/* 기본 설정 */
:root {
    --primary-color: #0056b3; /* 신뢰감 있는 딥 블루 */
    --accent-color: #00d4ff; /* 미래지향적인 시안 블루 */
    --text-color: #333;
    --bg-color: #f8f9fa;
}
body {
    margin: 0;
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

/* 헤더 */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 5%;
    background: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary-color);
    letter-spacing: -0.5px;
}

/* 메인 히어로 섹션 */
.hero {
    text-align: center;
    padding: 100px 20px;
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364); /* 수학적 깊이를 표현한 어두운 배경 */
    color: white;
}
.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    font-weight: 700;
}
.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 40px;
}
.hero .highlight {
    color: var(--accent-color);
}
.cta-button {
    display: inline-block;
    padding: 15px 40px;
    background-color: var(--accent-color);
    color: #0f2027;
    font-weight: bold;
    text-decoration: none;
    border-radius: 30px;
    transition: transform 0.2s;
}
.cta-button:hover {
    transform: scale(1.05);
}

/* 특징 섹션 */
.features {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 40px;
    padding: 80px 5%;
    max-width: 1200px;
    margin: 0 auto;
}
.feature-card {
    background: white;
    padding: 40px;
    border-radius: 20px;
    flex: 1;
    min-width: 300px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    text-align: center;
}
.feature-icon {
    font-size: 40px;
    margin-bottom: 20px;
}
.feature-card h3 {
    margin-bottom: 15px;
    font-size: 1.5rem;
}

/* 푸터 */
footer {
    text-align: center;
    padding: 40px;
    background: #e9ecef;
    color: #666;
    font-size: 0.9rem;
}

/* 모바일 대응 */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.5rem; }
}