:root {
    --bg-main: #f8fafc;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent: #1e293b;
    --accent-hover: #0f172a;
    --success: #166534;
    --success-bg: #f0fdf4;
    --error: #991b1b;
    --error-bg: #fef2f2;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    padding: 24px 16px;
    line-height: 1.5;
}

.app-layout {
    max-width: 960px;
    margin: 0 auto;
}

/* Header & Navigation */
header {
    margin-bottom: 24px;
}

.brand {
    font-size: 1.1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: 16px;
    text-transform: uppercase;
}

nav {
    display: flex;
    gap: 8px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
}

nav a {
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    padding: 6px 12px;
    border-radius: 6px;
    transition: all 0.15s ease;
}

nav a:hover {
    color: var(--text-primary);
    background-color: #f1f5f9;
}

nav a.active {
    color: var(--text-primary);
    background-color: #e2e8f0;
    font-weight: 600;
}

/* Container & Cards */
.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
}

h1 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 16px;
    letter-spacing: -0.01em;
}

h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
}

/* Form Elements */
label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

input[type="text"],
input[type="email"],
select {
    width: 100%;
    padding: 9px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    color: var(--text-primary);
    background-color: #ffffff;
    outline: none;
    transition: border-color 0.15s ease;
}

input[type="text"]:focus,
input[type="email"]:focus,
select:focus {
    border-color: #94a3b8;
}

.btn-primary {
    background-color: var(--accent);
    color: #ffffff;
    border: none;
    padding: 10px 16px;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.15s ease;
    width: 100%;
}

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

.btn-secondary {
    background-color: #ffffff;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
}

.btn-secondary:hover {
    background-color: #f1f5f9;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

th {
    text-align: left;
    padding: 10px 12px;
    background-color: #f8fafc;
    color: var(--text-secondary);
    font-weight: 600;
    border-bottom: 1px solid var(--border-color);
}

td {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
}

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