:root {
    --primary-color: #121212;
    --secondary-color: #1E1E1E;
    --accent-color: #03DAC6;
    --text-color: #FFFFFF;
    --shadow-color: rgba(3, 218, 198, 0.2);
    --font-family: 'Poppins', sans-serif;
}

.light-theme {
    --primary-color: #FFFFFF;
    --secondary-color: #F5F5F5;
    --accent-color: #007BFF;
    --text-color: #121212;
    --shadow-color: rgba(0, 123, 255, 0.2);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--primary-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header */
header {
    position: sticky;
    top: 0;
    width: 100%;
    padding: 1rem 5%;
    background: rgba(18, 18, 18, 0.8);
    backdrop-filter: blur(10px);
    z-index: 100;
    border-bottom: 1px solid var(--secondary-color);
    transition: background-color 0.3s ease, border-bottom-color 0.3s ease;
}

.light-theme header {
    background: rgba(255, 255, 255, 0.8);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

nav ul {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 2rem;
}

nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s ease;
}

nav a:hover {
    color: var(--accent-color);
}

#theme-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    transition: color 0.3s ease, transform 0.3s ease;
}

#theme-toggle:hover {
    transform: scale(1.1);
}

/* Main Content */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 5%;
}

section {
    padding: 5rem 0;
}

/* Hero Section */
#hero {
    text-align: center;
    min-height: calc(100vh - 80px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

#hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

#hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: rgba(255, 255, 255, 0.7);
}

.light-theme #hero p {
    color: rgba(0, 0, 0, 0.7);
}

/* Buttons */
.cta-button {
    display: inline-block;
    padding: 0.8rem 1.8rem;
    background: var(--accent-color);
    color: #000;
    text-decoration: none;
    border-radius: 5px;
    font-weight: 600;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow-color);
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px var(--shadow-color);
}

/* Section Titles */
h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 3rem;
}

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

.service-card {
    background: var(--secondary-color);
    padding: 2.5rem 2rem;
    border-radius: 10px;
    text-align: center;
    border: 1px solid transparent;
    transition: transform 0.3s ease, border-color 0.3s ease, background-color 0.3s ease;
}

.service-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

.service-card h3 {
    font-size: 1.5rem;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

/* Pricing Section */
.pricing-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    align-items: center;
}

.pricing-card {
    background: var(--secondary-color);
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    border: 1px solid var(--secondary-color);
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.pricing-card.featured {
    transform: scale(1.05);
    border-color: var(--accent-color);
}

.pricing-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.price {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
}

.pricing-card ul {
    list-style: none;
    margin-bottom: 2rem;
}

.pricing-card li {
    margin-bottom: 0.5rem;
}

/* Instructor Section */
#instructors .instructor-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2rem;
    padding: 2rem;
}

#instructors .instructor-profile {
    background: var(--secondary-color);
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    max-width: 400px;
    border: 1px solid transparent;
    transition: transform 0.3s ease, border-color 0.3s ease, background-color 0.3s ease;
}

#instructors .instructor-profile:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

#instructors .instructor-profile h3 {
    font-size: 1.8rem;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

#instructors .instructor-profile p {
    font-size: 1rem;
    line-height: 1.5;
}

/* Contact Section */
#contact .kakao-consult {
    text-align: center;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

#contact .kakao-consult a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
}

#contact .kakao-consult a:hover {
    color: var(--text-color);
}

#contact form {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

#contact input, #contact textarea {
    width: 100%;
    padding: 1rem;
    background: var(--secondary-color);
    border: 1px solid var(--secondary-color);
    border-radius: 5px;
    color: var(--text-color);
    font-size: 1rem;
    transition: border-color 0.3s ease, background-color 0.3s ease;
}

#contact input:focus, #contact textarea:focus {
    outline: none;
    border-color: var(--accent-color);
}

#contact button {
    align-self: center;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 5%;
    margin-top: 3rem;
    border-top: 1px solid var(--secondary-color);
    transition: border-top-color 0.3s ease;
}

/* Responsive */
@media (max-width: 768px) {
    nav {
        flex-direction: column;
        gap: 1rem;
    }

    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }

    #hero h1 {
        font-size: 2.5rem;
    }

    #hero p {
        font-size: 1rem;
    }
}