:root {
    /* Primary Colors */
    --bitherm-blue: #0093D8;
    --bitherm-red: #EE0032;
    
    /* Neutral Colors */
    --white: #FFFFFF;
    --black: #000000;
    --gray-100: #F8F9FA;
    --gray-200: #E9ECEF;
    --gray-500: #6C757D;
    --gray-800: #343A40;
    
    /* Semantic Colors */
    --success: #28A745;
    --warning: #FFC107;
    --danger: #DC3545;
    
    /* Typography */
    --font-family: 'Formular', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-bold: 700;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-xxl: 48px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;

    /* Backgrounds */
    --bg-light: var(--gray-100);

    /* Text */
    --text-color: var(--gray-800);
    --text-gray: var(--gray-500);
}

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

body {
    font-family: var(--font-family);
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--bitherm-blue);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    background-color: var(--white);
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--gray-100);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header.scrolled {
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header__logo img {
    height: 40px; /* Adjust as needed */
}

.header__nav ul {
    list-style: none;
    display: flex;
    gap: var(--spacing-xl);
}

.header__nav a {
    color: var(--gray-800);
    font-weight: var(--font-weight-medium);
    transition: color 0.2s ease;
}

.header__nav a:hover, .header__nav a.active {
    color: var(--bitherm-blue);
    text-decoration: none;
}

.header__actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.lang-switcher button {
    background: none;
    border: none;
    color: var(--gray-500);
    cursor: pointer;
    font-weight: var(--font-weight-medium);
    padding: 0 var(--spacing-xs);
}

.lang-switcher button.active {
    color: var(--bitherm-blue);
}

.header__phone {
    font-weight: var(--font-weight-bold);
    color: var(--bitherm-blue);
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url('/img/hero-bg.jpg') no-repeat center center/cover; /* Placeholder background */
    color: var(--white);
    text-align: center;
    padding: var(--spacing-xxl) var(--spacing-md);
    min-height: 500px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-xl);
}

.hero__title {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.hero__subtitle {
    font-size: 1.2rem;
    max-width: 800px;
    margin-bottom: var(--spacing-xl);
}

.hero__cta .btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1.1rem;
    border-radius: var(--radius-md);
}

.hero__icons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.hero__icon-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.8rem;
    text-align: center;
    width: 90px;
}

.hero__icon-item img {
    width: 40px;
    height: 40px;
}

/* General Sections */
.section {
    padding: var(--spacing-xxl) 0;
}

.section.bg-light {
    background-color: var(--bg-light);
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: 1.1rem;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--text-gray);
}

/* Grid system */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xl);
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-xl);
}

/* Product/Category Cards */
.product-card, .category-card {
    background-color: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: inherit;
}

.product-card:hover, .category-card:hover {
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    transform: translateY(-5px);
    text-decoration: none;
}

.product-card__image, .category-card__image {
    width: 100%;
    height: 200px; /* Fixed height for images */
    overflow: hidden;
}

.product-card__image img, .category-card__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.product-card:hover .product-card__image img, .category-card:hover .category-card__image img {
    transform: scale(1.05);
}

.product-card__content, .category-card__content {
    padding: var(--spacing-md);
    flex-grow: 1;
}

.product-card__title, .category-card__title {
    font-size: 1.2rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-xs);
    color: var(--bitherm-blue);
}

.product-card__category, .product-card__sku, .category-card__count {
    font-size: 0.9rem;
    color: var(--gray-500);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    font-weight: var(--font-weight-medium);
    text-align: center;
    vertical-align: middle;
    cursor: pointer;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    transition: all 0.2s ease-in-out;
}

.btn-primary {
    color: var(--white);
    background-color: var(--bitherm-blue);
    border-color: var(--bitherm-blue);
}

.btn-primary:hover {
    background-color: darken(var(--bitherm-blue), 10%); /* Placeholder for CSS preprocessor func */
    border-color: darken(var(--bitherm-blue), 10%);
}

.btn-secondary {
    color: var(--gray-800);
    background-color: var(--gray-200);
    border-color: var(--gray-200);
}

.btn-secondary:hover {
    background-color: darken(var(--gray-200), 10%);
    border-color: darken(var(--gray-200), 10%);
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.1rem;
    border-radius: var(--radius-md);
}

/* Breadcrumbs */
.breadcrumbs {
    padding: var(--spacing-md) 0;
    font-size: 0.9rem;
    color: var(--gray-500);
}

