html,
body {
  margin: 0;
  padding: 0;
  border: 0;
}

:root {
  --primary: #0066cc;
  --secondary: #00b39f;
  --dark: #0f172a;
  --white: #ffffff;
  --light: #f5f7fa;
  --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  --footer-bg: #003d7c;
  --footer-light: #52c2ff;
  --footer-text: #e0f7ff;
}


* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
  scroll-behavior: smooth;
}


body {
  background-color: var(--light);
  color: var(--dark);
  line-height: 1.6;
  overflow-x: hidden;
}



header {
  background:  linear-gradient(135deg, #00b4d8, #0077b6);
  color: white;
  padding: 0; /* Xóa padding 14px 0 để kiểm soát bằng .nav */
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav {
  max-width: 1150px;
  margin: auto;
  display: flex;
  justify-content: space-between;
  align-items: center; 
  padding: 8px 20px; 
}


.brand {
  display: flex;
  align-items: center;
  gap: 15px; 
  letter-spacing: 0.5px;
}
.brand-info {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 22px;
}

nav a {
  color: white;
  font-weight: 600;
  text-decoration: none;
  position: relative;
  transition: 0.3s;
}

nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 2px;
  background: white;
  transition: width 0.3s;
}

nav a:hover::after {
  width: 100%;
}


.hero {
  background: linear-gradient(rgba(0, 70, 160, 0.75), rgba(0, 179, 159, 0.75)),
    url('download.jfif');
  background-size: cover;
  background-position: center;
  color: white;
  text-align: center;
  padding: 130px 20px 100px;
  position: relative;
}

.hero h1 {
  font-size: 46px;
  font-weight: 800;
  margin-bottom: 16px;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.hero p {
  font-size: 18px;
  max-width: 820px;
  margin: 0 auto;
  opacity: 0.95;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}


.hero-actions {
  margin-top: 38px;
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}

.btn-primary {
  background:   linear-gradient(135deg, #00b4d8, #0077b6);
  color: #fff;
  padding: 14px 34px;
  border-radius: 50px;
  font-weight: 700;
  text-decoration: none;
  transition: all 0.3s ease;
  box-shadow: 0 6px 18px rgba(0, 119, 182, 0.4);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0096c7, #023e8a);
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(0, 119, 182, 0.6);
  filter: brightness(1.15);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border: 2px solid #fff;
  padding: 13px 30px;
  border-radius: 50px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s ease;
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-3px);
  box-shadow: 0 4px 15px rgba(255, 255, 255, 0.3);
}


.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 25px;
  max-width: 1150px;
  margin: 70px auto;
  padding: 0 20px;
}

.feature {
  background: white;
  border-radius: 14px;
  padding: 30px 25px;
  box-shadow: var(--shadow);
  text-align: center;
  transition: 0.3s;
}

.feature:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.feature .icon {
  font-size: 38px;
  color: var(--primary);
  margin-bottom: 12px;
}

.feature h4 {
  color: var(--primary);
  margin-bottom: 6px;
  font-size: 18px;
}

.feature p {
  color: var(--dark);
  font-size: 15px;
  opacity: 0.85;
  margin-top: 5px;
  line-height: 1.5;
}

/* ===== ROOMS ===== */
.rooms {
  background: var(--white);
  padding: 70px 20px;
}

.rooms h3 {
  text-align: center;
  color: var(--primary);
  margin-bottom: 40px;
  font-size: 26px;
  font-weight: 700;
}

.rooms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  max-width: 1150px;
  margin: auto;
}

.room {
  background: var(--light);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: 0.3s;
}

.room:hover {
  transform: translateY(-6px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.room img {
  width: 100%;
  height: 190px;
  object-fit: cover;
}

.room-body {
  padding: 16px;
}

.room-body h4 {
  color: var(--primary);
  margin-bottom: 6px;
}

.room-footer {
  background: var(--primary);
  color: white;
  padding: 10px;
  text-align: center;
  font-weight: 600;
}


.slider {
  position: relative;
  width: 80%;
  max-width: 900px;
  overflow: hidden;
  border-radius: 15px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  margin: 50px auto;
}

.slides {
  display: flex;
  transition: transform 0.8s ease;
}

.slides img {
  width: 100%;
  border-radius: 15px;
}

.btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background-color: rgba(0, 0, 0, 0.5);
  color: white;
  border: none;
  padding: 10px 15px;
  cursor: pointer;
  border-radius: 50%;
  font-size: 18px;
  user-select: none;
}

