/* 
** Air Filters Website CSS
** Color Palette:
** - Primary Background: #F4F4F4 (light concrete)
** - Accent: #00C7B1 (turquoise-green)
** - Contrast: #1E1E2F (deep graphite)
** - Highlight: #FFE04B (sunny yellow)
** - Fonts: "Poppins", "Open Sans"
*/

/* === Reset and Base Styles === */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-bg: #F4F4F4;
    --color-accent: #00C7B1;
    --color-contrast: #1E1E2F;
    --color-highlight: #FFE04B;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-white: #FFFFFF;
    --color-light-gray: #E0E0E0;
    --color-medium-gray: #999999;
    --color-dark-gray: #555555;
    
    --font-primary: 'Poppins', sans-serif;
    --font-secondary: 'Open Sans', sans-serif;
    
    --transition-fast: 0.3s ease;
    --transition-medium: 0.5s ease;
    --transition-slow: 0.8s ease;
    
    --shadow-small: 0 2px 5px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 5px 15px rgba(0, 0, 0, 0.1);
    --shadow-large: 0 10px 25px rgba(0, 0, 0, 0.1);
    
    --border-radius-small: 4px;
    --border-radius-medium: 8px;
    --border-radius-large: 12px;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
}

html {
    font-size: 62.5%; /* 10px for easier rem calculation */
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 1.6rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
}

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

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: all var(--transition-fast);
}

a:hover, a:focus {
    color: var(--color-contrast);
}

ul {
    list-style: none;
}

.container {
    width: 100%;
    max-width: 120rem;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: var(--spacing-lg) 0;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-primary);
    color: var(--color-contrast);
    margin-bottom: var(--spacing-md);
    line-height: 1.3;
}

h1 {
    font-size: 4.2rem;
    font-weight: 700;
}

h2 {
    font-size: 3.2rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    position: relative;
}

h2::after {
    content: '';
    display: block;
    width: 6rem;
    height: 0.4rem;
    background-color: var(--color-accent);
    margin: 1.5rem auto 0;
    border-radius: 2px;
}

h3 {
    font-size: 2.4rem;
    font-weight: 500;
}

p {
    margin-bottom: var(--spacing-sm);
}

.icon {
    width: 2.4rem;
    height: 2.4rem;
    fill: var(--color-accent);
}

/* === Buttons === */
.btn {
    display: inline-block;
    padding: 1.2rem 2.4rem;
    border-radius: var(--border-radius-medium);
    font-family: var(--font-primary);
    font-size: 1.6rem;
    font-weight: 500;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    box-shadow: var(--shadow-small);
}

.btn-primary {
    background-color: var(--color-accent);
    color: var(--color-white);
}

.btn-primary:hover, .btn-primary:focus {
    background-color: var(--color-contrast);
    color: var(--color-white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.btn-secondary {
    background-color: var(--color-highlight);
    color: var(--color-contrast);
}

.btn-secondary:hover, .btn-secondary:focus {
    background-color: var(--color-contrast);
    color: var(--color-white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.btn-primary-small {
    padding: 0.8rem 1.6rem;
    font-size: 1.4rem;
    background-color: var(--color-accent);
    color: var(--color-white);
}

.btn-primary-small:hover, .btn-primary-small:focus {
    background-color: var(--color-contrast);
    color: var(--color-white);
}

/* === Header === */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--color-white);
    z-index: 1000;
    box-shadow: var(--shadow-small);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
}

.logo img {
    height: 5rem;
}

.nav-toggle {
    display: none;
}

.nav-toggle-label {
    display: none;
}

.main-nav .nav-list {
    display: flex;
    gap: 2rem;
}

.main-nav a {
    color: var(--color-contrast);
    font-weight: 500;
    padding: 0.5rem 1rem;
    position: relative;
}

.main-nav a:not(.btn)::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--color-accent);
    transform: scaleX(0);
    transform-origin: center;
    transition: transform var(--transition-fast);
}

.main-nav a:not(.btn):hover::after,
.main-nav a:not(.btn):focus::after {
    transform: scaleX(1);
}

/* === Main Content Offset === */
.site-main {
    margin-top: 8rem;
}

/* === Hero Section === */
.hero {
    background-color: var(--color-white);
    padding: var(--spacing-xl) 0;
}

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

.hero-content {
    flex: 1;
}

.hero-content h1 {
    margin-bottom: var(--spacing-sm);
    animation: fadeInUp 1s ease-out;
}

.hero-content p {
    font-size: 1.8rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text-light);
    animation: fadeInUp 1s ease-out 0.3s;
    animation-fill-mode: both;
}

.hero-content .btn {
    animation: fadeInUp 1s ease-out 0.6s;
    animation-fill-mode: both;
}

