:root {
    --bg-color: #ffffff;
    --surface: #ffffff;
    --text-main: #000000;
    --text-muted: #666666;
    --primary: #000000;
    --primary-hover: #333333;
    --border: #e5e5e5;
    --danger: #ff3333;
    --success: #00cc66;
    --input-bg: #ffffff;
    --sidebar-bg: #fafafa;
}

[data-theme="dark"] {
    --bg-color: #0a0a0a;
    --surface: #141414;
    --text-main: #ffffff;
    --text-muted: #a0a0a0;
    --primary: #ffffff;
    --primary-hover: #cccccc;
    --border: #333333;
    --input-bg: #1a1a1a;
    --sidebar-bg: #111111;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    letter-spacing: -0.02em;
}

h1 { font-size: 2rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.5rem; margin-bottom: 1rem; }

/* Login */
.login-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background-color: var(--bg-color);
}

.login-box {
    background: var(--surface);
    padding: 48px;
    border: 1px solid var(--border);
    width: 100%;
    max-width: 440px;
}

.login-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-bottom: 32px;
}

.logo {
    width: 40px;
    height: 40px;
}

/* Forms */
.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 14px 16px;
    background: var(--input-bg);
    border: 1px solid var(--border);
    color: var(--text-main);
    font-family: inherit;
    font-size: 16px;
    transition: border-color 0.2s;
    border-radius: 0; /* Brutalist sharp edges */
}

.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 14px 24px;
    border: 1px solid var(--primary);
    cursor: pointer;
    font-weight: 600;
    font-size: 16px;
    text-align: center;
    transition: all 0.2s;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: 0;
}

.btn-primary {
    background: var(--primary);
    color: var(--bg-color);
    width: 100%;
}

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

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

.btn-secondary:hover {
    border-color: var(--primary);
}

.btn-sm {
    padding: 8px 16px;
    font-size: 12px;
    width: auto;
}

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

.sidebar {
    width: 280px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 32px 24px;
    display: flex;
    align-items: center;
    gap: 16px;
    border-bottom: 1px solid var(--border);
}

.brand-name {
    font-weight: 700;
    font-size: 20px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.sidebar-nav {
    flex: 1;
    padding: 24px 0;
}

.sidebar-nav a {
    display: block;
    padding: 16px 24px;
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: color 0.2s, background 0.2s;
}

.sidebar-nav a:hover, .sidebar-nav a.active {
    background: var(--surface);
    color: var(--text-main);
    border-right: 3px solid var(--primary);
}

.sidebar-footer {
    padding: 24px;
    border-top: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-muted);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.main-content {
    flex: 1;
    padding: 48px;
    overflow-y: auto;
    background: var(--bg-color);
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    padding-bottom: 24px;
    border-bottom: 2px solid var(--border);
}

.page-header .btn {
    width: auto;
}

/* Dashboard Stats */
.dashboard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
    margin-bottom: 48px;
}

.stat-card {
    background: var(--surface);
    padding: 32px;
    border: 1px solid var(--border);
}

.stat-card h3 {
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.stat-card p {
    font-size: 36px;
    font-weight: 700;
    line-height: 1;
}

/* Tables */
.table-container {
    background: var(--surface);
    border: 1px solid var(--border);
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th, .data-table td {
    padding: 16px 24px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.data-table th {
    font-weight: 600;
    color: var(--text-muted);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.data-table tr:last-child td {
    border-bottom: none;
}

/* Modals */
.modal {
    display: none;
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.8);
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-content {
    background: var(--surface);
    padding: 40px;
    width: 100%;
    max-width: 500px;
    position: relative;
    border: 1px solid var(--border);
}

.close {
    position: absolute;
    top: 24px; right: 24px;
    cursor: pointer;
    font-size: 24px;
    color: var(--text-muted);
    transition: color 0.2s;
}

.close:hover {
    color: var(--text-main);
}

.error-msg {
    color: var(--danger);
    font-size: 14px;
    margin-top: 12px;
    font-weight: 500;
}

/* Settings Grid */
.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.settings-card {
    background: var(--surface);
    padding: 32px;
    border: 1px solid var(--border);
}