/* Nike Design System - Mobile First */
:root {
    /* Colors */
    --color-primary: #111111;
    --color-on-primary: #ffffff;
    --color-canvas: #ffffff;
    --color-soft-cloud: #f5f5f5;
    --color-ink: #111111;
    --color-charcoal: #39393b;
    --color-ash: #4b4b4d;
    --color-mute: #707072;
    --color-stone: #9e9ea0;
    --color-hairline: #cacacb;
    --color-hairline-soft: #e5e5e5;
    --color-sale: #d30005;
    --color-success: #007d48;

    /* Spacing - Mobile First */
    --spacing-xxs: 2px;
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 18px;
    --spacing-xl: 24px;
    --spacing-xxl: 30px;
    --spacing-section: 48px;

    /* Border Radius */
    --rounded-none: 0px;
    --rounded-sm: 18px;
    --rounded-md: 24px;
    --rounded-lg: 30px;
    --rounded-full: 9999px;
}

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

body {
    font-family: 'Helvetica Now Text', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    font-weight: 400;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--color-ink);
    background: var(--color-canvas);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

@media (min-width: 768px) {
    body {
        font-size: 16px;
    }
}

.container {
    width: 100%;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-lg);
    }
}

@media (min-width: 1024px) {
    .container {
        max-width: 1440px;
        padding: 0 var(--spacing-xl);
    }
}

/* Global Navigation */
header {
    background: var(--color-canvas);
    color: var(--color-ink);
    height: 56px;
    margin-bottom: 30px;;
    height: 100%;
    border-bottom: 1px solid var(--color-hairline-soft);
}

header nav {
    display: flex;
    align-items: center;
    height: 100%;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    position: relative;
}

.logo {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 18px;
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: 0;
    color: var(--color-ink);
    text-decoration: none;
    transition: opacity 0.3s;
    text-transform: uppercase;
}

@media (min-width: 768px) {
    .logo {
        font-size: 24px;
    }
}

.logo:hover {
    opacity: 0.8;
}

/* Burger Menu */
.burger-menu {
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    width: 30px;
    height: 25px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1001;
}

.burger-menu span {
    width: 30px;
    height: 3px;
    background: var(--color-ink);
    border-radius: 2px;
    transition: all 0.3s ease;
    transform-origin: center;
}

.burger-menu.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.burger-menu.active span:nth-child(2) {
    opacity: 0;
}

.burger-menu.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

@media (min-width: 768px) {
    .burger-menu {
        display: none;
    }
}

.nav-menu {
    display: none;
    list-style: none;
    gap: var(--spacing-md);
    align-items: center;
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--color-canvas);
    flex-direction: column;
    padding: var(--spacing-xl) 0;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.nav-menu.active {
    display: flex;
}

@media (min-width: 768px) {
    .nav-menu {
        display: flex;
        position: static;
        flex-direction: row;
        padding: 0;
        box-shadow: none;
        gap: var(--spacing-xl);
    }
}

.nav-menu a {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 16px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--color-ink);
    text-decoration: none;
    transition: opacity 0.3s;
    padding: var(--spacing-sm) 0;
}

@media (min-width: 768px) {
    .nav-menu a {
        font-size: 16px;
        padding: 0;
    }
}

.nav-menu a:hover {
    opacity: 0.7;
}

/* Scroll to Top Button */
.scroll-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--color-ink);
    color: var(--color-on-primary);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
    z-index: 999;
}

.scroll-to-top:hover {
    background: var(--color-charcoal);
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
}

.scroll-to-top:active {
    transform: translateY(-1px);
}

.scroll-to-top.visible {
    display: flex;
}

@media (max-width: 767px) {
    .scroll-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
        font-size: 20px;
    }
}

main {
    flex: 1;
}

main h1 {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 24px;
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: 0;
    color: var(--color-ink);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    main h1 {
        font-size: 32px;
    }
}

/* Footer */
footer {
    background: var(--color-canvas);
    color: var(--color-mute);
    padding: var(--spacing-section) 0;
    margin-top: auto;
    border-top: 1px solid var(--color-hairline);
}

footer .container {
    text-align: center;
}

footer p {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
}

/* Typography Utilities */
.display-lg {
    font-family: 'SF Pro Display', system-ui, -apple-system, sans-serif;
    font-size: 40px;
    font-weight: 600;
    line-height: 1.1;
    letter-spacing: 0;
}

