/**
 * Oura Ring 4 - Exclusive Premium CSS Architecture
 * Main Theme Palette: Deep Tech Blue and Metallic Gold/Yellow Accent.
 * Tailored exclusively for responsive performance, beautiful glassmorphism gradients, 
 * pure CSS interactions, and advanced typographic styling.
 */

/* -------------------------------------------------------------
   01. DESIGN SYSTEM VARIABLES & ROOT ARCHITECTURE
   ------------------------------------------------------------- */
:root {
    /* Color Palette Master Values */
    --color-primary-deep: #0a1931;       /* Deep Rich Navy Blue */
    --color-primary-medium: #15305b;     /* Medium Slate Tech Blue */
    --color-primary-light: #1f4277;      /* Vivid Sky Navy Accent */
    --color-primary-glow: #2c5da1;       /* Ambient Electric Blue Glow */
    
    --color-accent-gold: #ffc93c;        /* Vibrant Sun Yellow / Gold Accent */
    --color-accent-gold-hover: #e0af2f;  /* Darker Rich Gold for Interactive States */
    --color-accent-gold-light: #ffebd3;  /* Warm Pastel Yellow Tint */
    
    --color-neutral-dark: #121824;       /* Soft Tech Charcoal Black */
    --color-neutral-gray-800: #1e293b;   /* Modern Anthracite Gray */
    --color-neutral-gray-600: #475569;   /* Slate Gray for Secondary Copy */
    --color-neutral-gray-400: #94a3b8;   /* Cool Gray for Borders and Muted Elements */
    --color-neutral-gray-100: #f1f5f9;   /* Pure Frost Light Gray Gray Backgrounds */
    --color-neutral-pure-white: #ffffff; /* Absolute White */
    
    /* Advanced Layered Box Shadows */
    --shadow-level-1: 0 2px 4px rgba(10, 25, 49, 0.04);
    --shadow-level-2: 0 4px 12px rgba(10, 25, 49, 0.06), 0 1px 3px rgba(10, 25, 49, 0.02);
    --shadow-level-3: 0 12px 24px rgba(10, 25, 49, 0.08), 0 4px 8px rgba(10, 25, 49, 0.04);
    --shadow-level-4: 0 24px 48px rgba(10, 25, 49, 0.12), 0 8px 16px rgba(10, 25, 49, 0.06);
    --shadow-premium-glow: 0 0 30px rgba(255, 201, 60, 0.25);
    --shadow-blue-glow: 0 0 40px rgba(44, 93, 161, 0.15);
    
    /* Layout Constants */
    --border-radius-sm: 6px;
    --border-radius-md: 12px;
    --border-radius-lg: 20px;
    --border-radius-xl: 32px;
    --default-transition: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
    --fast-transition: all 0.2s ease-in-out;
}

/* -------------------------------------------------------------
   02. BODY & GENERAL RESET LAYOUTS
   ------------------------------------------------------------- */
body.custom-body {
    background-color: var(--color-neutral-pure-white);
    color: var(--color-neutral-dark);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.6;
    letter-spacing: -0.011em;
}

/* Custom Selection Highlight */
::selection {
    background-color: var(--color-accent-gold-light);
    color: var(--color-primary-deep);
}

/* -------------------------------------------------------------
   03. DECORATIVE TOP BAR & PREMIUM ELEMENTS
   ------------------------------------------------------------- */
.top-premium-bar {
    height: 5px;
    width: 100%;
    background: linear-gradient(90deg, var(--color-primary-deep) 0%, var(--color-primary-light) 40%, var(--color-accent-gold) 75%, var(--color-accent-gold-hover) 100%);
    position: relative;
    z-index: 100;
}

/* -------------------------------------------------------------
   04. ULTRA-MODERN GLASSMORPHIC STICKY HEADER
   ------------------------------------------------------------- */
.custom-header {
    height: 70px;
    background-color: rgba(10, 25, 49, 0.94);
    border-bottom: 2px solid var(--color-accent-gold);
    box-shadow: var(--shadow-level-3);
    overflow: hidden;
    transition: var(--default-transition);
}

.header-blur-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 1;
}

.header-left-decor {
    position: relative;
    z-index: 5;
}

.decor-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--color-accent-gold);
    display: inline-block;
    box-shadow: 0 0 8px var(--color-accent-gold);
    animation: pulseGlow 2s infinite ease-in-out;
}

