:root {
    --primary-color: #00aaff;
    --secondary-color: #aa00ff;
    --background-color: #121212;
    --surface-color: rgba(255, 255, 255, 0.05);
    --on-surface-color: #ffffff;
    --glow-color: rgba(0, 170, 255, 0.7);

    --font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* General Styles & Resets */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--on-surface-color);
    overflow-x: hidden;
    background-image: radial-gradient(circle at 10% 20%, rgba(0, 170, 255, 0.1), transparent 30%),
                      radial-gradient(circle at 90% 80%, rgba(170, 0, 255, 0.1), transparent 30%);
    background-attachment: fixed;
}

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

a:hover {
    color: var(--secondary-color);
}

/* Header */
header {
    background-color: rgba(18, 18, 18, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto;
}

.logo a {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--on-surface-color);
    letter-spacing: -1px;
}

nav ul {
    list-style: none;
    display: flex;
}

nav ul li {
    margin-left: 3rem;
}

nav ul li a {
    font-weight: 500;
    font-size: 1rem;
}

/* Hero Section */
.hero {
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 8rem 2rem;
    min-height: 80vh;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

.hero-content {
    max-width: 800px;
}

.hero-content h1 {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    color: #fff;
}

.hero-content p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    color: rgba(255, 255, 255, 0.8);
}

.cta-button {
    background: var(--on-surface-color);
    color: var(--background-color);
    padding: 1rem 2.5rem;
    border-radius: 50px;
    font-weight: bold;
    font-size: 1.1rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 0 20px rgba(0,0,0,0.2);
}

.cta-button:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px var(--glow-color);
    color: var(--primary-color);
}

/* Sections */
.features, .pricing, .contact {
    padding: 6rem 2rem;
    text-align: center;
    max-width: 1400px;
    margin: 0 auto;
}

section h2 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 4rem;
}

/* Glassmorphism Cards */
.feature, .pricing-plan {
    background: var(--surface-color);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: 2.5rem;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature:hover, .pricing-plan:hover {
    transform: translateY(-10px);
    box-shadow: 0 0 40px var(--glow-color);
}

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

.feature i {
    font-size: 3rem;
    background: -webkit-linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1.5rem;
}

.feature h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

/* Pricing Section */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
    align-items: center;
}

.pricing-plan.recommended {
    border: 2px solid var(--primary-color);
    transform: scale(1.05);
}

.pricing-plan h3 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.price {
    font-size: 3rem;
    font-weight: bold;
    margin-bottom: 1.5rem;
}

.price span {
    font-size: 1rem;
    font-weight: normal;
    color: rgba(255, 255, 255, 0.7);
}

.pricing-plan ul {
    list-style: none;
    margin-bottom: 2.5rem;
}

.pricing-plan ul li {
    margin-bottom: 1rem;
}

.pricing-plan .cta-button {
    background: var(--primary-color);
    color: #fff;
}

.pricing-plan .cta-button:hover {
    background: #fff;
    color: var(--primary-color);
    box-shadow: 0 0 25px var(--glow-color);
}

/* Contact Section */
.contact p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* Footer */
footer {
    background-color: #1a1a1a;
    color: rgba(255, 255, 255, 0.7);
    text-align: center;
    padding: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Responsive */
@media (max-width: 768px) {
    nav ul {
        display: none; /* Or implement a hamburger menu */
    }

    .hero-content h1 {
        font-size: 2.8rem;
    }

    section h2 {
        font-size: 2.5rem;
    }
}