var(--error);
}

/* Loading */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-primary);
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .main-content {
        margin-left: 0;
        padding: 20px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
}