html {
  scroll-behavior: smooth;
}
body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  background: #f5f7fb;
}

/* HEADER */
.header {
  background: #c62828;
  color: white;
  display: flex;
  justify-content: space-between;
  padding: 15px 30px;
}

.header a {
  color: white;
  margin: 0 10px;
  text-decoration: none;
}

/* BANNER */
.banner {
  width: 100%;
}

.banner img {
  width: 100%;
  border-radius: 10px;
}





/* BOX */
.time-box {
  background: rgba(255,255,255,0.6);
  backdrop-filter: blur(6px);

  padding: 15px;
  border-radius: 10px;
  width: 80px;

  font-size: 26px;
  font-weight: bold;

  box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.time-box small {
  font-size: 13px;
}
.time-box {
  transition: transform 0.3s;
}

.time-box.change {
  transform: rotateX(360deg);
}

/* BUTTON */
.btn-main {
  background: #8d6e63;
  color: white;
  padding: 10px 25px;
  border-radius: 8px;
}

.btn-main:hover {
  background: #6d4c41;
}
/* BUTTON */
.btn-main {
  background: #1976d2;
  color: white;
  padding: 12px 25px;
  border-radius: 8px;
  cursor: pointer;
  border: none;
}

/* CARD */
.card {
  background: white;
  padding: 20px;
  border-radius: 12px;
  margin: 20px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* GRID */
.grid {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.grid .card {
  flex: 1;
}

/* BXH */
.leaderboard {
  max-width: 900px;
  margin: auto;
}

.rank-item {
  display: flex;
  justify-content: space-between;
  background: white;
  padding: 15px;
  margin: 10px 0;
  border-radius: 10px;
}

.rank-item.top1 {
  background: #ffe082;
}

.rank-item.top2 {
  background: #e0e0e0;
}

.rank-item.top3 {
  background: #ffccbc;
}

/* FOOTER */
.footer {
  background: #c62828;
  color: white;
  padding: 30px;
  margin-top: 40px;
}

/* SECTION TITLE */
.section-title {
  text-align: center;
  font-size: 24px;
  margin-top: 40px;
}
#podium .col {
  transition: transform 0.3s;
}
#podium .col:hover {
  transform: translateY(-5px);
}
.navbar {
  background: rgba(255, 255, 255, 0.85) !important;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

/* chữ menu */
.navbar .nav-link {
  color: #333 !important;
  font-weight: 500;
}

/* hover */
.navbar .nav-link:hover {
  color: #1976d2 !important;
}

/* logo text */
.navbar-brand {
  color: #1976d2 !important;
}
footer {
  background: linear-gradient(135deg, #f8d898, #eca10b);
  color: #333;
}

footer p {
  margin: 4px 0;
  color: #000000;
}

/* logo không bị chìm */
footer img {
  filter: brightness(0.9);
}
footer h5 {
  color: #000000;
}

footer iframe {
  border-radius: 8px;
}
.banner-img {
  height: 500px;
  object-fit: cover;
  filter: brightness(0.75);
}

.banner-overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  
  text-align: center;
  color: white;

  background: rgba(245, 190, 190, 0.45);
  padding: 20px 30px;
  border-radius: 12px;

  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);

  box-shadow: 0 5px 20px rgba(0,0,0,0.3);
}

.banner-overlay h1 {
  font-size: 48px;
  font-weight: bold;
}

.banner-overlay p {
  font-size: 20px;
  opacity: 0.9;
}

/* animation nhẹ */
.carousel-item {
  transition: opacity 1s ease-in-out;
}

/* button đẹp hơn */
.banner-overlay .btn {
  padding: 10px 25px;
  font-size: 16px;
}
.carousel-item {
  transition: opacity 1s ease-in-out;
}

.carousel-item img {
  transform: scale(1);
  transition: transform 6s linear;
}

/* zoom nhẹ khi active */
.carousel-item.active img {
  transform: scale(1.05);
}
/* KHUNG COUNTDOWN */
.countdown {
  background: linear-gradient(135deg, #f5d7a1, #e0b45c);
  color: #4e342e;

  padding: 35px;
  border-radius: 16px;
  text-align: center;

  max-width: 850px;
  margin: 80px auto 40px; /* 👉 tách khỏi banner */

  box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

/* GRID */
#countdown {
  display: flex;
  justify-content: center;
  gap: 15px;
}