.hero-image {
    flex: 1;
    animation: fadeIn 1.5s ease-out;
}

.hero-image img {
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-large);
}

/* === About Section === */
.about {
    background-color: var(--color-bg);
}

.tagline {
    font-size: 2rem;
    color: var(--color-accent);
    font-style: italic;
    text-align: center;
    margin-bottom: var(--spacing-md);
}

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

.about-text {
    flex: 1;
}

.about-image {
    flex: 1;
}

.about-image img {
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-medium);
}

/* === Benefits Section === */
.benefits {
    background-color: var(--color-white);
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(25rem, 1fr));
    gap: var(--spacing-md);
}

.benefit-card {
    background-color: var(--color-bg);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-medium);
    box-shadow: var(--shadow-small);
    text-align: center;
    transition: transform var(--transition-medium);
}

.benefit-card:hover {
    transform: translateY(-1rem);
    box-shadow: var(--shadow-medium);
}

.benefit-icon {
    margin: 0 auto var(--spacing-sm);
    width: 6rem;
    height: 6rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-white);
    border-radius: 50%;
    box-shadow: var(--shadow-small);
}

.benefit-icon .icon {
    width: 3.2rem;
    height: 3.2rem;
}

.benefit-card h3 {
    margin-bottom: var(--spacing-sm);
}

/* === Products Section === */
.products {
    background-color: var(--color-bg);
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(30rem, 1fr));
    gap: var(--spacing-lg);
}

.product-card {
    background-color: var(--color-white);
    border-radius: var(--border-radius-medium);
    overflow: hidden;
    box-shadow: var(--shadow-medium);
    transition: transform var(--transition-medium);
}

.product-card:hover {
    transform: translateY(-1rem);
    box-shadow: var(--shadow-large);
}

.product-image img {
    width: 100%;
    height: 25rem;
    object-fit: cover;
}

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

.product-features {
    margin: var(--spacing-sm) 0;
    padding-left: var(--spacing-sm);
}

.product-features li {
    margin-bottom: 0.5rem;
    position: relative;
    padding-left: 2rem;
}

.product-features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-weight: bold;
}

/* === Contact Section === */
.contact {
    background-color: var(--color-white);
}

.contact-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(30rem, 1fr));
    gap: var(--spacing-lg);
}

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

.contact-details {
    margin-top: var(--spacing-md);
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.contact-item .icon {
    margin-right: var(--spacing-sm);
    min-width: 2.4rem;
}

.contact-form {
    background-color: var(--color-bg);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-medium);
    box-shadow: var(--shadow-medium);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 1.2rem;
    border: 1px solid var(--color-light-gray);
    border-radius: var(--border-radius-small);
    font-family: var(--font-primary);
    font-size: 1.6rem;
    transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group select:focus {
    border-color: var(--color-accent);
    outline: none;
}

.form-group.checkbox {
    display: flex;
    align-items: flex-start;
}

.form-group.checkbox input {
    width: auto;
    margin-right: var(--spacing-xs);
    margin-top: 0.5rem;
}

.form-group.checkbox label {
    font-weight: normal;
    flex: 1;
}

/* === Testimonials Section === */
.testimonials {
    background-color: var(--color-bg);
}

.testimonials-slider {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
}

.testimonial {
    background-color: var(--color-white);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-medium);
    box-shadow: var(--shadow-small);
    flex: 1;
    min-width: 30rem;
    max-width: 40rem;
    display: flex;
    flex-direction: column;
}

.testimonial-content {
    flex: 1;
    position: relative;
    padding-top: 2rem;
}

.testimonial-content::before {
    content: '"';
    position: absolute;
    top: -1rem;
    left: -1rem;
    font-size: 6rem;
    color: var(--color-light-gray);
    font-family: sans-serif;
    line-height: 1;
}

.testimonial-author {
    margin-top: var(--spacing-sm);
    text-align: right;
    font-style: italic;
    color: var(--color-text-light);
}

/* === FAQ Section === */
.faq {
    background-color: var(--color-white);
}

.faq-container {
    max-width: 80rem;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: var(--spacing-sm);
    border: 1px solid var(--color-light-gray);
    border-radius: var(--border-radius-medium);
    overflow: hidden;
}

.faq-item input {
    display: none;
}

.faq-question {
    display: block;
    padding: var(--spacing-md);
    cursor: pointer;
    font-weight: 500;
    position: relative;
    transition: background-color var(--transition-fast);
}

.faq-question::after {
    content: '+';
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 2rem;
    color: var(--color-accent);
    transition: transform var(--transition-fast);
}

.faq-answer {
    padding: 0 var(--spacing-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-medium), padding var(--transition-medium);
}

