:root {
    --primary-color: #A0B9C0; /* Soft, luxurious grey-blue */
    --secondary-color: #E2E8F0; /* Light grey */
    --accent-color: #374151; /* Darker accent for text */
    --text-color-light: #F8FAFC; /* Off-white for light text */
    --text-color-dark: #1F2937; /* Dark grey for general text */
    --bg-light: #F8FAFC;
    --bg-dark: #1A202C; /* Deep charcoal for premium feel */

    --font-heading: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    --font-body: 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', sans-serif;

    --max-width: 1200px;
    --spacing-unit: 1.5rem; /* 24px */
}

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

html {
    scroll-behavior: smooth;
}

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

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

.section-spacing {
    padding: calc(var(--spacing-unit) * 4) 0; /* 96px top/bottom */
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--accent-color);
    margin-bottom: var(--spacing-unit);
    line-height: 1.2;
}

h1 { font-size: 3.5rem; } /* 56px */
h2 { font-size: 2.8rem; } /* 45px */
h3 { font-size: 2.2rem; } /* 35px */
h4 { font-size: 1.8rem; } /* 29px */
p {
    margin-bottom: var(--spacing-unit);
    font-size: 1.1rem; /* 18px */
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}
a:hover {
    color: var(--accent-color);
}

ul {
    list-style: none;
}

/* Header */
.header {
    background-color: var(--bg-dark);
    color: var(--text-color-light);
    padding: var(--spacing-unit) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap; /* Allow wrapping on small screens */
}

.logo {
    font-size: 1.8rem;
    color: var(--text-color-light);
    font-weight: 700;
}

.nav ul {
    display: flex;
    gap: var(--spacing-unit);
}

.nav a {
    color: var(--text-color-light);
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

.nav a:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--accent-color) 100%);
    color: var(--text-color-light);
    padding: calc(var(--spacing-unit) * 6) 0; /* 144px top/bottom */
    text-align: center;
}

.hero .container {
    display: flex;
    flex-direction: row; /* Default for desktop */
    align-items: center;
    gap: calc(var(--spacing-unit) * 2);
}

.hero-content {
    flex: 1;
    text-align: left;
}

.hero h2 {
    font-size: 4rem; /* 64px */
    color: var(--text-color-light);
    margin-bottom: var(--spacing-unit);
}

.hero p {
    font-size: 1.4rem; /* 22px */
    color: var(--secondary-color);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-visual .product-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.cta-button {
    display: inline-block;
    background-color: var(--primary-color);
    color: var(--bg-dark);
    padding: 1rem 2.5rem;
    border-radius: 5px;
    font-size: 1.2rem;
    font-weight: 600;
    text-transform: uppercase;
    transition: background-color 0.3s ease, transform 0.2s ease;
    border: none;
    cursor: pointer;
}

.cta-button:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
}

.secondary-cta {
    background-color: var(--accent-color);
    color: var(--text-color-light);
}

.secondary-cta:hover {
    background-color: var(--primary-color);
    color: var(--bg-dark);
}

/* Pre-order Form (Hero and Contact) */
.preorder-form {
    background-color: rgba(255, 255, 255, 0.1);
    padding: calc(var(--spacing-unit) * 1.5);
    border-radius: 8px;
    margin-top: calc(var(--spacing-unit) * 2);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    max-width: 450px;
    margin-left: 0;
}

.preorder-form h3 {
    color: var(--text-color-light);
    margin-bottom: var(--spacing-unit);
    font-size: 1.5rem;
}

.preorder-form input[type="text"],
.preorder-form input[type="email"],
.preorder-form input[type="tel"],
.preorder-form textarea {
    width: 100%;
    padding: 0.8rem 1rem;
    margin-bottom: var(--spacing-unit);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 4px;
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-color-light);
    font-family: var(--font-body);
    font-size: 1rem;
}

.preorder-form input::placeholder,
.preorder-form textarea::placeholder {
    color: rgba(255, 255, 255, 0.6);
}

.preorder-form input:focus,
.preorder-form textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(var(--primary-color), 0.5);
}

.preorder-form textarea {
    resize: vertical;
    min-height: 100px;
}

/* Problem Solution Section */
.problem-solution {
    background-color: var(--bg-light);
    text-align: center;
}

.problem-solution .content-block {
    max-width: 800px;
    margin: 0 auto calc(var(--spacing-unit) * 3);
}
.problem-solution .content-block:last-child {
    margin-bottom: 0;
}

.problem-solution h3 {
    font-size: 2.5rem;
    color: var(--primary-color);
}

/* Features Section */
.features {
    background-color: var(--secondary-color);
    text-align: center;
}

.features h2 {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.feature-item {
    background-color: var(--bg-light);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.feature-item img {
    max-width: 100%;
    height: 200px; /* Consistent height for placeholders */
    object-fit: cover;
    margin-bottom: var(--spacing-unit);
    border-radius: 4px;
    background-color: #ccc; /* Placeholder background */
}

.feature-item h4 {
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.feature-item p {
    font-size: 1rem;
    margin-bottom: 0;
}