.tagline {
    font-family: 'SF Pro Display', system-ui, -apple-system, sans-serif;
    font-size: 21px;
    font-weight: 600;
    line-height: 1.19;
    letter-spacing: 0.231px;
}

.body-strong {
    font-weight: 600;
    line-height: 1.24;
}

.caption {
    font-size: 14px;
    font-weight: 400;
    line-height: 1.43;
    letter-spacing: -0.224px;
}

/* Buttons */
.btn {
    display: inline-block;
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    padding: 12px 24px;
    height: 44px;
    background: var(--color-ink);
    color: var(--color-on-primary);
    text-decoration: none;
    border-radius: var(--rounded-lg);
    border: none;
    cursor: pointer;
    transition: transform 0.2s, opacity 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
}

@media (min-width: 768px) {
    .btn {
        font-size: 16px;
        height: 48px;
        width: auto;
    }
}

.btn:hover {
    opacity: 0.8;
}

.btn:active {
    transform: scale(0.95);
    opacity: 0.5;
}

.btn-secondary {
    background: var(--color-soft-cloud);
    color: var(--color-ink);
}

.btn-secondary:hover {
    opacity: 0.8;
}

.btn-primary {
    background: var(--color-ink);
    color: var(--color-on-primary);
}

/* Products Section */
.products-section {
    padding: var(--spacing-section) 0;
}

.categories-filter {
    display: flex;
    gap: var(--spacing-sm);
    margin: var(--spacing-xxl) 0;
    flex-wrap: wrap;
}

.category-btn {
    padding: 8px 16px;
    background: var(--color-canvas);
    color: var(--color-ink);
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 16px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    text-decoration: none;
    border-radius: var(--rounded-lg);
    border: 1px solid var(--color-hairline);
    transition: all 0.2s;
}

.category-btn:hover {
    opacity: 0.8;
}

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

.category-btn.active {
    background: var(--color-ink);
    border-color: var(--color-ink);
    color: var(--color-on-primary);
}

/* Products Grid */
.products-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin: var(--spacing-xxl) 0;
}

@media (min-width: 600px) {
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .products-grid {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    }
}

.product-card {
    background: var(--color-canvas);
    border: none;
    border-radius: var(--rounded-none);
    overflow: hidden;
    transition: opacity 0.2s;
}

.product-card:hover {
    opacity: 0.8;
}

.product-image {
    width: 100%;
    height: 200px;
    background: var(--color-soft-cloud);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
}

@media (min-width: 768px) {
    .product-image {
        height: 280px;
        padding: var(--spacing-xl);
    }
}

.product-image img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.product-info {
    padding: var(--spacing-md);
}

@media (min-width: 768px) {
    .product-info {
        padding: var(--spacing-lg);
    }
}

.product-info h3 {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--color-ink);
    margin-bottom: var(--spacing-xs);
}

@media (min-width: 768px) {
    .product-info h3 {
        font-size: 16px;
    }
}

.product-description {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: var(--color-mute);
    font-size: 12px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    margin-bottom: var(--spacing-md);
}

@media (min-width: 768px) {
    .product-description {
        font-size: 14px;
    }
}

.product-price {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--color-ink);
    margin-bottom: var(--spacing-md);
}

@media (min-width: 768px) {
    .product-price {
        font-size: 16px;
    }
}

/* Product Detail Page */
.breadcrumbs {
    padding: var(--spacing-lg) 0;
    font-size: 12px;
    color: var(--color-ink-muted-48);
}

.breadcrumbs a {
    color: var(--color-primary);
    text-decoration: none;
    transition: opacity 0.3s;
}

.breadcrumbs a:hover {
    opacity: 0.7;
}

.product-detail {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl) 0;
}

@media (min-width: 768px) {
    .product-detail {
        gap: var(--spacing-xxl);
        padding: var(--spacing-xxl) 0;
    }
}

@media (min-width: 1024px) {
    .product-detail {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-section);
    }
}

.product-detail-image {
    width: 100%;
    height: 300px;
    background: var(--color-soft-cloud);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--rounded-none);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .product-detail-image {
        height: 400px;
        padding: var(--spacing-xl);
    }
}

@media (min-width: 1024px) {
    .product-detail-image {
        height: 500px;
        padding: var(--spacing-xxl);
    }
}

.product-detail-image img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

/* Image Carousel */
.product-carousel {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