.decor-text {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--color-neutral-pure-white);
    letter-spacing: 0.15em;
    opacity: 0.8;
}

.header-center-title {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    z-index: 5;
    text-align: center;
    white-space: nowrap;
}

.brand-main-text {
    font-family: 'Playfair Display', Georgia, serif;
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #ffffff 0%, #fefefe 50%, var(--color-accent-gold) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
}

.header-right-decor {
    position: relative;
    z-index: 5;
}

.badge-premium {
    font-size: 10px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    background-color: rgba(255, 201, 60, 0.15);
    color: var(--color-accent-gold);
    border: 1px solid rgba(255, 201, 60, 0.4);
    padding: 4px 12px;
    border-radius: 50px;
    box-shadow: inset 0 1px 4px rgba(255,255,255,0.1);
}

/* -------------------------------------------------------------
   05. AMBIENT BACKGROUND GLOW BLOBS
   ------------------------------------------------------------- */
.bg-glow-blob-1 {
    position: absolute;
    width: 450px;
    height: 450px;
    top: 15%;
    left: -150px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(44, 93, 161, 0.08) 0%, rgba(255,255,255,0) 70%);
    z-index: -1;
    pointer-events: none;
}

.bg-glow-blob-2 {
    position: absolute;
    width: 500px;
    height: 500px;
    top: 45%;
    right: -200px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 201, 60, 0.05) 0%, rgba(255,255,255,0) 70%);
    z-index: -1;
    pointer-events: none;
}

/* -------------------------------------------------------------
   06. PRODUCT HERO SECTION & CARD CONTAINER
   ------------------------------------------------------------- */
.product-hero-section {
    padding-top: 40px;
    padding-bottom: 40px;
    position: relative;
}

.premium-product-card {
    background-color: var(--color-neutral-pure-white);
    border-radius: var(--border-radius-lg);
    border: 1px solid rgba(15, 32, 67, 0.06);
    box-shadow: var(--shadow-level-4), var(--shadow-blue-glow);
    padding: 24px;
    transition: var(--default-transition);
}

.premium-product-card:hover {
    box-shadow: 0 35px 70px rgba(10, 25, 49, 0.14), 0 0 50px rgba(44, 93, 161, 0.08);
}

/* Geometric Corner Accents */
.corner-accent {
    position: absolute;
    width: 14px;
    height: 14px;
    border: 2px solid transparent;
    z-index: 5;
    opacity: 0.4;
    pointer-events: none;
}
.corner-tl { top: 16px; left: 16px; border-top-color: var(--color-primary-light); border-left-color: var(--color-primary-light); }
.corner-tr { top: 16px; right: 16px; border-top-color: var(--color-primary-light); border-right-color: var(--color-primary-light); }
.corner-bl { bottom: 16px; left: 16px; border-bottom-color: var(--color-primary-light); border-left-color: var(--color-primary-light); }
.corner-br { bottom: 16px; right: 16px; border-bottom-color: var(--color-primary-light); border-right-color: var(--color-primary-light); }

/* -------------------------------------------------------------
   07. INTERACTIVE CSS-ONLY PHOTO GALLERY ARCHITECTURE
   ------------------------------------------------------------- */
.gallery-wrapper-panel {
    position: relative;
    width: 100%;
}

.gallery-interactive-container {
    width: 100%;
    position: relative;
}

/* Main Display Frame Styling */
.premium-image-viewframe {
    width: 100%;
    height: 320px;
    background-color: #fafbfc;
    border: 1px solid rgba(10, 25, 49, 0.08);
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: inset 0 2px 8px rgba(10, 25, 49, 0.02);
}

.viewframe-inner-glow {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    box-shadow: inset 0 0 20px rgba(10, 25, 49, 0.03);
    pointer-events: none;
    z-index: 10;
}

/* Core Slides Configurations */
.gallery-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    visibility: hidden;
    transform: scale(0.97);
    transition: opacity 0.45s ease-in-out, transform 0.45s cubic-bezier(0.25, 0.46, 0.45, 0.94), visibility 0.45s;
    z-index: 2;
}

.slide-media-holder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
}

.gallery-core-img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    filter: drop-shadow(0 8px 16px rgba(10, 25, 49, 0.08));
    transition: var(--default-transition);
}