.breadcrumbs a {
    color: var(--gray-500);
    text-decoration: none;
}

.breadcrumbs a:hover {
    text-decoration: underline;
}

.breadcrumbs span {
    color: var(--gray-800);
    font-weight: var(--font-weight-medium);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: var(--font-weight-medium);
}

.form-control {
    display: block;
    width: 100%;
    padding: var(--spacing-sm);
    font-size: 1rem;
    line-height: 1.5;
    color: var(--gray-800);
    background-color: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-sm);
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
    border-color: var(--bitherm-blue);
    outline: 0;
    box-shadow: 0 0 0 0.25rem rgba(0, 147, 216, 0.25);
}

textarea.form-control {
    min-height: 80px;
    resize: vertical;
}

/* Alerts */
.alert {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
}

.alert-success {
    color: #0f5132;
    background-color: #d1e7dd;
    border-color: #badbcc;
}

.alert-danger {
    color: #842029;
    background-color: #f8d7da;
    border-color: #f5c2c7;
}

/* Product Detail Page */
.product-main {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xxl);
    padding: var(--spacing-xxl) 0;
}

.product-gallery {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.product-gallery__main-image {
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.product-gallery__main-image img {
    width: 100%;
    height: auto;
    display: block;
}

.product-gallery__thumbnails {
    display: flex;
    gap: var(--spacing-sm);
    overflow-x: auto;
    padding-bottom: var(--spacing-xs);
}

.product-gallery__thumbnails img {
    width: 80px;
    height: 80px;
    object-fit: cover;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: border-color 0.2s ease;
}

.product-gallery__thumbnails img:hover {
    border-color: var(--bitherm-blue);
}

.product-details {
    /* Styles for product information */
}

.product-title {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.product-sku {
    font-size: 1.1rem;
    color: var(--gray-500);
    margin-bottom: var(--spacing-xl);
}

.product-description {
    margin-bottom: var(--spacing-xl);
}

.product-specs ul {
    list-style: none;
    padding: 0;
    margin-bottom: var(--spacing-xl);
}

.product-specs li {
    margin-bottom: var(--spacing-xs);
}

.product-features .features-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.feature-item img {
    width: 30px;
    height: 30px;
}

/* Footer */
.footer {
    background-color: var(--gray-800);
    color: var(--white);
    padding: var(--spacing-xxl) 0 var(--spacing-md) 0;
    font-size: 0.9rem;
}

.footer__main {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xxl);
    margin-bottom: var(--spacing-xxl);
}

.footer__logo {
    height: 50px;
    margin-bottom: var(--spacing-md);
}

.footer__about p {
    color: var(--gray-200);
    margin-bottom: var(--spacing-md);
}

.footer__social a {
    color: var(--white);
    margin-right: var(--spacing-md);
    transition: color 0.2s ease;
}

.footer__social a:hover {
    color: var(--bitherm-blue);
}

.footer__title {
    font-size: 1.1rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--white);
}

.footer__links ul {
    list-style: none;
}

.footer__links a {
    color: var(--gray-200);
    display: block;
    margin-bottom: var(--spacing-sm);
}

.footer__links a:hover {
    color: var(--bitherm-blue);
    text-decoration: none;
}

.footer__contact p {
    color: var(--gray-200);
    margin-bottom: var(--spacing-sm);
}

.footer__contact a {
    color: var(--gray-200);
}

.footer__contact a:hover {
    color: var(--bitherm-blue);
}

.footer__bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--gray-500);
    color: var(--gray-200);
}

