:root {
    --bg-color: #0f0f0f;
    --text-color: #ffffff;
    --card-bg: #1a1a1a;
    --card-hover: #222222;
    --header-bg: linear-gradient(135deg, #111, #1e1e1e);
    --btn-bg: #ff2f6e;
    --btn-hover: #ff4f86;
    --subtitle-color: #ccc;
    --border-color: #222;
}

[data-theme="light"] {
    --bg-color: #f8f9fa;
    --text-color: #212529;
    --card-bg: #ffffff;
    --card-hover: #f1f3f5;
    --header-bg: linear-gradient(135deg, #e9ecef, #f8f9fa);
    --btn-bg: #ff2f6e;
    --btn-hover: #ff4f86;
    --subtitle-color: #495057;
    --border-color: #dee2e6;
}

body {
    margin: 0;
    font-family: 'Pretendard', Arial, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
}

.container {
    width: 90%;
    max-width: 1100px;
    margin: auto;
}

header {
    padding: 80px 0;
    text-align: center;
    background: var(--header-bg);
}

h1 {
    font-size: 48px;
    letter-spacing: -1px;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 20px;
    color: var(--subtitle-color);
}

.btn {
    display: inline-block;
    margin-top: 30px;
    padding: 14px 32px;
    background: var(--btn-bg);
    color: white;
    border-radius: 40px;
    text-decoration: none;
    font-weight: bold;
    transition: 0.3s;
}

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

.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--card-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: 10px 20px;
    border-radius: 20px;
    cursor: pointer;
    z-index: 1000;
}

section {
    padding: 80px 0;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.card {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 16px;
    transition: 0.3s;
    border: 1px solid var(--border-color);
}

.card img {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 20px;
}

.card:hover {
    transform: translateY(-5px);
    background: var(--card-hover);
}

.card h3 {
    margin-bottom: 10px;
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: 20px;
}

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

.form-group input, 
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-color);
    color: var(--text-color);
    font-family: inherit;
    box-sizing: border-box;
}

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

footer {
    text-align: center;
    padding: 40px 0;
    color: var(--subtitle-color);
    font-size: 14px;
    border-top: 1px solid var(--border-color);
}