/* BOX */
.time-box {
  background: rgba(255,255,255,0.6);
  backdrop-filter: blur(6px);

  padding: 15px;
  border-radius: 10px;
  width: 80px;

  font-size: 26px;
  font-weight: bold;

  box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.time-box small {
  font-size: 13px;
}

/* BUTTON */
.btn-main {
  background: #8d6e63;
  color: white;
  padding: 10px 25px;
  border-radius: 8px;
}

.btn-main:hover {
  background: #6d4c41;
}
.section-title {
  text-align: center;
  font-weight: bold;
  margin-bottom: 30px;
}

/* GRID */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px,1fr));
  gap: 20px;
}

/* CARD */
.card {
  background: white;
  padding: 20px;
  border-radius: 12px;
  text-align: center;

  box-shadow: 0 5px 20px rgba(0,0,0,0.08);
  transition: all 0.3s;
}

/* hover nâng lên */
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

/* title */
.card h3 {
  color: #1976d2;
  margin-bottom: 10px;
}.countdown {
  position: relative;
  top: -60px;
}
.time-box {
  transition: transform 0.3s;
}

.time-box.change {
  transform: rotateX(360deg);
}
/* CURRENT EXAM */
.current-exam-box{
  background: linear-gradient(135deg,#fff8e1,#ffe0b2);
  padding:30px;
  border-radius:20px;
  box-shadow:0 5px 20px rgba(0,0,0,0.1);
}

.exam-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(200px,1fr));
  gap:20px;
  margin-top:20px;
}

.exam-item{
  background:white;
  padding:20px;
  border-radius:15px;
  text-align:center;
}

/* TIMELINE */
.timeline{
  display:flex;
  gap:20px;
  overflow:auto;
  padding:20px 0;
}

.timeline-item{
  min-width:220px;
  background:white;
  border-radius:16px;
  padding:20px;
  box-shadow:0 5px 15px rgba(0,0,0,0.08);
  border:3px solid #eee;
}

.timeline-item.active{
  border-color:#ff9800;
  background:#fff3e0;
}

/* TOP UNIT */
.top-unit-box{
  background:white;
  padding:25px;
  border-radius:18px;
  box-shadow:0 5px 20px rgba(0,0,0,0.08);
}

/* =========================
   GALLERY REEL
========================= */

.gallery-reel{
  overflow:hidden;
  position:relative;
  width:100%;
  padding:10px 0;
}

.gallery-track{
  display:flex;
  gap:18px;
  width:max-content;

  animation: reelMove 35s linear infinite;
}

.gallery-track img{
  width:260px;
  height:170px;

  object-fit:cover;

  border-radius:18px;

  flex-shrink:0;

  box-shadow:0 5px 15px rgba(0,0,0,0.15);

  transition:0.3s;
}

/* hover */
.gallery-track img:hover{
  transform:scale(1.05);
}

/* animation */
@keyframes reelMove{
  0%{
    transform:translateX(0);
  }

  100%{
    transform:translateX(-50%);
  }
}
.gallery-reel::before,
.gallery-reel::after{
  content:"";
  position:absolute;
  top:0;
  width:80px;
  height:100%;
  z-index:2;
}

.gallery-reel::before{
  left:0;
  background:linear-gradient(to right,#f5f7fb,transparent);
}

.gallery-reel::after{
  right:0;
  background:linear-gradient(to left,#f5f7fb,transparent);
}

/* =========================
   EXAM QUESTION
========================= */

#qTitle{
  text-align:left;
  font-size:24px;
  line-height:1.5;
  font-weight:700;
  color:#222;

  margin-bottom:25px;
}

/* LIST ANSWER */
#options{
  display:flex;
  flex-direction:column;
  gap:16px;
}

/* ITEM */
.answer-item{
  display:block;
  cursor:pointer;
  user-select:none;
}