/* Utility classes */
.text-center {
    text-align: center;
}
.text-muted {
    color: var(--gray-500);
}
.mb-4 {
    margin-bottom: var(--spacing-xl);
}
.mt-4 {
    margin-top: var(--spacing-xl);
}
.py-4 {
    padding-top: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
}
.d-flex {
    display: flex;
}
.justify-content-end {
    justify-content: flex-end;
}
.mb-3 {
    margin-bottom: var(--spacing-md);
}
.bg-success {
    background-color: var(--success);
    color: var(--white);
}
.bg-danger {
    background-color: var(--danger);
    color: var(--white);
}
.badge {
    padding: 0.35em 0.65em;
    border-radius: var(--radius-sm);
    font-size: 0.75em;
    font-weight: var(--font-weight-bold);
}
.table {
    width: 100%;
    margin-bottom: 1rem;
    color: var(--text-color);
    vertical-align: top;
    border-color: var(--gray-200);
}
.table > :not(caption) > * > * {
    padding: 0.5rem 0.5rem;
    background-color: var(--white);
    border-bottom-width: 1px;
    box-shadow: inset 0 0 0 9999px var(--white);
}
.table > thead {
    vertical-align: bottom;
}
.table > :not(caption) > * > * {
    border-bottom-width: 1px;
}
.table-bordered {
    border: 1px solid var(--gray-200);
}
.table-bordered > :not(caption) > * {
    border-width: 0 1px;
}
.table-hover > tbody > tr:hover {
    color: var(--text-color);
    background-color: rgba(0, 0, 0, 0.075);
}
.btn-sm {
    padding: 0.25rem 0.5rem;
    font-size: 0.875rem;
    border-radius: var(--radius-sm);
}
.btn-info {
    color: var(--white);
    background-color: var(--bitherm-blue);
    border-color: var(--bitherm-blue);
}
.btn-info:hover {
    background-color: darken(var(--bitherm-blue), 10%);
    border-color: darken(var(--bitherm-blue), 10%);
}
.d-inline {
    display: inline-block !important;
}
.col-md-6 {
    flex: 0 0 auto;
    width: 50%;
}
.row {
    --bs-gutter-x: 1.5rem;
    --bs-gutter-y: 0;
    display: flex;
    flex-wrap: wrap;
    margin-top: calc(-1 * var(--bs-gutter-y));
    margin-right: calc(-.5 * var(--bs-gutter-x));
    margin-left: calc(-.5 * var(--bs-gutter-x));
}
.row > * {
    flex-shrink: 0;
    width: 100%;
    max-width: 100%;
    padding-right: calc(var(--bs-gutter-x) * .5);
    padding-left: calc(var(--bs-gutter-x) * .5);
    margin-top: var(--bs-gutter-y);
}
.card {
    position: relative;
    display: flex;
    flex-direction: column;
    min-width: 0;
    word-wrap: break-word;
    background-color: #fff;
    background-clip: border-box;
    border: 1px solid rgba(0,0,0,.125);
    border-radius: .25rem;
}
.shadow-sm {
    box-shadow: 0 .125rem .25rem rgba(0,0,0,.075)!important;
}
.card-body {
    flex: 1 1 auto;
    padding: 1rem 1rem;
}
.card-title {
    margin-bottom: .5rem;
    font-weight: var(--font-weight-medium);
}
.card-text {
    margin-bottom: 1rem;
}
.btn-primary {
    color: var(--white);
    background-color: var(--bitherm-blue);
    border-color: var(--bitherm-blue);
}
.alert {
    position: relative;
    padding: 1rem 1rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
    border-radius: .25rem;
}
.alert-dismissible .btn-close {
    position: absolute;
    top: 0;
    right: 0;
    z-index: 2;
    padding: 1rem 1rem;
}
.fade {
    transition: opacity .15s linear;
}
.show {
    opacity: 1;
}
.btn-close {
    box-sizing: content-box;
    width: 1em;
    height: 1em;
    padding: .25em .25em;
    color: #000;
    background: transparent url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='%23000'%3e%3cpath d='M.293.293a1 1 0 011.414 0L8 6.586 14.293.293a1 1 0 111.414 1.414L9.414 8l6.293 6.293a1 1 0 01-1.414 1.414L8 9.414l-6.293 6.293a1 1 0 01-1.414-1.414L6.586 8 .293 1.707a1 1 0 010-1.414z'/%3e%3c/svg%3e") center/1em auto no-repeat;
    border: 0;
    border-radius: .25rem;
    opacity: .5;
}
.btn-close:hover {
    color: #000;
    text-decoration: none;
    opacity: .75;
}
.form-check {
    display: block;
    min-height: 1.5rem;
    padding-left: 1.5em;
    margin-bottom: .125rem;
}
.form-check .form-check-input {
    float: left;
    margin-left: -1.5em;
}
.form-check-input {
    width: 1em;
    height: 1em;
    margin-top: .25em;
    vertical-align: top;
    background-color: #fff;
    background-repeat: no-repeat;
    background-position: center;
    background-size: contain;
    border: 1px solid rgba(0,0,0,.25);
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    print-color-adjust: exact;
}
.form-check-input[type=checkbox] {
    border-radius: .25em;
}
.form-check-input:checked {
    background-color: #0d6efd;
    border-color: #0d6efd;
}
.form-check-input[type=checkbox]:checked {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3e%3cpath fill='%23fff' d='M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z'/%3e%3c/svg%3e");
}
.form-check-label {
    margin-bottom: 0;
}