:root {
    --red: #c40018;
    --blue: #0b4ea2;
}

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

html {
    scroll-behavior: smooth;
}

.center {
    text-align: center
}

/* MENU */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: linear-gradient(90deg, var(--red), var(--blue));
    z-index: 1000;
}

nav {
    max-width: 1200px;
    margin: auto;
    display: flex;
    justify-content: center;
    gap: 32px;
    padding: 18px 0;
}

nav a {
    color: #fff;
    text-decoration: none;
    font-weight: bold
}

/* HERO */
.hero {
    margin-top: 20px;
    /* height: 100vh;
    background: url("hero.jpg") center/cover no-repeat; */
}

.bg-desktop {
    width: 100%;
    display: block;
}

.bg-mobile {
    width: 100%;
    display: none;
}

@media (max-width: 768px), (orientation: portrait) {
    .bg-desktop {
        display: none;
    }
    .bg-mobile {
        display: block;
    }
}

/* SECTION */
section {
    padding: 40px 20px
}

.section-inner {
    max-width: 1100px;
    margin: auto
}

h2 {
    margin-bottom: 30px;
    text-align: center;
    font-size: 2em;
    background: linear-gradient(135deg, #ff0000, #5143f5);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-transform: uppercase;
}

.blue-box {
    border: 5px solid #dedede;
    border-radius: 10px;
    padding: 30px 15px;
    background-color: #0676DC;
    color: #fff;
    font-size: 16px;
    line-height: 1.5;
}

/* FORM */
.booking-form {
    max-width: 560px;
    margin: auto;
    background: #fff;
    padding: 40px;
    border-radius: 24px;
    box-shadow: 0 20px 45px rgba(0, 0, 0, .3);
    border-top: 6px solid var(--red);
}

.form-group {
    margin-bottom: 18px
}

.form-group label {
    display: flex;
    gap: 6px;
    font-weight: 600;
    margin-bottom: 6px
}

.required {
    color: var(--red)
}

.error {
    color: var(--red);
    font-size: 13px
}

.error:empty {
    display: none
}

.booking-form input,
.booking-form select,
.booking-form textarea {
    width: 100%;
    padding: 14px 16px;
    border-radius: 16px;
    border: 1px solid #ddd;
    font-size: 16px;
}

textarea {
    resize: none
}

.booking-form select {
    appearance: none;
    background: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%23666666' viewBox='0 0 16 16'><path d='M1.5 5.5l6 6 6-6'/></svg>") no-repeat right 18px center;
    padding-right: 48px;
}

.invalid {
    border-color: var(--red)
}

.booking-form button {
    width: 100%;
    padding: 18px;
    border-radius: 22px;
    font-size: 20px;
    font-weight: bold;
    border: none;
    cursor: pointer;
    color: #fff;
    background: linear-gradient(90deg, var(--red), var(--blue));
}

/* ===== LOADING BUTTON ===== */
button.loading{
  pointer-events:none;
  opacity:0.85;
  position:relative;
}

button.loading::after{
  content:"";
  width:22px;
  height:22px;
  border:3px solid rgba(255,255,255,.5);
  border-top-color:#fff;
  border-radius:50%;
  position:absolute;
  top:50%;
  left:50%;
  transform:translate(-50%,-50%);
  animation:spin .8s linear infinite;
}

@keyframes spin{
  to{transform:translate(-50%,-50%) rotate(360deg)}
}

/* Packages */
.info {
    max-width: 600px;
    padding: 15px;
    line-height: 1.5;
    margin: 0 auto;
}

.info p {
    margin-bottom: 10px;
}

.info ul {
    padding-left: 20px;
}
.packages {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.package-card {
    background: #ffffff;
    padding: 30px;
    border-radius: 20px;
    border: 3px solid #4a9eff;
    transition: transform 0.3s;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}

.package-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 50px rgba(74, 158, 255, 0.3);
}

.package-header {
    background: linear-gradient(135deg, #ff6b6b, #ff4444);
    color: #fff;
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 20px;
    text-align: center;
    font-size: 1.5em;
    font-weight: bold;
}

