/* --- CSS Reset & Variables (Dark Mode / Fitness Tech Theme) --- */
:root {
    --color-bg: #0F172A; /* Deep Slate / Dark Blue-Black */
    --color-header: #0B1120; /* Very dark, almost black header */
    --color-text-main: #F8FAFC; /* Crisp white for main text */
    --color-text-muted: #94A3B8; /* Cool grey for secondary text */
    --color-heading: #FFFFFF; /* Pure white for headings */
    --color-cta: #3B82F6; /* Bright Electric Blue */
    --color-cta-hover: #2563EB; /* Darker, intense blue on hover */
    --color-footer: #0B1120; /* Dark footer matching header */
    --color-border: #334155; /* Subtle dark grey borders */
    --color-stars: #38BDF8; /* Light blue stars instead of yellow to match theme */
    --color-card-bg: #1E293B; /* Dark grey-blue for content cards */
    
    /* Active border for gallery - Neon Blue Glow */
    --color-gallery-active: #3B82F6; 
}

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

body {
    font-family: 'Inter', sans-serif; /* Modern, readable body font */
    background-color: var(--color-bg);
    color: var(--color-text-main);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
    font-family: 'Montserrat', sans-serif; /* Bold, geometric headings */
    color: var(--color-heading);
    letter-spacing: -0.5px;
}

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

/* --- Layout --- */
.container {
    max-width: 1200px; /* Slightly wider modern layout */
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Header --- */
.site-header {
    background-color: var(--color-header);
    color: #ffffff;
    border-bottom: 2px solid var(--color-border);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.header-container {
    padding: 24px 16px;
    text-align: center;
}

.header-container h1 {
    font-size: 24px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* --- Main Content --- */
.main-content {
    padding-top: 48px;
    padding-bottom: 48px;
}

/* --- Product Section --- */
.product-section {
    background-color: var(--color-card-bg);
    border-radius: 16px; /* Larger border radius for modern feel */
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5); /* Deep shadow for dark mode depth */
    margin-bottom: 56px;
    display: flex;
    flex-direction: column;
    gap: 48px;
}

/* --- Gallery (No JS, Bottom Thumbnails Layout) --- */
.product-media {
    width: 100%;
}

.amazon-gallery {
    display: flex;
    flex-direction: column-reverse; /* Places thumbnails under main image */
    gap: 20px;
}

.gallery-radio {
    display: none;
}

.gallery-thumbnails {
    display: flex;
    flex-direction: row; /* Horizontal layout for bottom placement */
    width: 100%;
    justify-content: center;
    gap: 16px;
    overflow-x: auto;
    padding-bottom: 8px;
}

.thumb-label {
    display: block;
    width: 80px; /* Slightly larger thumbnails */
    aspect-ratio: 1 / 1;
    border: 2px solid transparent;
    border-radius: 12px; /* Smoother rounded corners */
    cursor: pointer;
    overflow: hidden;
    position: relative;
    background-color: #FFFFFF; /* Keep white bg for product images to pop */
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.thumb-label img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 10px;
    padding: 4px;
}

.gallery-main-view {
    position: relative;
    width: 100%;
    aspect-ratio: 1 / 1;
    background-color: #FFFFFF; /* White background for clean product display */
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.main-display {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease-in-out, transform 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: scale(0.98); /* Slight scale effect on switch */
}

.main-display img {
    max-width: 90%;
    max-height: 90%;
    object-fit: contain;
}

/* Gallery State Changes */
#img-1:checked ~ .gallery-main-view .item-1,
#img-2:checked ~ .gallery-main-view .item-2,
#img-3:checked ~ .gallery-main-view .item-3,
#img-4:checked ~ .gallery-main-view .item-4 {
    opacity: 1;
    pointer-events: auto;
    z-index: 2;
    transform: scale(1);
}

#img-1:checked ~ .gallery-thumbnails [for="img-1"],
#img-2:checked ~ .gallery-thumbnails [for="img-2"],
#img-3:checked ~ .gallery-thumbnails [for="img-3"],
#img-4:checked ~ .gallery-thumbnails [for="img-4"] {
    border-color: var(--color-gallery-active);
    box-shadow: 0 0 12px rgba(59, 130, 246, 0.6); /* Neon glow effect */
    transform: translateY(-3px); /* Lifts the active thumbnail slightly */
}

