/* Fast Food POS System - Professional Modern Design */

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f5f7fa;
    color: #2c3e50;
    overflow: hidden;
    height: 100vh;
    font-size: 14px;
}

/* Header Styles - Professional Gradient */
.header {
    background: linear-gradient(135deg, #20bf55 0%, #01baef 100%);
    color: white;
    padding: 12px 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    height: 65px;
    font-size: 13px;
    font-weight: 500;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 30px;
}

.order-info {
    display: flex;
    gap: 20px;
    font-size: 12px;
}

.order-info span {
    background: rgba(255,255,255,0.2);
    padding: 6px 12px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 11px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
}

.header-right {
    display: flex;
    gap: 10px;
}

.nav-btn {
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.2);
    color: white;
    padding: 8px 14px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    backdrop-filter: blur(10px);
}

.nav-btn:hover {
    background: rgba(255,255,255,0.25);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.nav-btn i {
    font-size: 14px;
}

.nav-btn a {
    color: white;
    text-decoration: none;
}

/* Main Layout */
.main-container {
    display: flex;
    height: calc(100vh - 65px);
}

/* Left Sidebar - Cart */
.cart-sidebar {
    width: 560px;
    background: white;
    border-right: 2px solid #e8edf2;
    display: flex;
    flex-direction: column;
    box-shadow: 4px 0 20px rgba(0,0,0,0.08);
}

.cart-header {
    padding: 20px 25px;
    /* border-bottom: 2px solid #f1f5f9; */
    background: linear-gradient(135deg, #20bf55 0%, #1a9f47 100%);
    color: white;
}

.cart-header h3 {
    color: white;
    font-size: 18px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
}

.cart-header p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 14px;
    font-weight: 500;
}

.cart-items {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background: white;
}

.cart-item {
    /* background: #f8fafc; */
    /* padding: 16px; */
    /* margin-bottom: 12px; */
    border-radius: 12px;
    /* border: 2px solid #e2e8f0; */
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.cart-item:hover {
    background: #f1f5f9;
    transform: translateX(3px);
    border-color: #cbd5e1;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.cart-item.selected {
    background: linear-gradient(135deg, #20bf55 0%, #1a9f47 100%);
    color: white;
    border-color: #20bf55;
    box-shadow: 0 6px 20px rgba(32, 191, 85, 0.3);
}

.cart-item.selected .item-name {
    color: white;
}

.cart-item.selected .item-price {
    color: rgba(255,255,255,0.9);
}

.item-details {
    /* display: flex; */
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4px;
}

.item-name {
    font-weight: 600;
    font-size: 15px;
    color: #1e293b;
}

.item-price {
    font-weight: 700;
    color: #20bf55;
    font-size: 16px;
}

.item-quantity {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
}

.quantity-btn {
    background: #20bf55;
    color: white;
    border: none;
    width: 28px;
    height: 28px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: bold;
    font-size: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.quantity-btn:hover {
    background: #1a9f47;
    transform: scale(1.1);
}

.quantity-display {
    font-weight: 600;
    min-width: 24px;
    text-align: center;
    color: #1e293b;
}

.delete-btn {
    background: #ef4444;
    color: white;
    border: none;
    width: 28px;
    height: 28px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-left: auto;
    transition: all 0.3s ease;
}

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

/* Cart controls section */
.cart-controls {
    padding: 20px 25px;
    border-top: 2px solid #f1f5f9;
    background: #f8fafc;
}

.control-labels {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    gap: 10px;
    margin-bottom: 15px;
    font-size: 11px;
    font-weight: 700;
    color: #1e293b;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: #e2e8f0;
    padding: 8px 12px;
    border-radius: 6px;
    text-align: center;
}

.control-labels span {
    padding: 4px 8px;
    border-radius: 4px;
    background: rgba(255, 255, 255, 0.8);
    color: #475569;
    font-weight: 600;
}

.control-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    gap: 10px;
    align-items: center;
    justify-content: center;
}

.control-btn {
    background: #20bf55;
    color: white;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(32, 191, 85, 0.3);
}

.control-btn:hover {
    background: #1a9f47;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(32, 191, 85, 0.4);
}

.control-btn.delete {
    background: #ef4444;
    box-shadow: 0 2px 8px rgba(239, 68, 68, 0.3);
}

