:root {
    --bg-dark: #0b0f19;
    --bg-sidebar: #111827;
    --bg-card: #151c2c;
    --bg-card-hover: #1c263c;
    --bg-input: #0f172a;
    --border-color: #26334d;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --accent-primary: #38bdf8;
    --accent-green: #4ade80;
    --accent-amber: #fbbf24;
    --accent-red: #f87171;
    --accent-purple: #c084fc;
}

* {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
    height: 100vh;
    overflow: hidden;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
}

body {
    display: flex;
    flex-direction: column;
}

/* Top Header Bar */
header {
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 0 1.5rem;
    height: 56px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-shrink: 0;
    z-index: 10;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--text-main);
}

.brand h1 {
    margin: 0;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-primary);
    letter-spacing: -0.02em;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
    border-left: 1px solid var(--border-color);
    padding-left: 1.25rem;
}

.user-name {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* App Body Layout */
.app-body {
    display: flex;
    flex: 1;
    height: calc(100vh - 56px);
    overflow: hidden;
}

/* Full Height Left Vertical Sidebar */
.sidebar {
    width: 280px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    height: 100%;
    overflow: hidden;
}

.sidebar-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.25rem;
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: 0;
    margin: 0;
    width: 100%;
    border-left: 3px solid transparent;
    border-bottom: 1px solid rgba(38, 51, 77, 0.4);
    transition: all 0.15s ease;
}

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

.sidebar-item.active {
    background-color: #1e293b;
    color: var(--accent-primary);
    font-weight: 600;
    border-left: 3px solid var(--accent-primary);
}

.sidebar-header {
    font-size: 0.725rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    font-weight: 700;
    padding: 1rem 1.25rem 0.5rem 1.25rem;
    background-color: rgba(17, 24, 39, 0.8);
    border-bottom: 1px solid rgba(38, 51, 77, 0.4);
}

.sidebar-menu-list {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

.sidebar-menu-list::-webkit-scrollbar {
    width: 5px;
}

.sidebar-menu-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
}

.subnet-badge-count {
    background-color: var(--bg-input);
    color: var(--text-muted);
    font-size: 0.75rem;
    padding: 0.15rem 0.45rem;
    border-radius: 0.25rem;
}

/* Main Content Area */
.content-area {
    flex: 1;
    height: 100%;
    overflow-y: auto;
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
}

.card-title {
    margin: 0;
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text-main);
}

.grid-form {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.form-group label {
    font-size: 0.825rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-control {
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    padding: 0.6rem 0.8rem;
    color: var(--text-main);
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s;
}

.form-control:focus {
    border-color: var(--accent-primary);
}

/* Unified Button System */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.45rem 0.85rem;
    font-size: 0.85rem;
    font-weight: 500;
    font-family: inherit;
    line-height: 1.25;
    border-radius: 0.375rem;
    border: 1px solid transparent;
    background-color: transparent;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s ease-in-out;
    box-sizing: border-box;
    margin: 0;
    white-space: nowrap;
}

form.inline-form {
    display: inline-flex;
    margin: 0;
    padding: 0;
    vertical-align: middle;
}

.btn-sm {
    padding: 0.3rem 0.65rem;
    font-size: 0.8rem;
}

/* Color Outline Variants */
.btn-outline-primary {
    color: var(--accent-primary);
    border-color: rgba(56, 189, 248, 0.4);
    background-color: rgba(56, 189, 248, 0.05);
}
.btn-outline-primary:hover {
    background-color: rgba(56, 189, 248, 0.15);
    border-color: var(--accent-primary);
    color: #ffffff;
}

.btn-outline-success {
    color: var(--accent-green);
    border-color: rgba(74, 222, 128, 0.4);
    background-color: rgba(74, 222, 128, 0.05);
}
.btn-outline-success:hover {
    background-color: rgba(74, 222, 128, 0.15);
    border-color: var(--accent-green);
    color: #ffffff;
}

.btn-outline-danger {
    color: var(--accent-red);
    border-color: rgba(248, 113, 113, 0.4);
    background-color: rgba(248, 113, 113, 0.05);
}
.btn-outline-danger:hover {
    background-color: rgba(248, 113, 113, 0.18);
    border-color: var(--accent-red);
    color: #ffffff;
}

.btn-outline-secondary {
    color: var(--text-muted);
    border-color: var(--border-color);
    background-color: transparent;
}
.btn-outline-secondary:hover {
    color: var(--text-main);
    border-color: var(--text-muted);
    background-color: var(--bg-card-hover);
}

.btn-outline-purple {
    color: var(--accent-purple);
    border-color: rgba(192, 132, 252, 0.4);
    background-color: rgba(192, 132, 252, 0.05);
}
.btn-outline-purple:hover {
    background-color: rgba(192, 132, 252, 0.15);
    border-color: var(--accent-purple);
    color: #ffffff;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

th, td {
    padding: 0.85rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: var(--bg-input);
    color: var(--text-muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

tr:hover td {
    background-color: var(--bg-card-hover);
}

.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.2rem 0.5rem;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-online { background: rgba(74, 222, 128, 0.15); color: var(--accent-green); border: 1px solid rgba(74, 222, 128, 0.3); }
.badge-offline { background: rgba(248, 113, 113, 0.15); color: var(--accent-red); border: 1px solid rgba(248, 113, 113, 0.3); }
.badge-unknown { background: rgba(251, 191, 36, 0.15); color: var(--accent-amber); border: 1px solid rgba(251, 191, 36, 0.3); }
.badge-vlan { background: rgba(192, 132, 252, 0.15); color: var(--accent-purple); border: 1px solid rgba(192, 132, 252, 0.3); }
.badge-admin { background: rgba(56, 189, 248, 0.15); color: var(--accent-primary); border: 1px solid rgba(56, 189, 248, 0.3); }

.alert-success {
    background-color: rgba(74, 222, 128, 0.1);
    border: 1px solid var(--accent-green);
    color: var(--accent-green);
    padding: 0.85rem 1.25rem;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
}

.alert-error {
    background-color: rgba(248, 113, 113, 0.1);
    border: 1px solid var(--accent-red);
    color: var(--accent-red);
    padding: 0.85rem 1.25rem;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
}