:root {
    /* Color Palette - Premium & Modern (Refined) */
    --primary-color: #4F46E5; /* Indigo 600 */
    --primary-hover: #4338CA; /* Indigo 700 */
    --primary-soft: #EEF2FF; /* Indigo 50 */
    
    --secondary-color: #10B981; /* Emerald 500 */
    --accent-color: #F59E0B; /* Amber 500 */
    --danger-color: #EF4444; /* Red 500 */
    
    --bg-body: #F8FAFC; /* Slate 50 */
    --bg-surface: #FFFFFF;
    --bg-surface-hover: #F8FAFC; /* Slate 50 */
    
    --text-main: #1E293B; /* Slate 800 */
    --text-secondary: #64748B; /* Slate 500 */
    --text-muted: #94A3B8; /* Slate 400 */
    --text-light: #FFFFFF;
    
    --border-color: #E2E8F0; /* Slate 200 */
    --border-focus: #6366F1; /* Indigo 500 */
    
    /* Spacing - Compact */
    --spacing-xs: 0.125rem;
    --spacing-sm: 0.375rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1.25rem;
    --spacing-xl: 2rem;
    
    /* Typography - Compact */
    --font-main: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, "Helvetica Neue", "Segoe UI", "Apple SD Gothic Neo", "Malgun Gothic", "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", sans-serif;
    --font-heading: 'Pretendard', sans-serif;
    
    --text-xs: 0.75rem;
    --text-sm: 0.8125rem;  /* 13px */
    --text-base: 0.9375rem; /* 15px */
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    
    /* Shadows - Subtle */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-base: all 0.15s ease-in-out;
}

/* Reset & Base Styles */
body {
    font-family: var(--font-main);
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.5;
    font-size: var(--text-base);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    letter-spacing: -0.015em;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-base);
}

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

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
}

/* Layout Utilities */
.container-custom {
    max-width: 1200px; /* Restore wider width for better spacing */
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Card Component - Compact */
.card-custom {
    background-color: var(--bg-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition-base);
}

.card-custom:hover {
    box-shadow: var(--shadow-md);
    border-color: #CBD5E1; /* Slate 300 */
}

.card-header-custom {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-surface);
}

.card-body-custom {
    padding: var(--spacing-lg);
}

/* Button Component - Compact */
.btn-custom {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.4rem 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: var(--transition-base);
    cursor: pointer;
    border: 1px solid transparent;
    font-size: var(--text-sm);
    line-height: 1.25rem;
}

.btn-primary-custom {
    background-color: var(--primary-color);
    color: var(--text-light);
}

.btn-primary-custom:hover {
    background-color: var(--primary-hover);
    color: var(--text-light);
    box-shadow: 0 2px 4px rgba(79, 70, 229, 0.2);
}

.btn-outline-custom {
    background-color: transparent;
    border-color: var(--border-color);
    color: var(--text-secondary);
}

.btn-outline-custom:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background-color: var(--primary-soft);
}

/* Navbar Customization - Compact */
.navbar-custom {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    min-height: 3.5rem;
    display: flex;
    align-items: center; /* Ensure vertical centering */
}

.navbar-brand-custom {
    font-weight: 800;
    font-size: 1.25rem;
    color: #000 !important;
    letter-spacing: -0.03em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.navbar-brand-custom:hover {
    color: #000 !important;
}

.nav-link-custom {
    color: var(--text-secondary) !important;
    font-weight: 600;
    padding: 0.375rem 0.75rem !important;
    border-radius: var(--radius-md);
    transition: var(--transition-base);
    font-size: var(--text-sm);
}

.nav-link-custom:hover, .nav-link-custom.active {
    color: var(--primary-color) !important;
    background-color: var(--primary-soft);
}

/* Sidebar Customization - Compact */
.sidebar-custom {
    background-color: var(--bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    padding: var(--spacing-md);
    position: sticky;
    top: 4.5rem; /* Adjusted for compact navbar */
}

.sidebar-heading {
    font-size: 0.6875rem; /* 11px */
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    padding-left: 0.5rem;
    font-weight: 700;
}

.sidebar-link {
    display: flex;
    align-items: center;
    padding: 0.5rem 0.75rem;
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    margin-bottom: 1px;
    transition: var(--transition-base);
    font-weight: 500;
    font-size: var(--text-sm);
}

.sidebar-link:hover {
    background-color: var(--bg-surface-hover);
    color: var(--text-main);
}

.sidebar-link.active {
    background-color: var(--primary-soft);
    color: var(--primary-color);
    font-weight: 600;
}

.sidebar-link i {
    margin-right: 0.5rem;
    width: 16px;
    text-align: center;
    opacity: 0.7;
    font-size: 0.875rem;
}

.sidebar-link.active i {
    opacity: 1;
}

/* Badge - Compact */
.badge-custom {
    padding: 0.15rem 0.4rem;
    border-radius: var(--radius-sm);
    font-size: 0.6875rem;
    font-weight: 600;
    line-height: 1;
}

.badge-custom.bg-light {
    background-color: #F1F5F9 !important; /* Slate 100 */
    color: var(--text-muted) !important;
}

.badge-primary {
    background-color: var(--primary-soft);
    color: var(--primary-color);
}

/* Form Controls - Compact */
.form-control-custom {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.5rem 0.75rem;
    transition: var(--transition-base);
    background-color: var(--bg-surface);
    font-size: var(--text-sm);
}

.form-control-custom:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.1);
    outline: none;
}

.form-select-sm {
    padding-top: 0.35rem;
    padding-bottom: 0.35rem;
    padding-left: 0.6rem;
    font-size: var(--text-sm);
}

/* Footer */
.footer-custom {
    background-color: var(--bg-surface);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0 1.5rem;
    margin-top: auto;
}

/* Utilities */
.text-gradient {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hover-bg-light:hover {
    background-color: var(--bg-surface-hover) !important;
}

/* Mobile Optimizations */
@media (max-width: 768px) {
    .container-custom {
        padding: 0 var(--spacing-sm);
    }
    
    .card-custom {
        border-radius: 0;
        border-left: none;
        border-right: none;
        box-shadow: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .navbar-brand-custom {
        font-size: 1.125rem;
    }

    .navbar-collapse {
        background-color: var(--bg-surface);
        padding: var(--spacing-md);
        border-radius: var(--radius-md);
        margin-top: var(--spacing-sm);
        box-shadow: var(--shadow-lg);
        border: 1px solid var(--border-color);
    }
}