/* --- Product Info --- */
.product-info {
    width: 100%;
    display: flex;
    flex-direction: column;
}

.product-title {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 24px;
    line-height: 1.3;
}

.product-specs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px 12px;
    font-size: 14px;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    padding: 24px 0;
    margin-bottom: 32px;
}

.spec-label {
    font-weight: 500;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-size: 12px;
}

.spec-value {
    font-weight: 600;
    color: var(--color-text-main);
    font-size: 15px;
}

.about-title {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 20px;
}

.about-list {
    padding-left: 24px;
    margin-bottom: 32px;
    color: var(--color-text-muted); /* Softer text for long reading */
}

.about-list li {
    margin-bottom: 16px;
}

.about-list strong {
    color: var(--color-text-main);
}

.seo-keywords {
    font-size: 14px;
    color: var(--color-cta); /* Use accent color to make it pop */
    font-weight: 500;
    background-color: rgba(59, 130, 246, 0.1); /* Transparent blue bg */
    padding: 16px;
    border-radius: 8px;
    border-left: 4px solid var(--color-cta);
}

/* --- CTA Section --- */
.cta-section {
    text-align: center;
    margin-bottom: 64px;
}

.cta-button {
    display: inline-block;
    background-color: var(--color-cta);
    color: #ffffff;
    font-family: 'Montserrat', sans-serif;
    font-size: 18px;
    font-weight: 700;
    text-decoration: none;
    padding: 20px 64px;
    border-radius: 50px; /* Pill shape for modern look */
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1.5px;
}

.cta-button:hover {
    background-color: var(--color-cta-hover);
    box-shadow: 0 8px 25px rgba(59, 130, 246, 0.6);
    transform: translateY(-2px);
}

/* --- Reviews Section --- */
.reviews-section {
    background-color: var(--color-card-bg);
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    max-width: 900px;
    margin: 0 auto 40px auto;
}

.reviews-title {
    font-size: 28px;
    margin-bottom: 40px;
    border-bottom: 2px solid var(--color-border);
    padding-bottom: 20px;
}

.review-item {
    margin-bottom: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid var(--color-border);
}

.review-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.review-author {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 12px;
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
    background-color: var(--color-border);
}

.author-name {
    font-weight: 700;
    font-family: 'Montserrat', sans-serif;
}

.review-rating-title {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 8px;
}

.stars {
    color: var(--color-stars);
    font-size: 20px;
    letter-spacing: 2px;
}

.review-heading {
    font-size: 18px;
    font-weight: 700;
}

.review-meta {
    font-size: 12px;
    color: var(--color-cta); /* Highlighted meta info */
    font-weight: 700;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.review-text {
    color: var(--color-text-muted);
    margin-bottom: 24px;
}

.review-photos {
    display: flex;
    gap: 16px;
}

.review-photo {
    width: 110px;
    height: 110px;
    object-fit: cover;
    border-radius: 12px;
    border: 2px solid var(--color-border);
    transition: transform 0.2s ease;
}

.review-photo:hover {
    transform: scale(1.05);
}

/* --- Footer --- */
.site-footer {
    background-color: var(--color-footer);
    color: var(--color-text-muted);
    padding: 48px 16px;
    text-align: center;
    font-size: 14px;
    border-top: 1px solid var(--color-border);
}

.footer-container {
    max-width: 900px;
    margin: 0 auto;
}

.footer-title {
    color: #ffffff;
    font-family: 'Montserrat', sans-serif;
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 24px;
}

.footer-links {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    margin-bottom: 32px;
}

.footer-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    transition: color 0.2s ease;
    font-weight: 500;
}

.footer-links a:hover {
    color: var(--color-cta);
}

/* --- Media Queries --- */
@media (min-width: 992px) { /* Shifted breakpoint up for wider screens */
    .header-container h1 {
        font-size: 30px;
    }

    .product-section {
        flex-direction: row;
        padding: 56px;
        align-items: flex-start; /* Prevents stretching */
    }

    .product-media {
        width: 45%; /* Slightly narrower image column */
        position: sticky; /* Modern sticky gallery on scroll */
        top: 24px;
    }
    
    .product-info {
        width: 55%;
    }

    .product-title {
        font-size: 32px;
    }

    .footer-links {
        flex-direction: row;
        justify-content: center;
        gap: 40px;
    }
}