/* Modern Design - v1.2 */

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

:root {
    /* Modern color palette */
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --primary-light: #dbeafe;
    --success-color: #10b981;
    --success-light: #d1fae5;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    
    /* Neutral colors */
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #0f172a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    
    /* Typography scale */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    touch-action: manipulation;
}

#app {
    max-width: 900px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: white;
    box-shadow: var(--shadow-lg);
}

/* ========== HEADER ========== */
header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    color: white;
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

header h1 {
    font-size: var(--text-2xl);
    font-weight: 700;
    letter-spacing: -0.025em;
}

.sync-status {
    position: absolute;
    top: 1rem;
    right: 1rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: var(--text-xs);
    background: rgba(255,255,255,0.15);
    padding: 0.5rem 0.875rem;
    border-radius: 999px;
    backdrop-filter: blur(10px);
}

.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #94a3b8;
    animation: pulse 2s ease-in-out infinite;
}

.status-dot.online {
    background: #10b981;
    box-shadow: 0 0 12px rgba(16, 185, 129, 0.6);
}

.status-dot.offline {
    background: var(--warning-color);
    animation: none;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

/* ========== SCREENS ========== */
.screen {
    display: none;
    flex: 1;
    padding: 2rem;
    animation: fadeInUp 0.4s ease-out;
}

.screen.active {
    display: block;
}

@keyframes fadeInUp {
    from { 
        opacity: 0; 
        transform: translateY(20px); 
    }
    to { 
        opacity: 1; 
        transform: translateY(0); 
    }
}

.screen-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.screen-header h2 {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--text-color);
}

/* ========== TYPOGRAPHY ========== */
h2 {
    font-size: var(--text-2xl);
    margin-bottom: 2rem;
    text-align: center;
    color: var(--text-color);
    font-weight: 600;
    letter-spacing: -0.025em;
}

h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

/* ========== BUTTONS ========== */
.btn-back {
    background: transparent;
    border: 2px solid var(--border-color);
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-muted);
}

.btn-back:hover {
    background: var(--bg-color);
    border-color: var(--text-muted);
    color: var(--text-color);
}

.button-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.btn-employee {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    padding: 2rem 1.5rem;
    border-radius: 12px;
    font-size: var(--text-lg);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.875rem 1.5rem;
    border-radius: 8px;
    font-size: var(--text-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.btn-large {
    width: 100%;
    padding: 1.125rem;
    font-size: var(--text-lg);
    margin-top: 1rem;
}

.btn-submit {
    background: var(--success-color);
}

.btn-submit:hover:not(:disabled) {
    background: #059669;
}

.btn-secondary {
    background: transparent;
    color: var(--danger-color);
    border: 2px solid var(--danger-color);
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-secondary:hover {
    background: var(--danger-color);
    color: white;
}

/* ========== CARDS & SECTIONS ========== */
.add-item-section,
.cart-section,
.summary-section,
.signature-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.add-item-section label,
.signature-section label {
    display: block;
    font-weight: 600;
    font-size: var(--text-sm);
    color: var(--text-color);
    margin-bottom: 0.5rem;
    margin-top: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.add-item-section label:first-child {
    margin-top: 0;
}

/* ========== FORM ELEMENTS ========== */
.large-select {
    width: 100%;
    padding: 0.875rem;
    font-size: var(--text-base);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: white;
    cursor: pointer;
    transition: border-color 0.2s ease;
    font-family: inherit;
}

.large-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.quantity-controls {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

.btn-qty {
    background: var(--primary-color);
    color: white;
    border: none;
    width: 52px;
    height: 52px;
    border-radius: 8px;
    font-size: var(--text-2xl);
    font-weight: 300;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.btn-qty:hover {
    background: var(--primary-hover);
    transform: scale(1.05);
}

.btn-qty:active {
    transform: scale(0.95);
}

#quantity-input {
    flex: 1;
    padding: 0.875rem;
    font-size: var(--text-2xl);
    font-weight: 600;
    text-align: center;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: inherit;
}