/* Toggle Logic Maps from Radio States */
#gallery-radio-1:checked ~ .premium-image-viewframe .slide-index-1,
#gallery-radio-2:checked ~ .premium-image-viewframe .slide-index-2,
#gallery-radio-3:checked ~ .premium-image-viewframe .slide-index-3,
#gallery-radio-4:checked ~ .premium-image-viewframe .slide-index-4 {
    opacity: 1;
    visibility: visible;
    transform: scale(1);
    z-index: 5;
}

/* Thumbnails Grid Setup */
.thumbnails-navigation-grid {
    position: relative;
    z-index: 20;
}

.thumb-nav-item {
    background-color: var(--color-neutral-pure-white);
    border: 2px solid rgba(10, 25, 49, 0.06);
    border-radius: var(--border-radius-sm);
    padding: 4px;
    height: 70px;
    box-shadow: var(--shadow-level-1);
    transform: translateY(0);
}

.thumb-nav-item:hover {
    border-color: var(--color-primary-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow-level-2);
}

.thumb-image-wrapper {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    border-radius: 4px;
    background-color: #fafbfc;
}

.thumb-img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    transition: var(--fast-transition);
}

.thumb-nav-item:hover .thumb-img {
    transform: scale(1.06);
}

/* Active Highlight Radio Filters */
#gallery-radio-1:checked ~ .thumbnails-navigation-grid .thumb-nav-1,
#gallery-radio-2:checked ~ .thumbnails-navigation-grid .thumb-nav-2,
#gallery-radio-3:checked ~ .thumbnails-navigation-grid .thumb-nav-3,
#gallery-radio-4:checked ~ .thumbnails-navigation-grid .thumb-nav-4 {
    border-color: var(--color-primary-deep);
    box-shadow: 0 0 0 3px rgba(10, 25, 49, 0.12), var(--shadow-level-2);
    transform: scale(0.96);
    background-color: rgba(10, 25, 49, 0.02);
}

/* -------------------------------------------------------------
   08. RIGHT COLUMN: PRODUCT INFORMATION & TYPOGRAPHY
   ------------------------------------------------------------- */
.product-narrative-panel {
    width: 100%;
}

.badge-category-tag {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-primary-deep);
    background-color: rgba(10, 25, 49, 0.05);
    padding: 3px 10px;
    border-radius: 4px;
}

.main-product-heading {
    font-size: 32px;
    font-weight: 800;
    color: var(--color-primary-deep);
    letter-spacing: -0.025em;
    line-height: 1.15;
}

.heading-decorative-line {
    display: block;
    width: 60px;
    height: 4px;
    background-color: var(--color-accent-gold);
    margin-top: 12px;
    border-radius: 2px;
    box-shadow: 0 1px 3px rgba(255, 201, 60, 0.4);
}

.section-sub-title {
    font-size: 12px;
    letter-spacing: 0.12em;
    color: var(--color-primary-medium);
    border-left: 3px solid var(--color-primary-deep);
    padding-left: 8px;
}

/* Advanced Features List Stack Formatting */
.feature-structured-stack {
    width: 100%;
}

.feature-item-card {
    background-color: rgba(248, 250, 252, 0.65);
    border: 1px solid rgba(15, 32, 67, 0.04);
    border-radius: var(--border-radius-md);
    padding: 16px;
    box-shadow: var(--shadow-level-1);
    overflow: hidden;
}

.feature-item-card:hover {
    background-color: rgba(248, 250, 252, 1);
    border-color: rgba(15, 32, 67, 0.08);
    box-shadow: var(--shadow-level-2);
    transform: translateX(4px);
}

.custom-checkmark-icon {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background-color: var(--color-primary-deep);
    color: var(--color-accent-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 2px;
    margin-right: 14px;
    box-shadow: 0 2px 6px rgba(10, 25, 49, 0.15);
}

.checkmark-symbol {
    font-size: 12px;
    font-weight: 800;
}

/* Keywords Compliance Box styling */
.mandatory-keywords-premium-box {
    background-color: rgba(255, 24beb3, 60, 0.07);
    border: 1px dashed rgba(255, 201, 60, 0.6);
    box-shadow: inset 0 1px 4px rgba(255, 201, 60, 0.04);
}