/* How It Works Section */
.how-it-works {
    background-color: var(--bg-light);
    text-align: center;
}

.how-it-works h2 {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.step-item {
    padding: calc(var(--spacing-unit) * 1.5);
    background-color: var(--secondary-color);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.step-item img {
    max-width: 100%;
    height: 180px; /* Consistent height */
    object-fit: cover;
    margin-bottom: var(--spacing-unit);
    border-radius: 4px;
    background-color: #ddd; /* Placeholder background */
}

.step-item h4 {
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}
.step-item p {
    font-size: 1rem;
    margin-bottom: 0;
}

/* Credibility Section */
.credibility {
    background-color: var(--primary-color);
    color: var(--bg-dark);
    text-align: center;
    padding: calc(var(--spacing-unit) * 4) 0;
}

.credibility h2 {
    color: var(--bg-dark);
    font-size: 2.5rem;
}
.credibility p {
    font-size: 1.2rem;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--accent-color);
}

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

.faq h2 {
    text-align: center;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.accordion-item {
    background-color: var(--secondary-color);
    margin-bottom: 1rem;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.accordion-header {
    width: 100%;
    padding: 1.2rem var(--spacing-unit);
    text-align: left;
    border: none;
    background-color: var(--secondary-color);
    font-family: var(--font-heading);
    font-size: 1.2rem;
    color: var(--accent-color);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.3s ease;
}

.accordion-header:hover {
    background-color: #DDE4EC;
}

.accordion-header::after {
    content: '+';
    font-size: 1.5rem;
    transition: transform 0.3s ease;
}

.accordion-header.active::after {
    content: '-';
    transform: rotate(180deg);
}

.accordion-content {
    padding: 0 var(--spacing-unit);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease-out, padding 0.5s ease-out;
    background-color: #F0F4F8;
    color: var(--text-color-dark);
}

.accordion-content p {
    padding: var(--spacing-unit) 0;
    margin-bottom: 0;
    border-top: 1px solid #E2E8F0;
}

.accordion-content.open {
    max-height: 300px; /* Adjust based on expected content height */
    padding-bottom: var(--spacing-unit);
}


/* About Us Section */
.about-us {
    background-color: var(--accent-color);
    color: var(--text-color-light);
    text-align: center;
}

.about-us h2 {
    color: var(--primary-color);
    margin-bottom: calc(var(--spacing-unit) * 1.5);
}

.about-us p {
    font-size: 1.15rem;
    line-height: 1.8;
    max-width: 800px;
    margin: 0 auto;
    color: var(--secondary-color);
}

/* Contact Section */
.contact {
    background-color: var(--bg-light);
    text-align: center;
}

.contact h2 {
    margin-bottom: var(--spacing-unit);
}

.contact p {
    font-size: 1.2rem;
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.contact .preorder-form {
    background-color: var(--secondary-color);
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    max-width: 500px;
    margin: 0 auto;
    padding: calc(var(--spacing-unit) * 2);
}

.contact .preorder-form h3 {
    color: var(--accent-color);
    margin-bottom: var(--spacing-unit);
    font-size: 1.8rem;
}

.contact .preorder-form input[type="text"],
.contact .preorder-form input[type="email"],
.contact .preorder-form input[type="tel"],
.contact .preorder-form textarea {
    background-color: var(--bg-light);
    border: 1px solid #CBD5E0;
    color: var(--text-color-dark);
}

.contact .preorder-form input::placeholder,
.contact .preorder-form textarea::placeholder {
    color: #A0AEC0;
}

/* Footer */
.footer {
    background-color: var(--bg-dark);
    color: var(--secondary-color);
    text-align: center;
    padding: var(--spacing-unit) 0;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
    h1 { font-size: 3rem; }
    h2 { font-size: 2.4rem; }
    h3 { font-size: 2rem; }
    .hero h2 { font-size: 3.5rem; }
    .hero p { font-size: 1.2rem; }
    .hero .container {
        flex-direction: column;
        text-align: center;
    }
    .hero-content, .hero-visual {
        text-align: center;
    }
    .preorder-form {
        margin-left: auto;
        margin-right: auto;
    }
}

@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-unit);
    }
    .nav ul {
        flex-direction: column;
        gap: 0.5rem;
    }
    .nav a {
        padding: 0.3rem 0;
    }
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.8rem; }
    .hero { padding: calc(var(--spacing-unit) * 4) 0; }
    .hero h2 { font-size: 2.8rem; }
    .hero p { font-size: 1.1rem; }
    .cta-button {
        padding: 0.8rem 2rem;
        font-size: 1.1rem;
    }
    .feature-grid, .steps-grid {
        grid-template-columns: 1fr;
    }
    .accordion-header {
        font-size: 1.1rem;
        padding: 1rem var(--spacing-unit);
    }
    .accordion-header::after {
        font-size: 1.2rem;
    }
}

@media (max-width: 480px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.8rem; }
    h3 { font-size: 1.5rem; }
    p { font-size: 1rem; }
    .hero h2 { font-size: 2.2rem; }
    .hero p { font-size: 1rem; }
    .preorder-form {
        padding: var(--spacing-unit);
    }
}