.control-btn.delete:hover {
    background: #dc2626;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.4);
}

.quantity-display {
    font-weight: 600;
    min-width: 40px;
    height: 40px;
    text-align: center;
    color: #1e293b;
    background: white;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 700;
}

/* Responsive adjustments for cart controls */
@media (max-width: 1400px) {
    .control-btn {
        width: 35px;
        height: 35px;
        font-size: 14px;
    }
    
    .quantity-display {
        width: 35px;
        height: 35px;
        font-size: 14px;
    }
    
    .control-labels {
        font-size: 10px;
        padding: 6px 10px;
    }
}

@media (max-width: 768px) {
    .cart-controls {
        padding: 15px 20px;
    }
    
    .control-buttons {
        gap: 8px;
    }
    
    .control-btn {
        width: 32px;
        height: 32px;
        font-size: 12px;
    }
    
    .quantity-display {
        width: 32px;
        height: 32px;
        font-size: 12px;
    }
}

/* Empty cart state */
.cart-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: #64748b;
    text-align: center;
    padding: 40px 20px;
}

.cart-empty i {
    font-size: 48px;
    margin-bottom: 20px;
    color: #cbd5e1;
}

.cart-empty h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
    color: #475569;
}

.cart-empty p {
    font-size: 14px;
    color: #64748b;
    line-height: 1.5;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: #f8fafc;
}

.categories-section {
    padding: 4px 8px;
    background: white;
    border-bottom: 2px solid #e8edf2;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(45px, 1fr));
    gap: 4px;
    max-width: 100%;
    overflow-x: auto;
}

.category-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 3px;
    padding: 3px 1px;
    margin: 1px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    min-height: 28px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    pointer-events: auto;
    z-index: 1;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #20bf55 0%, #01baef 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 1;
    pointer-events: none;
}

.category-card:hover {
    border-color: #20bf55;
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(32, 191, 85, 0.2);
}

.category-card.active {
    border-color: #20bf55;
    background: linear-gradient(135deg, #f0fff4 0%, #ecfdf5 100%);
    box-shadow: 0 8px 25px rgba(32, 191, 85, 0.3);
    transform: translateY(-2px);
}

.category-icon {
    font-size: 10px;
    margin-bottom: 1px;
    position: relative;
    z-index: 2;
    pointer-events: none;
}

.category-name {
    font-weight: 400;
    font-size: 6px;
    color: #1e293b;
    text-transform: uppercase;
    letter-spacing: 0.1px;
    position: relative;
    z-index: 2;
    pointer-events: none;
}

/* Items Section */
.items-section {
    flex: 1;
    padding: 3px;
    overflow-y: auto;
}

.items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 6px;
}

.item-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    padding: 4px 3px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.item-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(135deg, #20bf55 0%, #01baef 100%);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.item-card:hover {
    border-color: #20bf55;
    transform: translateY(-4px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.15);
}

.item-card:hover::before {
    transform: scaleX(1);
}

.item-image {
    font-size: 14px;
    margin-bottom: 3px;
}

.item-name {
    font-weight: 400;
    font-size: 7px;
    color: #1e293b;
    margin-bottom: 2px;
    text-transform: uppercase;
    letter-spacing: 0.1px;
}

.item-price {
    font-weight: 500;
    font-size: 9px;
    color: #20bf55;
    margin-bottom: 2px;
}

.item-description {
    font-size: 6px;
    color: #64748b;
    line-height: 1.2;
}

/* Bottom Section */
.bottom-section {
    background: white;
    padding: 20px 25px;
    border-top: 2px solid #e8edf2;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 25px;
    box-shadow: 0 -2px 10px rgba(0,0,0,0.05);
}

.customer-section {
    display: flex;
    gap: 15px;
    align-items: center;
}

.customer-input {
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 14px;
    width: 140px;
    transition: all 0.3s ease;
    background: #f8fafc;
}

.customer-input:focus {
    outline: none;
    border-color: #20bf55;
    background: white;
    box-shadow: 0 0 0 3px rgba(32, 191, 85, 0.1);
}

.select-btn {
    background: linear-gradient(135deg, #20bf55 0%, #1a9f47 100%);
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(32, 191, 85, 0.3);
}

