:root {
    /* Semi Design Blue Palette */
    --color-primary: #0064FA;
    /* Blue 5 */
    --color-primary-hover: #0062D6;
    /* Blue 6 */
    --color-primary-active: #004FB3;
    /* Blue 7 */

    --color-text-on-primary: #ffffff;
    /* Always white on primary buttons */

    /* Semi Design Neutral/Dark Palette */
    --color-bg-body: #16161A;
    /* Semi Dark Bg 0 */
    --color-bg-card: #232429;
    /* Semi Dark Bg 1 */
    --color-bg-surface: #35363C;
    /* Semi Dark Bg 2 */

    --color-text-main: #F9F9F9;
    /* Semi White/Text */
    --color-text-muted: #8F959E;
    /* Semi Grey 5 roughly */
    --color-white: #ffffff;
    --color-border: #43444A;
    /* Semi Dark Border (Bg 3 roughly) */

    /* Brand Updates */
    --color-bg-header: #F4F7FB;
    /* Option 1 Header Background */
    --color-border-bottom: #E5E7EB;
    /* Option 1 Border Bottom */
    --color-bg-sidebar: #1F2933;
    /* Dark Sidebar */

    --header-height-desktop: 64px;
    --header-height-mobile: 56px;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --container-width: 1200px;

    /* Semi Spacing (4px grid base) */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 32px;
    --spacing-xl: 64px;

    /* Semi Border Radius */
    --radius-sm: 3px;
    --radius-md: 6px;
    --radius-lg: 12px;

    /* Semi Shadows */
    --shadow-low: 0 0 1px rgba(0, 0, 0, 0.3), 0 2px 4px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 0 1px rgba(0, 0, 0, 0.3), 0 4px 14px rgba(0, 0, 0, 0.1);
}

[data-theme="light"] {
    --color-bg-body: #FFFFFF;
    /* Semi Light Bg 0 */
    --color-bg-card: #FFFFFF;
    /* Semi Light Bg 1 */
    --color-bg-surface: #F4F5F7;
    /* Slight contrast for surface */

    --color-text-main: #1C1F23;
    /* Semi Light Text */
    --color-text-muted: #6B7075;
    /* Semi Light Text Secondary */
    --color-white: #1C1F23;
    /* Inverting for headers in light mode */
    --color-border: #E1E3E6;
    /* Semi Light Border */
}

/* Theme Toggle Button */
.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text-muted);
    padding: 0.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    color: var(--color-white);
    background-color: rgba(148, 163, 184, 0.1);
}

[data-theme="light"] .theme-toggle:hover {
    background-color: rgba(15, 23, 42, 0.05);
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="light"] .sun-icon {
    display: block;
}

[data-theme="light"] .moon-icon {
    display: none;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--color-bg-body);
    color: var(--color-text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

ul {
    list-style: none;
}

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

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

/* Typography */
h1,
h2,
h3 {
    line-height: 1.2;
    font-weight: 700;
    color: var(--color-white);
}

h1 {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

h2 {
    font-size: 2.25rem;
    margin-bottom: var(--spacing-sm);
}

h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
}

p {
    color: var(--color-text-muted);
}

.highlight {
    color: var(--color-primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-text-on-primary);
}

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-1px);
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-secondary {
    background-color: transparent;
    border-color: var(--color-text-muted);
    color: var(--color-white);
}

.btn-secondary:hover {
    border-color: var(--color-white);
    background-color: rgba(255, 255, 255, 0.05);
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--color-bg-header);
    /* Option 1 Header Background */
    border-bottom: 1px solid var(--color-border-bottom);
    /* Option 1 Border Bottom */
    z-index: 1000;
    padding: 0;
    height: var(--header-height-desktop);
    display: flex;
    align-items: center;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    padding-left: 24px;
    /* Brand guideline: >= 24px */
}

.logo img {
    height: 42px;
    width: auto;
}

.nav {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    color: var(--color-text-muted);
    font-weight: 500;
}

.nav-link:hover {
    color: var(--color-white);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 6px;
}

.mobile-menu-btn span {
    display: block;
    width: 25px;
    height: 2px;
    background-color: var(--color-white);
}

/* Hero Section */
.hero {
    padding: 10rem 0 6rem;
    background: radial-gradient(circle at top right, rgba(59, 130, 246, 0.1), transparent 50%);
    text-align: center;
}

.hero-sub {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Trust Section */
.trust {
    padding: var(--spacing-lg) 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    background-color: var(--color-bg-card);
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
}

.trust-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2rem;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--color-text-main);
    font-weight: 500;
}

.icon-check {
    width: 20px;
    height: 20px;
    background-color: rgba(59, 130, 246, 0.2);
    border-radius: 50%;
    position: relative;
    flex-shrink: 0;
}

.icon-check::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -60%) rotate(45deg);
    width: 5px;
    height: 9px;
    border-right: 2px solid var(--color-primary);
    border-bottom: 2px solid var(--color-primary);
}

/* Features Section */
.features {
    padding: var(--spacing-xl) 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background-color: var(--color-bg-card);
    /* Updated to use variable */
    border: 1px solid var(--color-border);
    padding: 2rem;
    border-radius: var(--radius-lg);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
}

.feature-card ul {
    list-style: none;
    margin-top: 1rem;
    padding: 0;
}

.feature-card li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
    color: var(--color-text-muted);
    text-align: left;
}

.feature-card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

/* Why Us Section */
.why-us {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg-card);
    position: relative;
    overflow: hidden;
}

.why-content {
    max-width: 800px;
    margin: 0 auto;
}

.credibility-line {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: var(--color-text-main);
}

.why-list li {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.why-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

/* How It Works Section */
.how-it-works {
    padding: var(--spacing-xl) 0;
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    position: relative;
}

.step-card {
    position: relative;
    background-color: var(--color-bg-body);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    text-align: center;
}

.step-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

/* CTA Section */
.cta {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(180deg, var(--color-bg-body) 0%, rgba(0, 100, 250, 0.1) 100%);
    text-align: center;
}

.cta-content {
    max-width: 800px;
    margin: 0 auto;
}

.cta-content h2 {
    margin-bottom: 1rem;
}

.cta-content p {
    margin-bottom: 3rem;
    font-size: 1.25rem;
}

.cta-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Footer */
.footer {
    padding: 4rem 0 2rem;
    background-color: var(--color-bg-card);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    margin-bottom: 4rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: var(--color-text-muted);
}

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

.footer-bottom {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.875rem;
    border-top: 1px solid var(--color-border);
    padding-top: 2rem;
}

.footer-tagline {
    font-weight: 600;
    color: var(--color-text-main);
    margin-top: 0.5rem;
    margin-bottom: 0.25rem;
}

.footer-logo-img {
    height: 80px;
    /* Increased 2.5x from 32px */
    width: auto;
    margin-bottom: 0.5rem;
    display: block;
}

.footer-description {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    max-width: 400px;
    line-height: 1.5;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 5rem;
    }

    .header {
        height: var(--header-height-mobile);
    }

    .logo img {
        height: 36px;
    }

    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .nav {
        display: none;
        width: 100%;
    }

    .nav.mobile-visible {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--color-bg-dark);
        padding: 2rem;
        border-bottom: 1px solid var(--color-border);
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero-actions,
    .cta-actions {
        flex-direction: column;
    }

    .steps-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        gap: 2rem;
        text-align: center;
    }

    .footer-links {
        justify-content: center;
        flex-direction: column;
        gap: 1rem;
    }
}