:root {
    /* Palette - Slate & Indigo */
    --color-bg: #f8fafc;
    --color-bg-alt: #f1f5f9;
    --color-surface: #ffffff;

    --color-text-main: #334155;
    --color-text-muted: #64748b;
    --color-heading: #0f172a;

    --color-primary: #6366f1;
    /* Indigo 500 */
    --color-primary-dark: #4f46e5;
    /* Indigo 600 */
    --color-primary-light: #818cf8;
    /* Indigo 400 */

    --color-border: #e2e8f0;

    /* Spacing */
    --container-width: 1200px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 8rem;

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);

    /* Radius */
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

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

html {
    scroll-behavior: smooth;
}

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

h1,
h2,
h3,
h4,
h5,
h6 {
    color: var(--color-heading);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.025em;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
}

ul {
    list-style: none;
}

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

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

.text-center {
    text-align: center;
}

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

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

/* Components */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid transparent;
    gap: 0.5rem;
}

.btn-primary {
    background-color: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

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

.btn-outline {
    background-color: transparent;
    border-color: var(--color-border);
    color: var(--color-heading);
}

.btn-outline:hover {
    border-color: var(--color-heading);
    background-color: white;
}

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

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: rgba(248, 250, 252, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.6);
    padding: 1rem 0;
    transition: all 0.3s ease;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-heading);
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.logo span {
    color: var(--color-primary);
}

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

.main-nav a:not(.btn) {
    font-weight: 500;
    color: var(--color-text-muted);
}

.main-nav a:not(.btn):hover {
    color: var(--color-primary);
}

/* Hero Section */
.hero {
    padding: 10rem 0 6rem;
    position: relative;
    overflow: hidden;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, var(--color-heading), var(--color-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    margin-bottom: 2.5rem;
    max-width: 540px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
}

.hero-stats {
    display: flex;
    gap: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.stat-item strong {
    display: block;
    font-size: 1.5rem;
    color: var(--color-heading);
}

.stat-item span {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.hero-visual {
    position: relative;
}

.visual-card {
    background: white;
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    position: relative;
    z-index: 1;
    animation: float 6s ease-in-out infinite;
}

.visual-bg {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 120%;
    height: 120%;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, rgba(248, 250, 252, 0) 70%);
    z-index: 0;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-20px);
    }
}

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

.section-header {
    max-width: 600px;
    margin: 0 auto 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all 0.3s ease;
}

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

.feature-icon {
    width: 48px;
    height: 48px;
    background-color: rgba(99, 102, 241, 0.1);
    color: var(--color-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

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

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

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 4rem;
    margin-bottom: 4rem;
}

.footer-brand p {
    margin-top: 1rem;
    color: var(--color-text-muted);
    max-width: 300px;
}

.footer-col h4 {
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

.footer-col ul {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

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

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

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

/* Mobile Menu */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 6px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-heading);
    transition: all 0.3s;
}

/* Responsive */
@media (max-width: 768px) {
    .site-header .main-nav {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: white;
        padding: 2rem;
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-150%);
        transition: transform 0.3s ease;
        z-index: 999;
    }

    .site-header .main-nav.active {
        transform: translateY(0);
    }

    .main-nav ul {
        flex-direction: column;
        align-items: flex-start;
    }

    .menu-toggle {
        display: flex;
    }

    .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        margin: 0 auto 2rem;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

/* Modal Overlay */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(8px);
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.modal-container {
    background-color: white;
    width: 90%;
    max-width: 800px;
    height: 80%;
    max-height: 600px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    transform: scale(0.95);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-overlay.active .modal-container {
    transform: scale(1);
}

.modal-header {
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    font-size: 1.5rem;
}

.modal-body {
    padding: 3rem 2rem;
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.converter-box {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.conv-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    align-items: center;
}

.conv-group label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--color-heading);
}

.conv-group input {
    max-width: 120px;
    text-align: center;
    font-size: 1.25rem;
    font-weight: 700;
}

.conv-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1.5rem;
    align-items: center;
}

.conv-col {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.conv-col label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    text-align: center;
}

.conv-col input {
    font-size: 2.5rem;
    font-weight: 800;
    text-align: center;
    padding: 1rem;
    color: var(--color-primary);
    background-color: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
}

.conv-col input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.conv-arrow {
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
    padding-top: 1.5rem;
}

.conv-result {
    text-align: center;
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-text-muted);
    padding: 1.5rem;
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-md);
}

@media (max-width: 600px) {
    .conv-grid {
        grid-template-columns: 1fr;
    }

    .conv-arrow {
        justify-content: center;
        padding: 0;
        transform: rotate(90deg);
    }

    .modal-container {
        height: 95%;
        max-height: none;
    }
}