.select-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(32, 191, 85, 0.4);
}

.payment-section {
    text-align: center;
}

.payment-amount {
    font-size: 20px;
    font-weight: 800;
    color: #20bf55;
    margin-bottom: 5px;
}

.items-count {
    font-size: 13px;
    color: #64748b;
    font-weight: 500;
}

.action-buttons {
    display: flex;
    gap: 10px;
}

.action-btn {
    background: #64748b;
    color: white;
    border: none;
    padding: 10px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.action-btn:hover {
    background: #475569;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

/* Right Sidebar */
.right-sidebar {
    width: 80px;
    background: linear-gradient(180deg, #01baef 0%, #00a8d4 100%);
    border-left: 2px solid #0099c7;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 15px 0;
    gap: 8px;
    box-shadow: -4px 0 20px rgba(1, 186, 239, 0.2);
    position: relative;
    z-index: 10;
}

.sidebar-btn {
    width: 60px;
    height: 60px;
    border: none;
    border-radius: 8px;
    background: transparent;
    color: white;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin: 2px 0;
    position: relative;
    outline: none;
}

.sidebar-btn i {
    font-size: 20px;
    margin-bottom: 4px;
    display: block;
}

.sidebar-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.2);
}

.sidebar-btn.active {
    background: rgba(255, 255, 255, 0.2);
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.3);
}

.sidebar-btn::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: white;
    transition: width 0.3s ease;
}

.sidebar-btn:hover::after,
.sidebar-btn.active::after {
    width: 30px;
}

/* Modal improvements */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: white;
    border-radius: 16px;
    padding: 30px;
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    position: relative;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid #f1f5f9;
}

.modal-title {
    font-size: 20px;
    font-weight: 700;
    color: #1e293b;
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 24px;
    color: #64748b;
    cursor: pointer;
    padding: 5px;
    border-radius: 6px;
    transition: all 0.3s ease;
}

.modal-close:hover {
    background: #f1f5f9;
    color: #1e293b;
}

/* Form Styles */
.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: #1e293b;
    font-size: 14px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    font-size: 14px;
    transition: all 0.3s ease;
    background: #f8fafc;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #20bf55;
    background: white;
    box-shadow: 0 0 0 3px rgba(32, 191, 85, 0.1);
}

.form-actions {
    display: flex;
    gap: 15px;
    justify-content: flex-end;
    margin-top: 25px;
    padding-top: 25px;
    border-top: 2px solid #f1f5f9;
}

/* Button improvements */
.btn {
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 14px;
}

.btn-primary {
    background: linear-gradient(135deg, #20bf55 0%, #1a9f47 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(32, 191, 85, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, #1a9f47 0%, #15803d 100%);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(32, 191, 85, 0.4);
}

.btn-secondary {
    background: #64748b;
    color: white;
    box-shadow: 0 4px 12px rgba(100, 116, 139, 0.3);
}

.btn-secondary:hover {
    background: #475569;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(100, 116, 139, 0.4);
}

.btn-danger {
    background: #ef4444;
    color: white;
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
}

.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(239, 68, 68, 0.4);
}

.btn-outline {
    background: transparent;
    border: 2px solid #e2e8f0;
    color: #64748b;
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    font-size: 14px;
}

.btn-outline:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
    color: #475569;
}

/* Table selection grid */
.table-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
    margin: 20px 0;
}

.table-btn {
    padding: 15px 10px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    background: white;
    color: #1e293b;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.table-btn:hover {
    border-color: #20bf55;
    background: #f0fdf4;
    transform: scale(1.05);
}

.table-btn.selected {
    border-color: #20bf55;
    background: #20bf55;
    color: white;
}

/* QR Code styling */
.qr-code {
    text-align: center;
    margin: 20px 0;
    padding: 20px;
    background: #f8fafc;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
}

.qr-code img {
    max-width: 150px;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

/* Payment modal improvements */
.payment-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin: 20px 0;
}

.payment-option {
    padding: 20px;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    font-weight: 600;
    font-size: 16px;
}

.payment-option:hover {
    border-color: #20bf55;
    background: #f0fdf4;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(32, 191, 85, 0.2);
}

.payment-option.selected {
    border-color: #20bf55;
    background: #20bf55;
    color: white;
}