#quantity-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

/* ========== CART ========== */
.cart-section h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.cart-section h3::before {
    content: '🛒';
}

.cart-list {
    margin-bottom: 1rem;
}

.empty-cart {
    text-align: center;
    color: var(--text-muted);
    padding: 3rem 1rem;
    font-style: italic;
    font-size: var(--text-sm);
}

.empty-cart::before {
    content: '🛒';
    display: block;
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.3;
}

.cart-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
    margin-bottom: 0.75rem;
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
}

.cart-item:hover {
    box-shadow: var(--shadow-sm);
    border-color: var(--text-muted);
}

.cart-item-info strong {
    font-size: var(--text-base);
    color: var(--text-color);
    display: block;
    margin-bottom: 0.25rem;
}

.cart-item-info span {
    color: var(--text-muted);
    font-size: var(--text-sm);
}

.btn-remove {
    background: var(--danger-color);
    color: white;
    border: none;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    font-size: var(--text-xl);
    cursor: pointer;
    transition: all 0.2s ease;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
}

.btn-remove:hover {
    background: #dc2626;
    transform: scale(1.1);
}

.btn-remove:active {
    transform: scale(0.95);
}

/* ========== SIGNATURE ========== */
.summary-list {
    list-style: none;
    padding-left: 0;
}

.summary-list li {
    padding: 0.875rem 1rem;
    background: var(--bg-color);
    margin-bottom: 0.625rem;
    border-radius: 8px;
    font-size: var(--text-base);
    border-left: 3px solid var(--primary-color);
}

.summary-list li::before {
    content: '✓';
    color: var(--success-color);
    font-weight: bold;
    margin-right: 0.5rem;
}

#signature-pad {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    background: #fafafa;
    display: block;
    width: 100%;
    height: auto;
    max-width: 600px;
    touch-action: none;
    cursor: crosshair;
    transition: border-color 0.2s ease;
}

#signature-pad:hover {
    border-color: var(--primary-color);
    background: white;
}

.signature-controls {
    margin-top: 1rem;
    display: flex;
    gap: 0.75rem;
}

/* ========== CONFIRMATION ========== */
.confirmation-content {
    text-align: center;
    padding: 4rem 1rem;
}

.success-icon {
    font-size: 5rem;
    margin-bottom: 1.5rem;
    animation: bounce 0.6s ease;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.confirmation-content h2 {
    margin-bottom: 1rem;
    color: var(--success-color);
}

.confirmation-content p {
    font-size: var(--text-lg);
    margin-bottom: 0.5rem;
}

.employee-info {
    color: var(--text-muted);
    margin-bottom: 2rem;
    font-size: var(--text-base);
}

/* ========== LOADING OVERLAY ========== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(4px);
    display: none;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    gap: 1.5rem;
    z-index: 1000;
    color: white;
}

.spinner {
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top: 4px solid white;
    border-radius: 50%;
    width: 56px;
    height: 56px;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-overlay p {
    font-size: var(--text-lg);
    font-weight: 500;
}

/* ========== RESPONSIVE ========== */
@media (min-width: 768px) and (orientation: landscape) {
    .button-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .quantity-controls {
        max-width: 400px;
    }
    
    .screen {
        padding: 3rem;
    }
}

@media (max-width: 640px) {
    header h1 {
        font-size: var(--text-xl);
    }
    
    .screen {
        padding: 1.5rem;
    }
    
    .btn-employee {
        padding: 1.5rem 1rem;
        font-size: var(--text-base);
    }
}

/* ========== ACCESSIBILITY ========== */
button:focus-visible,
select:focus-visible,
input:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Prevent text selection on buttons */
button {
    -webkit-user-select: none;
    user-select: none;
}

/* High contrast improvements */
@media (prefers-contrast: high) {
    :root {
        --border-color: #94a3b8;
    }
    
    .btn-employee {
        border-width: 3px;
    }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}