/* ẨN RADIO/CHECKBOX GỐC */
.answer-input{
  display:none;
}

/* KHUNG */
.answer-content{
  display:flex;
  align-items:flex-start;

  gap:15px;

  padding:18px 20px;

  border:2px solid #dfe3ea;
  border-radius:16px;

  background:white;

  transition:0.25s;

  box-shadow:0 3px 10px rgba(0,0,0,0.04);
}

/* HOVER */
.answer-item:hover .answer-content{
  border-color:#1976d2;
  transform:translateY(-2px);

  box-shadow:0 8px 18px rgba(25,118,210,0.15);
}

/* KHI CHỌN */
.answer-input:checked + .answer-content{
  background:#e3f2fd;
  border-color:#1976d2;

  box-shadow:0 10px 22px rgba(25,118,210,0.2);
}

/* Ô A B C D */
.answer-letter{
  min-width:42px;
  height:42px;

  display:flex;
  align-items:center;
  justify-content:center;

  border-radius:12px;

  background:#1976d2;
  color:white;

  font-weight:700;
  font-size:18px;

  flex-shrink:0;
}

/* TEXT */
.answer-text{
  flex:1;

  text-align:left;

  font-size:18px;
  line-height:1.6;

  color:#222;
}

/* MOBILE */
@media(max-width:768px){

  #qTitle{
    font-size:20px;
  }

  .answer-content{
    padding:16px;
  }

  .answer-text{
    font-size:17px;
  }

  .answer-letter{
    width:38px;
    height:38px;
    font-size:16px;
  }

}
/* =========================
   EXAM INFO CARD (THÍ SINH)
========================= */

.exam-info-card{
  max-width: 650px;
  margin: 30px auto;

  background: linear-gradient(135deg,#ffffff,#f3f8ff);

  border-radius: 18px;

  box-shadow: 0 12px 35px rgba(0,0,0,0.12);

  border: 1px solid rgba(25,118,210,0.15);

  padding: 30px;
}

/* TITLE */
.exam-info-card h4{
  text-align:center;
  font-weight:700;
  margin-bottom:25px;
  color:#1976d2;
}

/* LABEL */
.exam-info-card label{
  font-weight:600;
  margin-top:10px;
  margin-bottom:6px;
  color:#333;
}

/* INPUT */
.exam-info-card .form-control,
.exam-info-card select{
  border-radius:12px;
  padding:12px 14px;
  border:1px solid #d0d7e2;

  transition:0.2s;
}

.exam-info-card .form-control:focus,
.exam-info-card select:focus{
  border-color:#1976d2;
  box-shadow:0 0 0 3px rgba(25,118,210,0.15);
}

/* BUTTON START */
.exam-info-card .btn-primary{
  width:100%;
  margin-top:20px;

  padding:14px;
  font-size:16px;
  font-weight:700;

  border-radius:12px;

  background: linear-gradient(135deg,#1976d2,#42a5f5);
  border:none;

  box-shadow:0 10px 20px rgba(25,118,210,0.25);

  transition:0.25s;
}

.exam-info-card .btn-primary:hover{
  transform:translateY(-2px);
  box-shadow:0 14px 25px rgba(25,118,210,0.35);
}

/* NOTE TEXT */
.exam-info-card p{
  margin-top:15px;
  font-size:13px;
  text-align:center;
  color:#666;
}
#info,
#examBox{
  transition: all 0.4s ease;
}

#examBox{
  opacity: 0;
  transform: translateY(20px);
}

/* =========================
   REVIEW WRONG ANSWERS
========================= */

.review-item{
  border-radius:16px;

  padding:18px;

  margin-bottom:18px;

  background:#fff5f5;

  border-left:5px solid #dc3545;

  box-shadow:0 5px 15px rgba(0,0,0,0.06);
}

.review-item h5{
  font-weight:700;
  margin-bottom:15px;
}

.review-label{
  font-weight:700;
  margin-top:10px;
}

.review-user{
  background:#ffe5e5;
  padding:12px;
  border-radius:10px;
  color:#c62828;
}

.review-correct{
  background:#e8f5e9;
  padding:12px;
  border-radius:10px;
  color:#2e7d32;
}

.modal-content{
  border-radius:18px;
}