body {
    background: #dedee0;
}
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(90deg, rgba(26,31,113,0.95) 0%, rgba(39,48,165,0.95) 100%);
  backdrop-filter: blur(6px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  transition: background 0.3s ease;
}
header.shrink {
  padding-top: 5px;
  padding-bottom: 5px;
  background: linear-gradient(90deg, #1a1f71 0%, #2730a5 100%);
  box-shadow: 0 3px 10px rgba(0,0,0,0.3);
}


.navbar {
  background: transparent !important;
}

.navbar .nav-link {
  color: #ffffff !important;
  font-weight: 500;
  transition: color 0.3s ease, transform 0.2s;
}

.navbar .nav-link:hover {
  color: #ffd700 !important; /* vàng nhạt nổi bật */
  transform: translateY(-2px);
}

.navbar-brand {
  color: #fff !important;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.navbar-brand span {
  color: #ffd700; /* tô vàng riêng cho chữ MBX */
}

.navbar-toggler {
  border-color: rgba(255,255,255,0.5);
}

.card {
    border-radius: 16px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
}

.upload-box {
    border: 2px dashed #bbb;
    padding: 15px;
    border-radius: 12px;
    text-align: center;
    background: #fff;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
}

.upload-box:hover {
    border-color: #0d6efd;
    background: #f0f7ff;
}

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 12px;
}


.primary-image {
    width: 100%;
    max-height: 400px;
    overflow: hidden;
    border-radius: 10px;
    position: relative;
    background: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
}

.primary-image img {
    max-width: 100%;
    max-height: 400px;
    object-fit: contain;
    cursor: pointer;
    border-radius: 10px;
    transition: transform 0.3s ease;
}

.primary-image img:hover {
    transform: scale(1.02);
}
.primary-image-card {
  position: relative;
  display: inline-block;
}

.primary-btns {
  position: absolute;
  bottom: 10px;
  right: 10px;
  display: flex;
  gap: 5px;
  background: rgba(0,0,0,0.4);
  padding: 5px;
  border-radius: 6px;
}

.primary-btns .btn {
  font-size: 14px;
  padding: 4px 8px;
}

.gallery {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
    margin-top: 10px;
}

.gallery .image-card {
    position: relative;
    border-radius: 6px;
    overflow: hidden;
    cursor: pointer;
    border: 1px solid #ddd;
    background: #fff;
    transition: transform 0.2s ease;
}

.gallery .image-card:hover {
    transform: scale(1.03);
}

.gallery .image-card img {
    width: 120px;
    height: 80px;
    object-fit: cover;
    border-radius: 6px;
}

.preview-btns {
    position: absolute;
    bottom: 4px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 4px;
    background: rgba(0, 0, 0, 0.5);
    padding: 2px 4px;
    border-radius: 4px;
}

.preview-btns button {
    font-size: 10px;
    padding: 2px 6px;
    color: white;
    background: transparent;
    border: none;
}
/* Lightbox Overlay */
.lightbox-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0,0,0,0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.lightbox-overlay img {
    max-width: 90%;
    max-height: 90%;
}

.lightbox-close {
    position: absolute;
    top: 20px;
    right: 30px;
    font-size: 30px;
    color: white;
    cursor: pointer;
}

.lightbox-prev,
.lightbox-next {
    position: absolute;
    top: 50%;
    font-size: 50px;
    color: white;
    cursor: pointer;
    user-select: none;
    padding: 10px;
    background: rgba(0,0,0,0.3);
    border-radius: 50%;
    transform: translateY(-50%);
}

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


.footer {
    background: #1a1f71;
    color: white;
    padding: 20px 0;
    margin-top: 30px;
}
footer img {
  transition: transform 0.3s ease;
}
footer img:hover {
  transform: scale(1.05);
}

@media (max-width: 576px) {
    .gallery .image-card img {
        width: 80px;
        height: 60px;
    }

    .primary-image img {
        max-height: 250px;
    }
}

@media (max-width: 768px) {
    .primary-image img {
        max-height: 300px;
    }
}

/* 🌟 Tab style hiện đại */
 /* Nền cho vùng chứa tab */
.custom-tabs {
  background-color: #f8f9fa; /* xám nhạt nhẹ */
  border-radius: 8px 8px 0 0;
  padding: 6px 10px;
}

/* Tab mặc định */
.custom-tabs .nav-link {
  color: #555;
  border: none;
  border-radius: 8px 8px 0 0;
  margin-right: 4px;
  background-color: #e9ecef; /* nền xám nhẹ */
  transition: all 0.2s ease;
}

/* Hover */
.custom-tabs .nav-link:hover {
  background-color: #dee2e6;
  color: #000;
}

/* Tab đang active */
.custom-tabs .nav-link.active {
  background-color: #1a1f71; /* xanh MBX */
  color: #fff !important;
  font-weight: 600;
}