/* Responsive improvements */
@media (max-width: 1400px) {
    .sidebar-btn {
        width: 55px;
        height: 55px;
        font-size: 11px;
    }
    .sidebar-btn i {
        font-size: 18px;
    }
}

@media (max-width: 768px) {
    .right-sidebar {
        width: 100%;
        height: 80px;
        flex-direction: row;
        justify-content: center;
        padding: 10px 0;
    }
    .sidebar-btn {
        width: 50px;
        height: 50px;
        font-size: 10px;
        margin: 0 5px;
    }
    .sidebar-btn i {
        font-size: 16px;
        margin-bottom: 2px;
    }
    .modal-content {
        margin: 20px;
        padding: 20px;
    }
    .payment-options {
        grid-template-columns: 1fr;
    }
    .table-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .categories-grid {
        grid-template-columns: repeat(auto-fit, minmax(50px, 1fr));
        gap: 4px;
    }
    
    .category-card {
        min-height: 35px;
        padding: 3px 2px;
    }
    
    .category-icon {
        font-size: 10px;
        margin-bottom: 1px;
    }
    
    .category-name {
        font-size: 6px;
    }
    
    .items-grid {
        grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
        gap: 6px;
    }
    
    .item-card {
        padding: 4px 3px;
    }
    
    .item-image {
        font-size: 14px;
        margin-bottom: 3px;
    }
    
    .item-name {
        font-size: 7px;
        margin-bottom: 2px;
    }
    
    .item-price {
        font-size: 8px;
        margin-bottom: 2px;
    }
    
    .item-description {
        font-size: 6px;
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f5f9;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #94a3b8;
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 24px;
    height: 24px;
    border: 3px solid #f1f5f9;
    border-top: 3px solid #20bf55;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Toast Notifications */
.toast {
    position: fixed;
    top: 25px;
    right: 25px;
    padding: 16px 24px;
    border-radius: 12px;
    color: white;
    font-weight: 600;
    z-index: 1000;
    transform: translateX(100%);
    transition: transform 0.3s ease;
    max-width: 350px;
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
    backdrop-filter: blur(10px);
}

.toast.show {
    transform: translateX(0);
}

.toast.success {
    background: linear-gradient(135deg, #20bf55 0%, #1a9f47 100%);
}

.toast.error {
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
}

.toast.warning {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    color: white;
}

.toast.info {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
} 

/* Calculator specific styles */
.calculator-display {
    background: #f8fafc;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    padding: 15px;
    font-size: 24px;
    text-align: right;
    color: #1e293b;
    font-family: 'Courier New', monospace;
    width: 100%;
    margin-bottom: 20px;
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    margin-bottom: 15px;
}

.calculator-btn {
    padding: 15px;
    font-size: 18px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.calculator-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.calculator-btn.number {
    background: #f8fafc;
    color: #1e293b;
    border: 2px solid #e2e8f0;
}

.calculator-btn.number:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
}

.calculator-btn.operator {
    background: #3b82f6;
    color: white;
    border: 2px solid #3b82f6;
}

.calculator-btn.operator:hover {
    background: #2563eb;
    border-color: #2563eb;
}

.calculator-btn.equals {
    background: #10b981;
    color: white;
    border: 2px solid #10b981;
}

.calculator-btn.equals:hover {
    background: #059669;
    border-color: #059669;
}

.calculator-btn.clear {
    background: #ef4444;
    color: white;
    border: 2px solid #ef4444;
}

.calculator-btn.clear:hover {
    background: #dc2626;
    border-color: #dc2626;
}

.calculator-btn.backspace {
    background: #f59e0b;
    color: white;
    border: 2px solid #f59e0b;
}

.calculator-btn.backspace:hover {
    background: #d97706;
    border-color: #d97706;
}

/* Quick amount buttons */
.quick-amount-btn {
    background: #f8fafc;
    border: 2px solid #e2e8f0;
    color: #64748b;
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    font-size: 14px;
}

.quick-amount-btn:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
    color: #475569;
}

/* Responsive calculator */
@media (max-width: 768px) {
    .calculator-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 6px;
    }
    
    .calculator-btn {
        padding: 12px;
        font-size: 16px;
    }
    
    .calculator-display {
        font-size: 20px;
        padding: 12px;
    }
}