:root {
    --primary-color: #2563eb;
    --primary-color-hover: #1d4ed8;
    --bg-color: #f3f4f6;
    --surface-color: #ffffff;
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --border-color: #e5e7eb;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
}

/* Utils */
.hidden {
    display: none !important;
}

/* Login */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.login-card {
    background: var(--surface-color);
    padding: 2.5rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    width: 100%;
    max-width: 400px;
}

.login-card h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.input-group {
    margin-bottom: 1.5rem;
}

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

.input-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

.input-group input:focus {
    border-color: var(--primary-color);
}

.btn-primary {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    display: block;
    text-align: center;
}

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

.alert {
    margin-top: 1rem;
    padding: 0.75rem;
    border-radius: 4px;
    font-size: 0.875rem;
    text-align: center;
}

.alert-error {
    background-color: #fee2e2;
    color: #991b1b;
}

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

.sidebar {
    width: 250px;
    background-color: var(--surface-color);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    height: 80px;
}

.sidebar-logo {
    max-width: 150px;
    max-height: 50px;
    object-fit: contain;
}

.sidebar-nav {
    padding: 1rem 0;
    flex-grow: 1;
}

.nav-item {
    display: block;
    padding: 0.75rem 1.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    transition: background-color 0.2s, color 0.2s;
    font-weight: 500;
}

.nav-item:hover, .nav-item.active {
    background-color: var(--bg-color);
    color: var(--primary-color);
    border-left: 4px solid var(--primary-color);
}

.main-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.topbar {
    height: 60px;
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: 0 2rem;
}

.content-area {
    padding: 2rem;
    flex-grow: 1;
    overflow-y: auto;
}