:root {
    /* Color System - Slate/Zinc & Masonic Blue */
    --bg-surface: #f8fafc;       /* Slate 50 */
    --bg-card: #ffffff;
    --text-primary: #0f172a;     /* Slate 900 */
    --text-secondary: #64748b;   /* Slate 500 */
    
    --brand-blue: #0f172a;       /* Deep Navy */
    --brand-accent: #0369a1;     /* Sky 700 */
    --brand-gold: #b45309;       /* Amber 700 (Subtle gold) */
    
    --border-light: #e2e8f0;     /* Slate 200 */
    --input-bg: #ffffff;
    
    /* Metrics */
    --radius: 8px;
    --shadow-card: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --font-heading: 'Georgia', 'Times New Roman', serif; /* Classic Authority */
    --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

body {
    background-color: var(--bg-surface);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 15px; /* High legibility */
    line-height: 1.6;
    margin: 0;
    padding: 0;
    display: flex;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--brand-blue);
    margin-top: 0;
    font-weight: 700;
}

h1 { font-size: 1.875rem; }
h2 { font-size: 1.5rem; border-bottom: 2px solid var(--border-light); padding-bottom: 0.5rem; margin-bottom: 1.5rem; }

/* Sidebar */
.sidebar {
    width: 260px;
    background-color: var(--brand-blue);
    color: white;
    display: flex;
    flex-direction: column;
    padding: 24px 0;
    height: 100vh;
    position: fixed;
    box-shadow: 4px 0 24px rgba(0,0,0,0.05);
    z-index: 50;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 0 24px 24px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    margin-bottom: 16px;
    text-align: center;
}

.sidebar h3 {
    color: white;
    font-size: 1.25rem;
    letter-spacing: 1px;
    font-weight: 400;
    text-transform: uppercase;
}

.sidebar a {
    padding: 12px 24px;
    text-decoration: none;
    color: rgba(255,255,255,0.7);
    font-size: 0.95rem;
    display: block;
    transition: all 0.2s ease;
    border-left: 3px solid transparent;
}

.sidebar a:hover, .sidebar a.active {
    background-color: rgba(255,255,255,0.1);
    color: white;
    border-left-color: var(--brand-accent); /* Blue accent */
}

/* Main Content Area */
.content {
    margin-left: 260px;
    padding: 40px;
    flex: 1;
    width: 100%;
}

/* Cards */
.card, .container.card-style {
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    box-shadow: var(--shadow-card);
    padding: 32px;
    margin-bottom: 24px;
}

/* Forms */
input[type='text'], 
input[type='password'], 
input[type='email'], 
input[type='number'],
input[type='date'],
select, 
textarea {
    width: 100%;
    padding: 10px 12px;
    background-color: var(--input-bg);
    border: 1px solid var(--border-light);
    border-radius: 6px;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: border 0.15s ease, box-shadow 0.15s ease;
    box-sizing: border-box;
    margin-bottom: 1rem;
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--brand-accent);
    box-shadow: 0 0 0 3px rgba(3, 105, 161, 0.1);
}

label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
    font-size: 0.95rem;
}

.btn-primary {
    background-color: var(--brand-accent);
    color: white;
}
.btn-primary:hover {
    background-color: #0284c7;
    transform: translateY(-1px);
}

.btn-danger {
    background-color: #ef4444;
    color: white;
}
.btn-danger:hover {
    background-color: #dc2626;
}

/* Tables */
table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin: 1rem 0;
}

th {
    background-color: #f8fafc;
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-light);
    text-align: left;
}

td {
    padding: 16px;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

/* Mobile */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        width: 80%;
        max-width: 320px;
    }
    .sidebar.active {
        transform: translateX(0);
    }
    .content {
        margin-left: 0;
        padding: 20px;
    }
    
    .mobile-nav-toggle {
        display: block;
        position: fixed;
        bottom: 20px;
        right: 20px;
        background: var(--brand-accent);
        color: white;
        padding: 16px;
        border-radius: 50%;
        box-shadow: 0 4px 12px rgba(0,0,0,0.3);
        z-index: 100;
    }
}