.keywords-icon-wrapper {
    font-size: 14px;
    line-height: 1;
    animation: simpleSpin 8s infinite linear;
}

/* -------------------------------------------------------------
   09. MEGA CENTRALIZED CTA BLOCK DESIGN
   ------------------------------------------------------------- */
.mega-cta-section {
    margin-top: 48px;
    margin-bottom: 48px;
}

.cta-section-panel-card {
    background: linear-gradient(135deg, var(--color-primary-deep) 0%, var(--color-primary-medium) 100%);
    box-shadow: var(--shadow-level-4), 0 20px 40px rgba(10, 25, 49, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

/* Decorative Background Elements for CTA Panel */
.cta-decor-circle-1 {
    position: absolute;
    width: 280px;
    height: 280px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 201, 60, 0.06) 0%, rgba(255,255,255,0) 70%);
    top: -100px;
    right: -50px;
    pointer-events: none;
}

.cta-decor-circle-2 {
    position: absolute;
    width: 240px;
    height: 240px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(44, 93, 161, 0.1) 0%, rgba(255,255,255,0) 70%);
    bottom: -80px;
    left: -60px;
    pointer-events: none;
}

.cta-main-title {
    font-family: 'Playfair Display', Georgia, serif;
    line-height: 1.3;
}

/* The Animated Elite Call to Action Button */
.premium-animated-cta-btn {
    position: relative;
    background: linear-gradient(135deg, var(--color-accent-gold) 0%, var(--color-accent-gold-hover) 100%);
    color: var(--color-primary-deep) !important;
    border: 2px solid var(--color-accent-gold);
    box-shadow: 0 10px 25px rgba(255, 201, 60, 0.35), inset 0 1px 0 rgba(255,255,255,0.4);
    overflow: hidden;
    width: 100%;
}

.premium-animated-cta-btn:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 16px 32px rgba(255, 201, 60, 0.45);
    background: linear-gradient(135deg, var(--color-accent-gold-hover) 0%, var(--color-accent-gold) 100%);
}

.premium-animated-cta-btn:active {
    transform: translateY(-1px) scale(0.99);
    box-shadow: 0 6px 15px rgba(255, 201, 60, 0.3);
}

/* Linear Button Shine Animation Effect */
.btn-shine-effect {
    position: absolute;
    top: 0;
    left: -100%;
    width: 50%;
    height: 100%;
    background: linear-gradient(90deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.4) 50%, rgba(255,255,255,0) 100%);
    transform: skewX(-25deg);
    animation: buttonShineGlance 4.5s infinite ease-in-out;
}

.btn-text-content {
    position: relative;
    z-index: 5;
}

/* -------------------------------------------------------------
   10. PREMIUM AMAZON-STYLE REVIEWS SECTION ARCHITECTURE
   ------------------------------------------------------------- */
.premium-reviews-section {
    position: relative;
}

.reviews-section-main-title {
    color: var(--color-primary-deep);
}

/* Cards layout arranged strictly vertically */
.reviews-vertical-container {
    width: 100%;
}

.amazon-style-review-card {
    background-color: rgba(251, 253, 255, 0.7);
    border: 1px solid rgba(10, 25, 49, 0.05);
    box-shadow: var(--shadow-level-2);
    position: relative;
}

.amazon-style-review-card:hover {
    background-color: var(--color-neutral-pure-white);
    border-color: rgba(10, 25, 49, 0.1);
    box-shadow: var(--shadow-level-3);
}

/* Vertical left border accent dynamic trigger on card hover */
.review-hover-accent-line {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    width: 0;
    background-color: var(--color-primary-deep);
    transition: var(--fast-transition);
}

.amazon-style-review-card:hover .review-hover-accent-line {
    width: 4px;
}

/* Review Avatar Items */
.avatar-frame {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    padding: 2px;
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-accent-gold) 100%);
    box-shadow: var(--shadow-level-1);
}

.avatar-img-element {
    width: 100%;
    height: 100%;
    background-color: var(--color-neutral-pure-white);
}

.avatar-verified-dot {
    position: absolute;
    width: 11px;
    height: 11px;
    background-color: #10b981; /* Verified Success Green */
    border: 2px solid var(--color-neutral-pure-white);
    border-radius: 50%;
    bottom: 0;
    right: 0;
}

