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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--tg-theme-bg-color, #ffffff);
    color: var(--tg-theme-text-color, #000000);
    overflow-x: hidden;
}

#app {
    min-height: 100vh;
    position: relative;
}

.screen {
    display: none;
    min-height: 100vh;
    padding-bottom: 80px;
}

.screen.active {
    display: block;
}

/* Loading Screen */
#loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}

.loader {
    border: 4px solid var(--tg-theme-hint-color, #f3f3f3);
    border-top: 4px solid var(--tg-theme-button-color, #3390ec);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

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

/* Header */
.header {
    position: sticky;
    top: 0;
    background: var(--tg-theme-bg-color, #ffffff);
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid var(--tg-theme-hint-color, #e0e0e0);
    z-index: 100;
}

.header h2 {
    flex: 1;
    font-size: 18px;
    font-weight: 600;
}

.btn-back {
    background: none;
    border: none;
    font-size: 18px;
    color: var(--tg-theme-button-color, #3390ec);
    cursor: pointer;
    padding: 4px 8px;
}

.btn-cart {
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
    padding: 4px 8px;
}

/* Content */
.content {
    padding: 16px;
}

/* Welcome Screen */
.welcome-content {
    padding: 40px 20px;
    text-align: center;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.welcome-content h1 {
    font-size: 28px;
    margin-bottom: 16px;
}

.welcome-content p {
    font-size: 16px;
    color: var(--tg-theme-hint-color, #999999);
    margin-bottom: 32px;
    line-height: 1.5;
}

/* Buttons */
.button-group {
    display: flex;
    gap: 12px;
    width: 100%;
    max-width: 400px;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: opacity 0.2s;
    flex: 1;
}

.btn:active {
    opacity: 0.7;
}

.btn-primary {
    background: var(--tg-theme-button-color, #3390ec);
    color: var(--tg-theme-button-text-color, #ffffff);
}

.btn-secondary {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    color: var(--tg-theme-text-color, #000000);
}

.btn-danger {
    background: #ff3b30;
    color: #ffffff;
}

.btn-link {
    background: none;
    color: var(--tg-theme-link-color, #3390ec);
    text-decoration: underline;
}

.btn-block {
    width: 100%;
    display: block;
}

/* List */
.list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.list-item {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    border-radius: 12px;
    padding: 16px;
    cursor: pointer;
    transition: transform 0.2s;
}

.list-item:active {
    transform: scale(0.98);
}

.list-item h3 {
    font-size: 16px;
    margin-bottom: 4px;
}

.list-item p {
    font-size: 14px;
    color: var(--tg-theme-hint-color, #999999);
}

/* Product Card */
.product-card {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    border-radius: 12px;
    overflow: hidden;
    margin-bottom: 16px;
}

.product-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--tg-theme-hint-color, #e0e0e0);
}

.product-info {
    padding: 16px;
}

.product-info h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.product-info p {
    font-size: 14px;
    color: var(--tg-theme-hint-color, #999999);
    margin-bottom: 12px;
}

.offer-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px;
    background: var(--tg-theme-bg-color, #ffffff);
    border-radius: 8px;
    margin-bottom: 8px;
}

.offer-item:last-child {
    margin-bottom: 0;
}

.offer-info {
    flex: 1;
}

.offer-name {
    font-weight: 500;
    margin-bottom: 4px;
}

.offer-price {
    color: var(--tg-theme-button-color, #3390ec);
    font-weight: 600;
}

/* Cart */
.cart-item {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 12px;
}

.cart-item-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 8px;
}

.cart-item-name {
    font-weight: 500;
    flex: 1;
}

.cart-item-remove {
    background: #ff3b30;
    color: white;
    border: none;
    border-radius: 4px;
    padding: 4px 8px;
    font-size: 12px;
    cursor: pointer;
}

.cart-item-details {
    font-size: 14px;
    color: var(--tg-theme-hint-color, #999999);
    margin-bottom: 8px;
}

.cart-item-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.quantity-controls {
    display: flex;
    align-items: center;
    gap: 12px;
}

.quantity-btn {
    background: var(--tg-theme-button-color, #3390ec);
    color: white;
    border: none;
    border-radius: 4px;
    width: 32px;
    height: 32px;
    font-size: 18px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

.quantity-value {
    font-weight: 500;
    min-width: 30px;
    text-align: center;
}

.cart-item-subtotal {
    font-weight: 600;
    color: var(--tg-theme-button-color, #3390ec);
}

.cart-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--tg-theme-bg-color, #ffffff);
    padding: 16px;
    border-top: 1px solid var(--tg-theme-hint-color, #e0e0e0);
}

.cart-total {
    font-size: 18px;
    margin-bottom: 12px;
    text-align: center;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
}

.empty-state p {
    font-size: 16px;
    color: var(--tg-theme-hint-color, #999999);
    margin-bottom: 24px;
}

/* Form */
.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--tg-theme-text-color, #000000);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--tg-theme-hint-color, #e0e0e0);
    border-radius: 8px;
    font-size: 16px;
    background: var(--tg-theme-bg-color, #ffffff);
    color: var(--tg-theme-text-color, #000000);
}

.form-group input:focus {
    outline: none;
    border-color: var(--tg-theme-button-color, #3390ec);
}

/* Payment */
.payment-details {
    text-align: center;
    padding: 20px;
}

.payment-qr {
    width: 100%;
    max-width: 300px;
    margin: 20px auto;
    border-radius: 12px;
}

.payment-info {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    border-radius: 12px;
    padding: 16px;
    margin: 16px 0;
}

.payment-info-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
}

.payment-info-item:last-child {
    margin-bottom: 0;
}

.payment-address {
    background: var(--tg-theme-bg-color, #ffffff);
    border: 1px solid var(--tg-theme-hint-color, #e0e0e0);
    border-radius: 8px;
    padding: 12px;
    font-family: monospace;
    font-size: 12px;
    word-break: break-all;
    margin: 12px 0;
}

.payment-status {
    padding: 12px;
    border-radius: 8px;
    margin: 12px 0;
    text-align: center;
    font-weight: 500;
}

.payment-status.pending {
    background: #fff3cd;
    color: #856404;
}

.payment-status.confirmed {
    background: #d4edda;
    color: #155724;
}

.payment-status.expired {
    background: #f8d7da;
    color: #721c24;
}

/* Language Selector */
.language-item {
    background: var(--tg-theme-secondary-bg-color, #f0f0f0);
    border-radius: 12px;
    padding: 16px;
    cursor: pointer;
    transition: transform 0.2s;
    margin-bottom: 12px;
}

.language-item:active {
    transform: scale(0.98);
}

.language-item.active {
    background: var(--tg-theme-button-color, #3390ec);
    color: var(--tg-theme-button-text-color, #ffffff);
}