.btn:hover {
  background-color: rgba(0, 0, 0, 0.8);
}

.prev {
  left: 15px;
}

.next {
  right: 15px;
}


.main-footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  padding: 60px 20px 20px;
  font-size: 15px;
  line-height: 1.6;
}

.footer-content {
  max-width: 1150px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-column {
  min-width: 250px;
  margin-bottom: 30px;
  flex-basis: calc(33.33% - 40px);
}

.footer-column h3 {
  font-size: 1.3em;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--footer-light);
  position: relative;
}


.footer-column h3::after {
  content: '';
  display: block;
  width: 40px;
  height: 3px;
  background-color: var(--footer-light);
  margin-top: 5px;
}


.footer-logo {
  width: 120px;
  height: auto;
  margin-bottom: 15px;
}

.footer-title {
  font-size: 1.5em;
  margin: 0 0 5px;
}

.footer-slogan {
  font-size: 0.9em;
  opacity: 0.8;
}

.footer-social {
  margin-top: 20px;
  display: flex;
  gap: 15px;
  align-items: center;
}

.social-icon {
  width: 32px;
  height: 32px;
  filter: brightness(0) invert(1);
  transition: 0.3s;
  object-fit: contain;
}

.social-icon-fa {
  font-size: 20px;
  color: #ffffff;
  width: auto;
  height: auto;
  padding: 6px;
  border: 1px solid #ffffff;
  border-radius: 50%;
  transition: 0.3s;
}

.footer-social a:hover .social-icon,
.footer-social a:hover .social-icon-fa {
  transform: scale(1.1);
  opacity: 0.9;
  color: #ffffff;
  border-color: #ffffff;
}


.footer-contact ul {
  list-style: none;
  padding: 0;
}

.footer-contact ul li {
  display: flex;
  align-items: flex-start;
  margin-bottom: 15px;
}

.footer-contact ul li i {
  font-size: 1em;
  color: var(--footer-light);
  margin-right: 15px;
  margin-top: 3px;
}

.footer-contact ul li p {
  margin: 0;
  flex-grow: 1;
}

.footer-contact a {
  color: var(--footer-light);
  text-decoration: none;
  transition: 0.3s;
}

.footer-contact a:hover {
  color: var(--white);
  text-decoration: underline;
}

.footer-org-name {
  font-size: 1em;
  font-weight: 600;
  margin-bottom: 15px;
  color: var(--white);
}


.footer-links ul {
  list-style: none;
  padding: 0;
}

.footer-links ul li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--footer-text);
  text-decoration: none;
  transition: 0.3s;
  position: relative;
  padding-left: 15px;
}

.footer-links a:hover {
  color: var(--footer-light);
}

.footer-links a::before {
  content: '▶';
  position: absolute;
  left: 0;
  font-size: 0.7em;
  color: var(--footer-light);
}

.footer-bottom {
  text-align: center;
  margin-top: 20px;
  font-size: 0.85em;
  opacity: 0.7;
}


@media (max-width: 992px) {
  .footer-content {
    justify-content: space-around;
  }

  .footer-column {
    flex-basis: calc(50% - 20px);
  }

  .footer-brand-column {
    flex-basis: 100%;
    text-align: center;
  }

  .footer-brand-column .footer-logo,
  .footer-brand-column .footer-social {
    margin-left: auto;
    margin-right: auto;
    justify-content: center;
  }

  .footer-column h3::after {
    margin-left: auto;
    margin-right: auto;
  }
}

@media (max-width: 576px) {
  .main-footer {
    padding-top: 20px;
  }

  .footer-column {
    flex-basis: 100%;
    text-align: center;
  }

  .footer-column h3 {
    font-size: 1.1em;
    text-align: center;
  }

  .footer-column h3::after {
    left: 50%;
    transform: translateX(-50%);
    margin: 5px auto 0;
  }

  .footer-contact ul li {
    justify-content: center;
  }

  .footer-contact ul li i {
    margin-right: 10px;
  }

  .footer-links a {
    padding-left: 0;
  }

  .footer-links a::before {
    content: none;
  }
}

@media (max-width: 768px) {
  .hero h1 {
    font-size: 34px;
  }

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

  nav ul {
    gap: 14px;
  }
}

.member-banner {

  background: none; 
  display: flex;
  flex-direction: row; 
  align-items: center; 
  gap: 5px; 
  justify-content: center;
  padding: 0; 
  color: white;
  font-weight: 500; 
  font-size: 13px;
  line-height: 1.2;
}

