:root {
    --primary-color: #4f46e5; /* Indigo 600 */
    --primary-hover: #4338ca; /* Indigo 700 */
    --secondary-color: #10b981; /* Emerald 500 */
    --bg-color: #f3f4f6; /* Gray 100 */
    --card-bg: #ffffff;
    --text-main: #111827; /* Gray 900 */
    --text-muted: #6b7280; /* Gray 500 */
    --border-color: #e5e7eb; /* Gray 200 */
    --sidebar-width: 260px;
    --header-height: 64px;
    --transition-speed: 0.3s;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.5s ease-out forwards;
}

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

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--card-bg);
    border-right: 1px solid var(--border-color);
    position: fixed;
    height: 100vh;
    padding: 1.5rem;
    transition: var(--transition-speed);
    z-index: 10;
}

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 2rem;
    padding-top: calc(var(--header-height) + 2rem);
}

/* Header */
.top-header {
    height: var(--header-height);
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: fixed;
    top: 0;
    right: 0;
    left: var(--sidebar-width);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2rem;
    z-index: 5;
}

/* Components */
.card {
    background-color: var(--card-bg);
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-speed);
    margin-bottom: 1.5rem;
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-speed);
    border: none;
    outline: none;
    text-decoration: none;
}

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

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

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

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

/* Form Elements */
.form-group {
    margin-bottom: 1rem;
}

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-main);
    margin-bottom: 0.5rem;
}

.form-control {
    width: 100%;
    padding: 0.625rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 0.875rem;
    transition: var(--transition-speed);
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.1);
}

/* Utilities */
.text-center { text-align: center; }
.justify-between { justify-content: space-between; }
.flex { display: flex; }
.items-center { align-items: center; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.text-xl { font-size: 1.25rem; font-weight: 600; }
.text-2xl { font-size: 1.5rem; font-weight: 700; }
.text-sm { font-size: 0.875rem; }
.text-muted { color: var(--text-muted); }

/* Sidebar Navigation */
.nav-link {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    color: var(--text-muted);
    text-decoration: none;
    border-radius: 0.5rem;
    margin-bottom: 0.5rem;
    transition: var(--transition-speed);
}

.nav-link:hover, .nav-link.active {
    background-color: #eef2ff;
    color: var(--primary-color);
}

.nav-link i {
    margin-right: 0.75rem;
}

/* Login Page Specifics */
.login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    background: linear-gradient(135deg, #4f46e5 0%, #10b981 100%);
}

.login-card {
    width: 100%;
    max-width: 400px;
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}