:root {
  --primary: #c8102e;
  --accent: #ff6600;
  --gold: #f2c94c;
}

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

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
 background: linear-gradient(
  135deg,
#f8fbff 0%,
#dceeff 40%,
#b8dcff 100%
);
  overflow-x: hidden;
}

/* ===================== HEADER ===================== */


header {
    position: fixed;
    
    top: 0;
    left: 0;
    width: 100%;
    z-index: 999;
    background: rgba(255,255,255,0.97);
    backdrop-filter: blur(15px);
    border-bottom: 1px solid rgba(0,0,0,.06);
    transition: .35s ease;
}

header.scrolled{
    box-shadow: 0 10px 35px rgba(0,0,0,.08);
}

/* ================= NAV ================= */

.nav{
    max-width:1300px;
    height:85px;
    margin:auto;
    padding:0 40px;
    display:flex;
    align-items:center;
    justify-content:space-between;
}

/* ================= LOGO ================= */

.logo{
    display:flex;
    align-items:center;
    gap:15px;
    text-decoration:none;
}

.logo img{
    width:60px;
    height:60px;
    object-fit:contain;
    border-radius:50%;
    background:#fff;
    transition:.35s;
}

.logo img:hover{
    transform:rotate(-8deg) scale(1.08);
}

.logo-text{
    display:flex;
    flex-direction:column;
}

.logo-text h2{
    font-size:30px;
    font-weight:800;
    color:#d62828;
    margin:0;
    line-height:1;
    letter-spacing:.5px;
}

.logo-text span{
    font-size:13px;
    color:#666;
    margin-top:5px;
}

/* ================= MENU ================= */

.overlay.active{
    opacity:1;
    visibility:visible;
}

/* Menu */
.nav-links {
    display:flex;
    align-items:center;
    gap:32px;
}

.nav-links a{
    position:relative;
    color:#243b55;
    text-decoration:none;
    font-weight:600;
    transition:.3s;
}

.nav-links a.active{
    color:#c8102e;
}

.nav-links a.active::after{
    content:"";
    position:absolute;
    left:0;
    bottom:-10px;
    width:100%;
    height:3px;
    background:#c8102e;
}

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

.hamburger{
    display:none;
    font-size:28px;
    cursor:pointer;
    color:var(--primary);
}
/* ================= BUTTON ================= */

.nav-btn{

    background:#d62828;
    color:#fff;
    padding:12px 24px;
    border-radius:40px;
    text-decoration:none;
    font-weight:600;
    transition:.3s;
}

.nav-btn:hover{

    background:#b71c1c;
    transform:translateY(-2px);
    box-shadow:0 10px 25px rgba(214,40,40,.3);
}

.modal {
            display: none;
            position: fixed;
            top: 0; left: 0;
            width: 100%; height: 100%;
            background: rgba(0,0,0,0.9);
            z-index: 2000;
            align-items: center;
            justify-content: center;
            padding: 20px;
            box-sizing: border-box;
        }
        .modal-content {
            background: #f8fafc;
            padding: 20px;
            border-radius: 20px;
            width: 100%;
            max-width: 1100px;
            max-height: 95vh;
            overflow: auto;
            position: relative;
            box-shadow: 0 20px 50px rgba(0,0,0,0.5);
        }
        .close-btn {
            position: absolute;
            top: 15px;
            right: 25px;
            font-size: 42px;
            cursor: pointer;
            color: #e11d48;
            z-index: 10;
        }
        .close-btn:hover { color: #f43f5e; }
/* ================= MOBILE ================= */

@media(max-width:767px){

    .nav{
        padding:0 20px;
    }

    .nav-links{
        gap:20px;
    }

    .nav-links a{
        font-size:15px;
    }

}

@media(max-width:767px){

    .nav{
        height:75px;
    }

    .logo img{
        width:48px;
        height:48px;
    }

    .logo-text h2{
        font-size:24px;
    }

}
/* ===================== HERO ===================== */
.hero {
  height: 100vh;
  min-height: 700px;
  display: flex;
  align-items: center;
  position: relative;
 background: linear-gradient(
  135deg,
#f8fbff 0%,
#dceeff 40%,
#b8dcff 100%
);
  color: white;
}

.hero-content {
  max-width: 1300px;
  margin: 0 auto;
  padding: 0 30px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  z-index: 2;
}