.review-username {
    color: var(--color-neutral-dark);
}

.review-subject-title {
    letter-spacing: -0.01em;
}

.purchase-verified-badge {
    background-color: rgba(255, 201, 60, 0.12);
    padding: 2px 8px;
    border-radius: 4px;
    display: inline-block;
}

/* Review Attached Evidence Photo Thumbnails */
.attached-photo-item {
    width: 65px;
    height: 65px;
    background-color: var(--color-neutral-gray-100);
}

.attached-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.attached-photo-item:hover .attached-img {
    transform: scale(1.12);
}

.attached-img-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: rgba(10, 25, 49, 0.15);
    opacity: 0;
    transition: var(--fast-transition);
    pointer-events: none;
}

.attached-photo-item:hover .attached-img-overlay {
    opacity: 1;
}

/* -------------------------------------------------------------
   11. FOOTER BLUE-METALLIC TECH PATTERN DESIGN
   ------------------------------------------------------------- */
.custom-premium-footer {
    background-color: var(--color-primary-deep);
    border-top: 3px solid var(--color-accent-gold);
}

.footer-brand-heading {
    letter-spacing: 0.15em;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.footer-nav-anchor {
    position: relative;
    font-size: 13px;
}

.footer-nav-anchor::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-accent-gold);
    transition: var(--fast-transition);
}

.footer-nav-anchor:hover::after {
    width: 100%;
}

/* -------------------------------------------------------------
   12. PURE CSS ADVANCED ANIMATIONS DECLARATIONS
   ------------------------------------------------------------- */
@keyframes pulseGlow {
    0% { transform: scale(1); box-shadow: 0 0 4px var(--color-accent-gold); opacity: 0.8; }
    50% { transform: scale(1.15); box-shadow: 0 0 12px var(--color-accent-gold); opacity: 1; }
    100% { transform: scale(1); box-shadow: 0 0 4px var(--color-accent-gold); opacity: 0.8; }
}

@keyframes buttonShineGlance {
    0% { left: -100%; }
    30% { left: 150%; }
    100% { left: 150%; }
}

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

/* -------------------------------------------------------------
   13. COMPREHENSIVE RESPONSIVE DESIGN MEDIA QUERIES (Mobile-First)
   ------------------------------------------------------------- */

/* Small Smartphones (320px up to 480px) */
@media (min-width: 320px) {
    .premium-image-viewframe {
        height: 270px;
    }
    .thumb-nav-item {
        height: 58px;
    }
    .main-product-heading {
        font-size: 24px;
    }
    .mega-cta-section {
        margin-top: 32px;
        margin-bottom: 32px;
    }
    .premium-animated-cta-btn {
        padding: 14px 20px;
        font-size: 13px;
    }
}

/* Standard Smartphones / Medium viewports (375px and above) */
@media (min-width: 375px) {
    .premium-image-viewframe {
        height: 310px;
    }
    .thumb-nav-item {
        height: 64px;
    }
    .main-product-heading {
        font-size: 26px;
    }
}

/* Phablets & Small Tablets (640px and above) */
@media (min-width: 640px) {
    .premium-image-viewframe {
        height: 400px;
    }
    .thumb-nav-item {
        height: 85px;
    }
    .main-product-heading {
        font-size: 30px;
    }
    .premium-animated-cta-btn {
        width: auto;
        min-width: 280px;
    }
}

/* Full Medium Tablets / iPads (768px and above) */
@media (min-width: 768px) {
    .premium-product-card {
        padding: 40px;
    }
    .premium-image-viewframe {
        height: 460px;
    }
    .thumb-nav-item {
        height: 100px;
    }
    .main-product-heading {
        font-size: 34px;
    }
}

/* Desktop Monitors & Large Viewports (1024px and above) */
@media (min-width: 1024px) {
    .premium-product-card {
        padding: 48px;
    }
    .premium-image-viewframe {
        height: 390px;
    }
    .thumb-nav-item {
        height: 72px;
    }
    .main-product-heading {
        font-size: 36px;
    }
}

/* Ultra-Wide Desktop Viewports (1280px and above) */
@media (min-width: 1280px) {
    .premium-image-viewframe {
        height: 440px;
    }
    .thumb-nav-item {
        height: 82px;
    }
}