:root {
    --primary-color: #3b82f6; /* Modern Blue */
    --secondary-color: #64748b;
    --accent-color: #f59e0b; /* Amber for highlights */
    --bg-dark: #0f172a; /* Slate 900 */
    --bg-darker: #020617; /* Slate 950 */
    --bg-card: #1e293b; /* Slate 800 */
    --text-main: #f1f5f9; /* Slate 100 */
    --text-muted: #94a3b8; /* Slate 400 */
    --border-color: #334155; /* Slate 700 */
    --sidebar-width: 260px;
    --header-height: 64px;
}

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

body {
    font-family: 'Pretendard', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* Layout */
.layout-container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-darker);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100%;
    transition: transform 0.3s ease;
    z-index: 100;
}

.logo-area {
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 1.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--primary-color);
    letter-spacing: -0.5px;
    border-bottom: 1px solid var(--border-color);
}

.nav-menu {
    flex: 1;
    padding: 1.5rem 1rem;
}

.nav-item {
    margin-bottom: 0.5rem;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    color: var(--text-muted);
    font-weight: 500;
    transition: all 0.2s;
}

.nav-link:hover, .nav-link.active {
    background-color: var(--primary-color);
    color: white;
}

.nav-link i {
    margin-right: 0.75rem;
    width: 20px;
    text-align: center;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
}

.top-header {
    height: var(--header-height);
    background-color: var(--bg-dark);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2rem;
    position: sticky;
    top: 0;
    z-index: 90;
}

.page-content {
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

/* Components */
.card {
    background-color: var(--bg-card);
    border-radius: 1rem;
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: filter 0.2s;
    border: none;
    font-size: 0.95rem;
}

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

.btn-primary:hover {
    filter: brightness(1.1);
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
}

.btn-outline:hover {
    border-color: var(--text-main);
    color: var(--text-main);
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.form-control, .form-select {
    width: 100%;
    padding: 0.75rem;
    border-radius: 0.5rem;
    background-color: var(--bg-darker);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-size: 1rem;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.3);
}

/* Responsive Grid */
.grid {
    display: grid;
    gap: 1.5rem;
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

/* Utilities */
.text-xl { font-size: 1.25rem; font-weight: 700; margin-bottom: 1rem; }
.text-lg { font-size: 1.125rem; font-weight: 600; margin-bottom: 0.5rem; }
.text-muted { color: var(--text-muted); }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.gap-2 { gap: 0.5rem; }

/* Status Badges */
.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-active { background-color: rgba(59, 130, 246, 0.2); color: #60a5fa; }
.badge-draft { background-color: rgba(148, 163, 184, 0.2); color: #cbd5e1; }

/* Mobile Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    .sidebar.open {
        transform: translateX(0);
    }
    .main-content {
        margin-left: 0;
    }
    .grid-cols-2, .grid-cols-3, .grid-cols-4 {
        grid-template-columns: 1fr;
    }
}