@media (min-width: 768px) {
    .product-carousel {
        grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
        gap: var(--spacing-sm);
        margin-top: var(--spacing-lg);
    }
}

.carousel-thumb {
    width: 100%;
    height: 60px;
    background: var(--color-soft-cloud);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border: 2px solid transparent;
    transition: border-color 0.2s;
    padding: var(--spacing-xs);
}

@media (min-width: 768px) {
    .carousel-thumb {
        height: 80px;
    }
}

.carousel-thumb:hover {
    border-color: var(--color-hairline);
}

.carousel-thumb.active {
    border-color: var(--color-ink);
}

.carousel-thumb img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.product-detail-info h1 {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 24px;
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: 0;
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .product-detail-info h1 {
        font-size: 32px;
    }
}

.product-category {
    font-family: 'Helvetica Now Text Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 12px;
    font-weight: 500;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--color-mute);
    margin-bottom: var(--spacing-md);
}

@media (min-width: 768px) {
    .product-category {
        font-size: 14px;
    }
}

.product-category a {
    color: var(--color-ink);
    text-decoration: underline;
    transition: opacity 0.3s;
}

.product-category a:hover {
    opacity: 0.7;
}

.product-short-description {
    font-size: 16px;
    font-weight: 400;
    line-height: 1.5;
    color: var(--color-charcoal);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .product-short-description {
        font-size: 18px;
    }
}

.product-price-large {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 20px;
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: 0;
    color: var(--color-ink);
    margin: var(--spacing-lg) 0;
}

@media (min-width: 768px) {
    .product-price-large {
        font-size: 24px;
        margin: var(--spacing-xl) 0;
    }
}

.product-full-description {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--color-hairline-soft);
}

@media (min-width: 768px) {
    .product-full-description {
        margin-top: var(--spacing-xxl);
        padding-top: var(--spacing-xxl);
    }
}

.product-full-description p {
    color: var(--color-charcoal);
    line-height: 1.6;
}

.product-faq {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--color-hairline-soft);
}

@media (min-width: 768px) {
    .product-faq {
        margin-top: var(--spacing-xxl);
        padding-top: var(--spacing-xxl);
    }
}

/* Hero Section */
.hero-section {
    background: var(--color-canvas);
    padding: var(--spacing-xxl) 0;
    text-align: center;
}

@media (min-width: 768px) {
    .hero-section {
        padding: var(--spacing-section) 0;
    }
}

.hero-section h1 {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 32px;
    font-weight: 500;
    line-height: 0.9;
    letter-spacing: 0;
    text-transform: uppercase;
    color: var(--color-ink);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 600px) {
    .hero-section h1 {
        font-size: 48px;
    }
}

@media (min-width: 768px) {
    .hero-section h1 {
        font-size: 64px;
    }
}

@media (min-width: 1024px) {
    .hero-section h1 {
        font-size: 96px;
        margin-bottom: var(--spacing-xl);
    }
}

.hero-section p {
    font-family: 'Helvetica Now Display Medium', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 16px;
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: 0;
    color: var(--color-ink);
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .hero-section p {
        font-size: 20px;
    }
}

@media (min-width: 1024px) {
    .hero-section p {
        font-size: 24px;
        margin-bottom: var(--spacing-xl);
    }
}

.hero-cta {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    justify-content: center;
    align-items: center;
    width: 100%;
}

@media (min-width: 768px) {
    .hero-cta {
        flex-direction: row;
        width: auto;
    }
}

/* Responsive */
@media (min-width: 320px) {
    .product-detail-image {
        min-height: 250px;
    }
}

/* Mobile responsive for index page sections */
@media (max-width: 767px) {
    /* Hero section mobile */
    .hero-section > .container > div[style*="display: grid"] {
        grid-template-columns: 1fr !important;
        gap: 24px !important;
    }

    .hero-section h1 {
        font-size: 32px !important;
    }

    .hero-section p {
        font-size: 16px !important;
    }

    .hero-section > .container > div > div:first-child > div {
        flex-direction: column !important;
    }

    /* Practical Help section mobile */
    section div[style*="grid-template-columns: repeat(3, 1fr)"] {
        grid-template-columns: 1fr !important;
    }

    /* Pet Hair Type Solutions mobile */
    section div[style*="grid-template-columns: repeat(auto-fit, minmax(280px, 1fr))"] {
        grid-template-columns: 1fr !important;
    }
}