:root {
    --sidebar-width: 260px;
    --navbar-height: 60px;
    --color-primary: #0891b2;
    --color-primary-dark: #0e7490;
    --color-bg: #f8fafc;
    --color-sidebar: #ffffff;
    --color-text: #334155;
    --color-text-muted: #64748b;
}

* { box-sizing: border-box; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
}

/* Navbar */
.navbar {
    height: var(--navbar-height);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}
.navbar-brand {
    font-weight: 600;
    font-size: 1.25rem;
}
.navbar-brand i { margin-right: 0.5rem; }

/* Sidebar */
.sidebar {
    position: fixed;
    top: var(--navbar-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--color-sidebar);
    border-right: 1px solid #e2e8f0;
    overflow-y: auto;
    padding: 1.5rem 0;
}

.sidebar-section {
    padding: 0 1rem;
    margin-bottom: 1.5rem;
}

.sidebar-title {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    padding: 0 0.75rem;
    margin-bottom: 0.5rem;
}

.sidebar .nav-link {
    color: var(--color-text);
    padding: 0.6rem 0.75rem;
    border-radius: 0.5rem;
    margin: 0.125rem 0;
    font-size: 0.9rem;
    transition: all 0.15s ease;
}
.sidebar .nav-link i {
    width: 1.25rem;
    margin-right: 0.5rem;
    opacity: 0.7;
}
.sidebar .nav-link:hover {
    background: #f1f5f9;
    color: var(--color-primary);
}
.sidebar .nav-link.active {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
}
.sidebar .nav-link.active i { opacity: 1; }

/* Main content */
.main-wrapper {
    margin-left: var(--sidebar-width);
    padding-top: var(--navbar-height);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.main-content {
    flex: 1;
    padding: 2rem;
}

/* Footer */
footer {
    background: var(--color-sidebar);
    border-top: 1px solid #e2e8f0;
    padding: 1rem 2rem;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* Code blocks */
pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 1rem 1.25rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    overflow-x: auto;
}
pre code { background: none; color: inherit; padding: 0; }

code {
    background: #e2e8f0;
    color: #0f172a;
    padding: 0.125rem 0.375rem;
    border-radius: 0.25rem;
    font-size: 0.875em;
}

/* Alerts */
.alert { border: none; border-radius: 0.5rem; }
.alert-info { background: #e0f2fe; color: #0369a1; }
.alert-success { background: #dcfce7; color: #15803d; }
.alert-warning { background: #fef3c7; color: #b45309; }
.alert-danger { background: #fee2e2; color: #b91c1c; }

/* Cards */
.card {
    border: 1px solid #e2e8f0;
    border-radius: 0.5rem;
    box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}
.card-header {
    background: var(--color-bg);
    border-bottom: 1px solid #e2e8f0;
    font-weight: 600;
}

/* Links */
a { color: var(--color-primary); }
a:hover { color: var(--color-primary-dark); }

.error-block { text-align: center; max-width: 480px; }
.error-code {
    font-size: 7rem;
    font-weight: 700;
    line-height: 1;
    color: var(--color-primary);
    opacity: 0.15;
}
.error-title { font-size: 1.75rem; font-weight: 600; margin-top: -1.5rem; }
.error-sub { color: var(--color-text-muted); margin-top: 0.5rem; }

/* Responsive */
@media (max-width: 991px) {
    .sidebar {
        position: static;
        width: 100%;
        border-right: none;
        border-bottom: 1px solid #e2e8f0;
        padding: 1rem 0;
    }
    .main-wrapper {
        margin-left: 0;
    }
    .sidebar-section { margin-bottom: 0.5rem; }
}