* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Pretendard', sans-serif;
}

body {
    line-height: 1.6;
    color: #333;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: auto;
}

.header {
    background: #111;
    color: #fff;
    padding: 15px 0;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav a {
    color: #fff;
    margin-left: 20px;
    text-decoration: none;
}

.hero {
    background: linear-gradient(to right, #005bea, #00c6fb);
    color: white;
    text-align: center;
    padding: 80px 20px;
}

.btn {
    display: inline-block;
    margin-top: 20px;
    padding: 12px 25px;
    background: #fff;
    color: #005bea;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
}

.btn.outline {
    background: transparent;
    border: 2px solid #fff;
    color: #fff;
}

.features {
    padding: 60px 0;
    text-align: center;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-top: 30px;
}

.feature-item {
    background: #f4f4f4;
    padding: 30px;
    border-radius: 10px;
}

.review {
    padding: 60px 0;
    background: #fafafa;
    text-align: center;
}

.contact {
    padding: 60px 0;
    text-align: center;
    background: #005bea;
    color: white;
}

.footer {
    background: #111;
    color: #fff;
    text-align: center;
    padding: 20px 0;
}

/* ========================= */
/* 📱 반응형 (모바일 대응) */
/* ========================= */

@media (max-width: 992px) {
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {

    .header .container {
        flex-direction: column;
    }

    .nav {
        margin-top: 10px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

    .hero {
        padding: 50px 20px;
    }

}

/* ========================= */
/* 🎞 슬라이드 배너 */
/* ========================= */

.slider {
    position: relative;
    width: 100%;
    height: 700px;
    overflow: hidden;
}

.slide {
    position: absolute;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transition: opacity 0.8s ease-in-out;
}

.slide.active {
    opacity: 1;
}

.overlay {
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.4);
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 20px;
}

.overlay h2 {
    font-size: 42px;
}

.overlay p {
    margin-top: 15px;
    font-size: 20px;
}

.prev, .next {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(0,0,0,0.5);
    border: none;
    color: white;
    font-size: 30px;
    padding: 10px 20px;
    cursor: pointer;
}

.prev { left: 20px; }
.next { right: 20px; }

/* 모바일 대응 */
@media (max-width: 768px) {
    .slider {
        height: 400px;
    }

    .overlay h2 {
        font-size: 24px;
    }

    .overlay p {
        font-size: 16px;
    }
}

.youtube-section {
    padding: 60px 0;
    background: #f5f5f5;
}

.youtube-grid {
    width: 90%;
    margin: auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.youtube-item {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 비율 */
    height: 0;
}

.youtube-item iframe {
    position: absolute;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    border-radius: 10px;
}

/* 태블릿 */
@media (max-width: 1024px) {
    .youtube-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 모바일 */
@media (max-width: 768px) {
    .youtube-grid {
        grid-template-columns: 1fr;
    }
}

/* ===== EDULEE 유튜브 SECTION ===== */
.edulee-youtube-wrap {
    padding: 100px 0;
    background: #f7faff;
    text-align: center;
  }
  
  .edulee-youtube-inner {
    width: 90%;
    margin: auto;
  }
  
  .edulee-youtube-title {
    font-size: 36px;
    font-weight: 700;
    color: #002d72;
    margin-bottom: 8px;
  }
  
  .edulee-youtube-sub {
    font-size: 18px;
    color: #415a88;
    margin-bottom: 40px;
  }
  
  .edulee-youtube-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
  }
  
  .edulee-youtube-card {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    box-shadow: 0px 12px 30px rgba(0, 0, 50, 0.15);
    border-radius: 15px;
    overflow: hidden;
    transition: transform 0.3s ease;
  }
  
  .edulee-youtube-card:hover {
    transform: translateY(-8px) scale(1.02);
  }
  
  .edulee-youtube-card iframe {
    position: absolute;
    width: 100%;
    height: 100%;
    border: 0;
    top: 0;
    left: 0;
    border-radius: 15px;
  }
  
  /* 반응형 */
  @media (max-width:1024px) {
    .edulee-youtube-grid {
      grid-template-columns: repeat(2,1fr);
    }
  }
  
  @media (max-width:768px) {
    .edulee-youtube-grid {
      grid-template-columns: 1fr;
    }
    .edulee-youtube-title {
      font-size: 28px;
    }
  }