:root {
    /* Color Palette - Healthy & Premium */
    --primary: hsl(142, 69%, 58%); /* Emerald Green */
    --primary-glow: hsla(142, 69%, 58%, 0.3);
    --secondary: hsl(210, 100%, 50%); /* High-tech blue */
    --bg-dark: hsl(222, 47%, 11%);
    --bg-card: hsla(222, 47%, 15%, 0.8);
    --text-main: hsl(210, 40%, 98%);
    --text-muted: hsl(215, 20%, 65%);
    --sidebar-width: 260px;
    --acc-red: hsl(0, 84%, 60%);
    --acc-yellow: hsl(48, 96%, 53%);
    --acc-blue: hsl(199, 89%, 48%);
    
    /* Layout Tokens */
    --radius-lg: 16px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --shadow-glow: 0 0 20px var(--primary-glow);
}

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

body.dark-theme {
    background-color: var(--bg-dark);
    color: var(--text-main);
    overflow: hidden;
}

#app {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* Glassmorphism Sidebar */
.glass {
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-right: 1px solid hsla(210, 40%, 98%, 0.1);
}

#sidebar {
    width: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    padding: 2rem 1rem;
    z-index: 10;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 2.5rem;
    padding-left: 0.5rem;
}

nav {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.85rem 1rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1rem;
}

.nav-btn:hover {
    background: hsla(210, 40%, 98%, 0.05);
    color: var(--text-main);
}

.nav-btn.active {
    background: var(--primary);
    color: white;
    box-shadow: var(--shadow-glow);
}

.sidebar-footer {
    padding: 1rem;
    border-top: 1px solid hsla(210, 40%, 98%, 0.1);
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.9rem;
}

/* Main Content Area */
#main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    padding: 2rem 3rem;
}

.main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

#current-time {
    color: var(--text-muted);
    font-family: monospace;
    font-size: 1.1rem;
}

.icon-btn {
    cursor: pointer;
    color: var(--text-muted);
    transition: color 0.2s;
}

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

/* Card System */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    border: 1px solid hsla(210, 40%, 98%, 0.05);
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
}

/* POS UI specific */
.product-card {
    overflow: hidden;
    padding: 0;
}

.product-img {
    width: 100%;
    height: 180px;
    background: #333;
    object-fit: cover;
}

.product-info {
    padding: 1rem;
}

.price-tag {
    color: var(--primary);
    font-weight: 700;
    font-size: 1.25rem;
}

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

.animate-in {
    animation: fadeIn 0.4s forwards ease-out;
}

/* Responsive */
@media (max-width: 1024px) {
    #sidebar {
        width: 80px;
        padding: 2rem 0.5rem;
    }
    .logo span, .nav-btn span, .sidebar-footer span {
        display: none;
    }
    #main-content {
        padding: 2rem 1rem;
    }
}
/* Modal Systems */
.modal-overlay, .modal {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-content {
    background: var(--bg-card);
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid hsla(210, 40%, 98%, 0.1);
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    max-width: 450px;
    width: 90%;
    position: relative;
}