.faq-item input:checked ~ .faq-answer {
    max-height: 50rem;
    padding: 0 var(--spacing-md) var(--spacing-md);
}

.faq-item input:checked ~ .faq-question {
    background-color: var(--color-bg);
}

.faq-item input:checked ~ .faq-question::after {
    transform: translateY(-50%) rotate(45deg);
}

/* === Cookie Popup === */
.cookie-popup {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    padding: var(--spacing-md);
    box-shadow: 0 -5px 15px rgba(0, 0, 0, 0.1);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.cookie-popup p {
    margin: 0;
    flex: 1;
    min-width: 30rem;
}

.cookie-popup .cookie-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

/* === Footer === */
.site-footer {
    background-color: var(--color-contrast);
    color: var(--color-white);
    padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-content {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-logo {
    flex: 1;
    min-width: 25rem;
}

.footer-logo img {
    height: 5rem;
    margin-bottom: var(--spacing-sm);
}

.footer-logo .tagline {
    font-size: 1.6rem;
    text-align: left;
    color: var(--color-medium-gray);
}

.footer-links {
    flex: 2;
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer-nav, .footer-legal, .footer-contact {
    flex: 1;
    min-width: 20rem;
}

.footer-links h3 {
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
    font-size: 1.8rem;
}

.footer-links ul li {
    margin-bottom: var(--spacing-xs);
}

.footer-links a {
    color: var(--color-medium-gray);
}

.footer-links a:hover, .footer-links a:focus {
    color: var(--color-accent);
}

.footer-contact ul li {
    display: flex;
    align-items: center;
    color: var(--color-medium-gray);
}

.footer-contact .icon {
    fill: var(--color-medium-gray);
    margin-right: var(--spacing-xs);
    min-width: 2rem;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--color-medium-gray);
    font-size: 1.4rem;
}

/* === Animations === */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(2rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* === Media Queries === */
@media (max-width: 1200px) {
    html {
        font-size: 60%;
    }
}

@media (max-width: 992px) {
    html {
        font-size: 58%;
    }
    
    .hero .container {
        flex-direction: column;
    }
    
    .about-content {
        flex-direction: column;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 56%;
    }
    
    .nav-toggle-label {
        display: block;
        position: relative;
        z-index: 2;
        cursor: pointer;
    }
    
    .nav-toggle-label span,
    .nav-toggle-label span::before,
    .nav-toggle-label span::after {
        display: block;
        width: 2.5rem;
        height: 0.3rem;
        background-color: var(--color-contrast);
        position: relative;
        transition: all var(--transition-fast);
    }
    
    .nav-toggle-label span::before,
    .nav-toggle-label span::after {
        content: '';
        position: absolute;
    }
    
    .nav-toggle-label span::before {
        top: -0.8rem;
    }
    
    .nav-toggle-label span::after {
        bottom: -0.8rem;
    }
    
    .main-nav {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--color-white);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: transform var(--transition-medium), opacity var(--transition-medium), visibility var(--transition-medium);
        box-shadow: var(--shadow-medium);
    }
    
    .nav-toggle:checked ~ .main-nav {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span {
        background-color: transparent;
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span::before {
        top: 0;
        transform: rotate(45deg);
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span::after {
        bottom: 0;
        transform: rotate(-45deg);
    }
    
    .main-nav .nav-list {
        flex-direction: column;
        padding: var(--spacing-sm);
    }
    
    .main-nav .nav-list li {
        width: 100%;
        text-align: center;
    }
    
    .main-nav .nav-list a {
        display: block;
        padding: var(--spacing-sm);
    }
}

@media (max-width: 576px) {
    html {
        font-size: 54%;
    }
    
    section {
        padding: var(--spacing-md) 0;
    }
    
    h1 {
        font-size: 3.6rem;
    }
    
    h2 {
        font-size: 2.8rem;
    }
    
    .cookie-popup {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .cookie-popup p {
        margin-bottom: var(--spacing-sm);
    }
}

/* === Legal Pages Styles === */
.legal-page {
    padding: var(--spacing-lg) 0;
}

.legal-page h1 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.legal-content {
    max-width: 80rem;
    margin: 0 auto;
}

.legal-content h2 {
    font-size: 2.2rem;
    text-align: left;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.legal-content h2::after {
    display: none;
}

.legal-content h3 {
    font-size: 1.8rem;
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.legal-content p, .legal-content ul {
    margin-bottom: var(--spacing-md);
}

.legal-content ul {
    padding-left: 2rem;
    list-style-type: disc;
}

.legal-content ul li {
    margin-bottom: var(--spacing-xs);
}

.legal-date {
    margin-top: var(--spacing-lg);
    font-style: italic;
    color: var(--color-text-light);
}