.hero-text h1{
    font-size:4.5rem;
    line-height:1.08;
    font-weight:800;
    color:#173B6C;
    letter-spacing:-1px;
    margin-bottom:25px;
    text-shadow:0 8px 20px rgba(0,0,0,.12);
    animation:fadeInUp .9s ease;
}

/* Chữ nổi bật */

.hero-text h1 span{
    color:#D62828;
    position:relative;
}

/* Gạch chân */

.hero-text h1 span::after{

    content:"";
    position:absolute;
    left:0;
    bottom:8px;
    width:100%;
    height:16px;
    background:#FFD54F;
    opacity:.45;
    z-index:-1;
    border-radius:20px;

}

.hero-text p{

    font-size:1.35rem;
    line-height:1.8;
    color:#425466;
    max-width:520px;
    margin:0 0 45px;
    animation:fadeInUp 1s .25s forwards;
    opacity:0;

}


.btn {
  padding: 18px 48px;
  background: linear-gradient(45deg, #ff6b00, #ff8c00);
  color: white;
  border: none;
  border-radius: 50px;
  font-size: 1.3rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 10px 30px rgba(255, 107, 0, 0.5);
  transition: all 0.4s;
  animation: fadeInUp 1s ease 0.6s forwards;
  opacity: 0;
}

.btn:hover {
  transform: translateY(-8px) scale(1.05);
  box-shadow: 0 20px 40px rgba(255, 107, 0, 0.6);
}

.hero-image {
  animation: float 6s ease-in-out infinite;
}

.hero-image img {
  width: 100%;
  max-width: 520px;
  border-radius: 20px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}
.content{
    padding-top:60px;
}

.container{
    max-width:1400px;
    margin:auto;
    padding:20px;
}

.main-title{
    margin-bottom:10px;
    text-align:center;
    color:#c8102e;
    font-size:42px;
}

.subtitle{
    text-align:center;
    margin-bottom:50px;
    color:#555;
}

.section-title{
    margin:40px 0 25px;
    color:#173B6C;
    font-size:30px;
}
/* ===================== TƯ LIỆU PAGE ===================== */

.resource-grid{
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin: 40px 0 80px;
    justify-items: center; /* căn giữa card */
}

.resource-card{
    width: 85%;              /* giảm từ 100% xuống 85% */
    background: #fff;
    border-radius: 18px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0,0,0,.12);
    transition: .35s;
}


.resource-card:hover{

    transform:translateY(-8px);
    box-shadow:0 20px 40px rgba(0,0,0,.18);

}

.resource-card video{

    width:100%;
    aspect-ratio:16/9;
    display:block;
    object-fit:cover;
    background:#000;

}

.resource-card h3{

    padding:18px;
    text-align:center;
    font-size:22px;
    color:#c8102e;

}

/* Tablet */

@media(max-width:1023px){

    .resource-grid{

        grid-template-columns:1fr;

    }

}

.card-img {
    height: 200px;
    background: linear-gradient(135deg, #f8f9fa, #e0f2fe);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
    color: var(--primary);
    position: relative;
}

.card-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.resource-card h3 {
    padding: 20px 20px 10px;
    font-size: 1.25rem;
    color: var(--primary);
}

.resource-card p {
    padding: 0 20px 25px;
    color: #555;
    font-size: 1rem;
    line-height: 1.5;
}
footer {
 background: linear-gradient(
  135deg,
#f8fbff 0%,
#dceeff 40%,
#b8dcff 100%
);
  color: black;
  text-align: center;
  padding: 60px 20px 30px;
}
/* ===================== MOBILE MENU ===================== */
@media (max-width: 767px) {
  .hamburger {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: rgba(255,255,255,0.98);
    flex-direction: column;
    padding: 20px 0;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    display: none;
    gap: 15px;
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links a {
    padding: 10px 0;
    text-align: center;
    font-size: 17px;
  }
}

@media (max-width: 767px) {
  .nav {
    height: 75px;
  }

  .hero {
    min-height: 80vh;
  }

  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }

  .hero-image img {
    max-width: 360px;
  }

  .explore {
    padding: 80px 15px;
  }

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

@media (max-width: 480px) {
  .hero-text h1 {
    font-size: clamp(2rem, 8.5vw, 2.6rem);
  }
}