.member-banner img {
  height: 30px;
  width: auto;
  vertical-align: middle;
  filter: brightness(0) invert(1); 
  margin-top: 5px; 
}


@media (max-width: 768px) {
  
  .brand {
    flex-direction: column; 
    align-items: flex-start;
    gap: 5px;
  }

  .member-banner {
    flex-direction: row;
    font-size: 12px;
  }

  .member-banner img {
    height: 25px;
    margin-top: 0;
  }
}
/* ========================================= */
/* CSS cho phần "Cách sử dụng website" - Video Thumbnail */
/* ========================================= */

.how-to-use {
    padding: 60px 0; /* Khoảng cách trên dưới */
    text-align: center;
    background-color: #f8f8f8; /* Màu nền nhẹ cho section */
}

.how-to-use .rooms-header h3 {
    font-size: 2.5em;
    color: #333;
    margin-bottom: 40px;
    position: relative;
    padding-bottom: 10px;
}

.how-to-use .rooms-header h3::after {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    bottom: 0;
    width: 80px;
    height: 4px;
    background-color: #007bff; /* Màu xanh nổi bật */
    border-radius: 2px;
}

.video-container {
    width: 100%;
    max-width: 800px; /* Tăng kích thước tối đa cho video */
    margin: 0 auto; /* Căn giữa container */
    background-color: #000; /* Nền đen bao quanh để tạo cảm giác video */
    border-radius: 12px; /* Bo góc nhẹ cho toàn bộ khối video */
    overflow: hidden; /* Đảm bảo mọi thứ bên trong không tràn ra */
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2); /* Tạo bóng đổ nhẹ */
    position: relative; /* Quan trọng để định vị nút play */
}

.video-thumbnail {
    display: block; /* Để liên kết chiếm toàn bộ không gian */
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* Tỷ lệ khung hình 16:9 (chiều cao = 56.25% chiều rộng) */
    overflow: hidden;
    cursor: pointer;
}

.video-thumbnail img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover; /* Đảm bảo hình ảnh che phủ toàn bộ mà không bị biến dạng */
    transition: transform 0.3s ease; /* Hiệu ứng zoom nhẹ khi hover */
}

.video-thumbnail:hover img {
    transform: scale(1.05); /* Zoom ảnh nhẹ khi hover */
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 90px; /* Kích thước nút play lớn hơn */
    height: 90px; /* Kích thước nút play lớn hơn */
    background-color: rgba(255, 0, 0, 0.9); /* Màu đỏ YouTube, hơi trong suốt */
    border-radius: 50%; /* Hình tròn */
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s ease, transform 0.3s ease; /* Hiệu ứng hover */
    z-index: 10; /* Đảm bảo nút play nằm trên ảnh */
}

.play-button::before {
    content: '';
    position: absolute;
    width: 0;
    height: 0;
    border-top: 20px solid transparent; /* Kích thước mũi tên lớn hơn */
    border-bottom: 20px solid transparent;
    border-left: 35px solid white; /* Mũi tên màu trắng */
    margin-left: 8px; /* Dịch mũi tên sang phải một chút */
}

.video-thumbnail:hover .play-button {
    background-color: rgba(255, 0, 0, 1); /* Đậm hơn khi hover */
    transform: translate(-50%, -50%) scale(1.1); /* Nút play cũng phóng to nhẹ */
}

/* ========================================= */
/* Media Queries cho Responsive (Nếu cần) */
/* ========================================= */
@media (max-width: 768px) {
    .how-to-use .rooms-header h3 {
        font-size: 2em;
        margin-bottom: 30px;
    }

    .play-button {
        width: 70px;
        height: 70px;
    }
    .play-button::before {
        border-top: 12px solid transparent;
        border-bottom: 12px solid transparent;
        border-left: 20px solid white;
        margin-left: 6px;
    }
}

@media (max-width: 480px) {
    .how-to-use {
        padding: 40px 0;
    }
    .how-to-use .rooms-header h3 {
        font-size: 1.8em;
        margin-bottom: 25px;
    }
    .play-button {
        width: 60px;
        height: 60px;
    }
    .play-button::before {
        border-top: 10px solid transparent;
        border-bottom: 10px solid transparent;
        border-left: 18px solid white;
        margin-left: 5px;
    }
}