.package-card > p {
    color: #333;
    font-weight: bold;
}

.package-item {
    margin: 15px 0;
    padding-left: 20px;
    position: relative;
    color: #333;
    line-height: 1.6;
}

.package-item::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #4a9eff;
    font-weight: bold;
}

.voucher {
    background: linear-gradient(135deg, #ff6b6b, #ff4444);
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    margin-top: 20px;
    font-size: 1.3em;
    font-weight: bold;
}

/* ===== QUYỀN LỢI ===== */
.benefits{
    background:#f5f7fa;
}

.benefits ul{
    max-width:700px;
    margin:auto;
    list-style:none;
}

.benefits li{
    text-align:center;
    padding:10px 0;
    font-size:18px;
}

/* ===== FOOTER ===== */
footer{
    background:linear-gradient(180deg,var(--red),var(--blue));
    color:#fff;
    padding:40px;
}

.footer-inner{
    max-width:1000px;
    margin:auto;
    text-align:center;
}

.footer-inner img{
    width:200px;
    margin-bottom:20px;
}

.footer-inner p{
    font-size:14px;
    opacity:.9;
}

/* POPUP */
#successPopup {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, .6);
    align-items: center;
    justify-content: center;
}

.popup-box {
    background: #fff;
    padding: 40px;
    border-radius: 24px;
    text-align: center;
}

.popup-box button {
    margin-top: 20px;
    padding: 12px 24px;
    border-radius: 20px;
    border: none;
    background: var(--red);
    color: #fff;
    font-weight: bold;
}

.checkmark{
  width:64px;
  height:64px;
  border-radius:50%;
  background:linear-gradient(135deg,var(--red),var(--blue));
  color:#fff;
  font-size:38px;
  display:flex;
  align-items:center;
  justify-content:center;
  margin:0 auto 16px;
  animation:pop .5s ease;
}

@keyframes pop{
  0%{transform:scale(0);opacity:0}
  70%{transform:scale(1.2)}
  100%{transform:scale(1);opacity:1}
}


/* ===== LOADING OVERLAY ===== */
#loadingOverlay{
  display:none;
  position:fixed;
  inset:0;
  background:rgba(0,0,0,.55);
  z-index:3000;
  align-items:center;
  justify-content:center;
}

.loading-box{
  background:#fff;
  padding:40px 50px;
  border-radius:26px;
  text-align:center;
  box-shadow:0 30px 60px rgba(0,0,0,.3);
}

.loading-box p{
  margin-top:18px;
  font-weight:600;
  color:#333;
}

/* SPINNER */
.spinner{
  width:46px;
  height:46px;
  border:5px solid #ddd;
  border-top-color:var(--red);
  border-radius:50%;
  animation:spin 1s linear infinite;
}

@keyframes spin{
  to{transform:rotate(360deg)}
}

/* BLUR FORM KHI LOADING */
body.loading .booking-form{
  filter:blur(2px);
  pointer-events:none;
}

@media only screen and (min-width: 992px) {
    body,
    html {
        background-image: url(BG_PC.jpg);
        -webkit-background-size: cover;
        -moz-background-size: cover;
        -o-background-size: cover;
        background-size: cover;
        background-attachment: fixed;
    }
}

/* MOBILE */
@media(max-width:768px) {
    body {
        /* background-image: url(../images/BG_PC.jpg); */
        -webkit-background-size: cover;
        -moz-background-size: cover;
        -o-background-size: cover;
        background-size: cover;
        width: 100%;
        height: 100vh;
        /* background-size: 100% 100%; */
        /* background-attachment: scroll; */
    }

    body:after {
        content: "";
        position: fixed;
        /* stretch a fixed position to the whole screen */
        top: 0;
        height: 100vh;
        /* fix for mobile browser address bar appearing disappearing */
        left: 0;
        right: 0;
        z-index: -1;
        /* needed to keep in the background */
        background: url(BG_mobile.jpg);
        -webkit-background-size: cover;
        -moz-background-size: cover;
        -o-background-size: cover;
        background-size: cover;
    }
    nav {
        flex-wrap: wrap;
        gap: 18px
    }
}