:root {
    --bg-color: #f8fafc;
    --container-bg: #ffffff;
    --text-color: #1e293b;
    --text-muted: #64748b;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --accent-color: #10b981;
    --nav-bg: rgba(255, 255, 255, 0.8);
    --shadow-color: rgba(0, 0, 0, 0.05);
    --border-color: #e2e8f0;
    --card-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --container-bg: #1e293b;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --primary-color: #3b82f6;
    --primary-hover: #60a5fa;
    --nav-bg: rgba(15, 23, 42, 0.8);
    --shadow-color: rgba(0, 0, 0, 0.3);
    --border-color: #334155;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--nav-bg);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary-color);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 15px;
    transition: color 0.3s;
}

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

.theme-toggle button {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.3s;
}

.theme-toggle button:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Main Content */
main {
    margin-top: 70px;
}

.section {
    padding: 100px 0;
}

.bg-light {
    background-color: rgba(0, 0, 0, 0.02);
}

[data-theme="dark"] .bg-light {
    background-color: rgba(255, 255, 255, 0.02);
}

h1, h2, h3 {
    margin-bottom: 20px;
    line-height: 1.2;
}

h2 {
    font-size: 32px;
    text-align: center;
    margin-bottom: 50px;
}

.text-left h2 {
    text-align: left;
}

.section-desc {
    text-align: center;
    color: var(--text-muted);
    margin-top: -30px;
    margin-bottom: 40px;
    font-size: 18px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), #4f46e5);
    color: white;
    padding: 120px 0;
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 20px;
}

.hero p {
    font-size: 20px;
    opacity: 0.9;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-button {
    display: inline-block;
    background-color: white;
    color: var(--primary-color);
    padding: 15px 35px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    font-size: 18px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.2);
}

/* Cards & Content */
.card {
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border-color);
}

.content-box {
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
}

.content-box h3 {
    font-size: 22px;
    margin-top: 30px;
    color: var(--primary-color);
}

.content-box h3:first-child {
    margin-top: 0;
}

.content-box p {
    margin-bottom: 15px;
    color: var(--text-muted);
}

.content-box ul {
    margin-left: 20px;
    margin-bottom: 15px;
    color: var(--text-muted);
}

.content-box li {
    margin-bottom: 10px;
}

/* Form Styles */
.contact-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    font-size: 14px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 15px;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.submit-btn {
    background-color: var(--primary-color);
    color: white;
    padding: 15px;
    border: none;
    border-radius: 10px;
    width: 100%;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.3s;
}

.submit-btn:hover {
    background-color: var(--primary-hover);
}

/* Footer */
.footer {
    padding: 60px 0;
    background-color: var(--container-bg);
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer p {
    color: var(--text-muted);
    margin-bottom: 20px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s;
}

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

/* Modals */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: var(--container-bg);
    margin: 5% auto;
    padding: 40px;
    border-radius: 20px;
    width: 90%;
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.close-modal {
    position: absolute;
    right: 25px;
    top: 20px;
    font-size: 30px;
    font-weight: bold;
    color: var(--text-muted);
    cursor: pointer;
}

.modal-text {
    margin-top: 20px;
    color: var(--text-muted);
    font-size: 15px;
}

.modal-text p {
    margin-bottom: 15px;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .nav-links {
        display: none; /* Simplification for this task */
    }
    
    .hero h1 {
        font-size: 36px;
    }
    
    .section {
        padding: 60px 0;
    }
    
    h2 {
        font-size: 28px;
    }
}