:root {
    --primary: #1877F2;
    --primary-hover: #166FE5;
    --bg: #F0F2F5;
    --surface: #FFFFFF;
    --text: #1C1E21;
    --text-secondary: #65676B;
    --border: #E4E6EB;
    --success: #31A24C;
    --danger: #E41E3F;
    --shadow: 0 10px 25px rgba(28, 30, 33, 0.08);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    color: var(--text);
}

img {
    max-width: 100%;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input {
    font: inherit;
}

.container {
    width: min(1200px, calc(100% - 32px));
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 80px;
    gap: 20px;
}

.brand {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: -0.03em;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 18px;
    color: var(--text-secondary);
    font-weight: 600;
}

.main-nav a:hover,
.main-nav a:focus-visible {
    color: var(--primary);
}

.search-form {
    display: flex;
    align-items: center;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 999px;
    overflow: hidden;
    min-width: min(100%, 320px);
}

.search-form input {
    border: none;
    background: transparent;
    padding: 12px 16px;
    width: 100%;
    color: var(--text);
}

.search-form button,
.primary-btn,
.secondary-btn,
.action-btn,
.cart-qty-button,
.delete-btn {
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
}

.search-form button,
.primary-btn,
.secondary-btn,
.action-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    padding: 11px 16px;
    font-weight: 600;
}

.search-form button,
.primary-btn {
    background: var(--primary);
    color: #fff;
}

.search-form button:hover,
.primary-btn:hover,
.primary-btn:focus-visible {
    background: var(--primary-hover);
}

.secondary-btn,
.action-btn {
    background: var(--surface);
    color: var(--primary);
    border: 1px solid var(--border);
}

.secondary-btn:hover,
.action-btn:hover,
.secondary-btn:focus-visible,
.action-btn:focus-visible {
    border-color: var(--primary);
    color: var(--primary-hover);
}

.cart-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--surface);
    padding: 10px 16px;
    border-radius: 999px;
    border: 1px solid var(--border);
    font-weight: 600;
    color: var(--text);
    position: relative;
}

.cart-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
    height: 22px;
    border-radius: 999px;
    padding: 0 6px;
    background: var(--primary);
    color: #fff;
    font-size: 0.76rem;
    font-weight: 700;
}

.page-shell {
    min-height: calc(100vh - 160px);
    padding: 28px 0 48px;
}

.page-header {
    margin-bottom: 24px;
}

.page-heading {
    margin: 0;
    font-size: clamp(2rem, 3vw, 2.6rem);
    letter-spacing: -0.04em;
}

.page-subtitle {
    margin: 10px 0 0;
    color: var(--text-secondary);
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 22px;
}

.product-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.product-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
    background: #eef3ff;
}

.product-body {
    padding: 18px 18px 22px;
}

.product-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 12px;
}

.product-name {
    font-size: 1.15rem;
    font-weight: 700;
    margin: 0;
}

.price {
    font-size: 1.18rem;
    font-weight: 700;
    color: var(--primary);
}

.product-description {
    color: var(--text-secondary);
    line-height: 1.6;
    min-height: 72px;
    margin-bottom: 14px;
}

.product-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 18px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.stock-tag {
    padding: 7px 10px;
    border-radius: 999px;
    font-weight: 700;
    font-size: 0.8rem;
}

.stock-tag.in-stock {
    background: rgba(49, 162, 76, 0.12);
    color: var(--success);
}

.stock-tag.out-of-stock {
    background: rgba(228, 30, 63, 0.12);
    color: var(--danger);
}

.product-actions {
    display: flex;
    gap: 10px;
}

.product-actions .primary-btn,
.product-actions .secondary-btn {
    flex: 1;
}

.flash-message {
    padding: 14px 18px;
    border-radius: 12px;
    margin-bottom: 20px;
    font-weight: 600;
    border: 1px solid transparent;
}

.flash-message.success {
    background: rgba(49, 162, 76, 0.12);
    border-color: rgba(49, 162, 76, 0.22);
    color: #1b6c34;
}

.flash-message.error {
    background: rgba(228, 30, 63, 0.08);
    border-color: rgba(228, 30, 63, 0.2);
    color: var(--danger);
}

.details-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
    gap: 32px;
    align-items: start;
}

.product-visual {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.product-visual img {
    width: 100%;
    height: 440px;
    object-fit: cover;
}

.product-detail-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 24px;
    box-shadow: var(--shadow);
}

.detail-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 18px;
}

.label {
    color: var(--text-secondary);
    font-weight: 600;
    margin-bottom: 8px;
    display: inline-block;
}

.detail-price {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary);
    margin: 10px 0 18px;
}

.detail-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 18px;
}

.detail-quantity {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 14px 0 20px;
}

.detail-quantity input {
    width: 90px;
    padding: 12px 10px;
    border: 1px solid var(--border);
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
}

.cart-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) minmax(260px, 0.7fr);
    gap: 24px;
    align-items: start;
}

.cart-items {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.cart-item {
    display: grid;
    grid-template-columns: 120px minmax(0, 1fr) auto;
    gap: 18px;
    padding: 18px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: var(--shadow);
}

.cart-item img {
    width: 120px;
    height: 120px;
    border-radius: 12px;
    object-fit: cover;
}

.cart-item h3 {
    margin: 0 0 8px;
    font-size: 1.1rem;
}

.cart-item .price-small {
    color: var(--text-secondary);
    margin-bottom: 10px;
}

.cart-controls {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 12px;
}

.cart-qty-button {
    width: 34px;
    height: 34px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1.2rem;
    color: var(--text);
}

.cart-qty-button:hover,
.cart-qty-button:focus-visible {
    border-color: var(--primary);
    color: var(--primary);
}

.qty-value {
    min-width: 34px;
    text-align: center;
    font-weight: 700;
}

.delete-btn {
    background: rgba(228, 30, 63, 0.08);
    color: var(--danger);
    border: 1px solid rgba(228, 30, 63, 0.2);
    border-radius: 10px;
    padding: 8px 12px;
    font-weight: 600;
}

.delete-btn:hover,
.delete-btn:focus-visible {
    background: rgba(228, 30, 63, 0.14);
}

.cart-summary {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 22px;
    box-shadow: var(--shadow);
}

.summary-row {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin: 12px 0;
    color: var(--text-secondary);
}

.summary-row.total {
    margin-top: 18px;
    padding-top: 18px;
    border-top: 1px solid var(--border);
    font-size: 1.15rem;
    color: var(--text);
    font-weight: 700;
}

.order-form {
    display: flex;
    flex-direction: column;
    gap: 14px;
    margin-top: 18px;
}

.order-form label {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-weight: 600;
    color: var(--text-secondary);
}

.order-form input {
    border: 1px solid var(--border);
    background: #fff;
    padding: 12px 14px;
    border-radius: 10px;
}

.order-form input:focus {
    outline: 2px solid rgba(24, 119, 242, 0.15);
    border-color: var(--primary);
}

.empty-state {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 26px;
    text-align: center;
    box-shadow: var(--shadow);
}

.empty-state h2 {
    margin-top: 0;
}

.site-footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 22px 0;
}

.footer-inner {
    text-align: center;
}

@media (max-width: 900px) {
    .header-inner {
        flex-wrap: wrap;
        padding: 16px 0;
    }

    .main-nav,
    .search-form {
        order: 3;
        width: 100%;
    }

    .search-form {
        min-width: auto;
    }

    .details-layout,
    .cart-layout {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .cart-item {
        grid-template-columns: 1fr;
    }

    .product-actions {
        flex-direction: column;
    }

    .product-visual img {
        height: 320px;
    }
}