*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
html{
	scroll-behavior: smooth;
}
body{
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #d6d2cf, #c1b7b0, #a89f99, #8c8680);
    background-size: 400% 400%;
    animation: gradientShift 20s ease infinite;
    min-height: 100vh;
    overflow-x: hidden;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.header{
    position: fixed;
    top: 25px;
    left: 0;
    right: 0;
    display: flex;
    align-items: center;
    justify-content: center; /* căn giữa toàn bộ nội dung */
    z-index: 1000;
}

.navbar{
	margin-top: 30px;
    display: flex;
    gap: 2em;
    padding: 5px 25px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.25);
    box-shadow: 
        0 8px 32px rgba(12, 12, 16, 0.25),
        inset 0 1px 0 rgba(255, 255, 255, 0.3);
    position: absolute;
    left: 50%;
    transform: translateX(-50%); /* đảm bảo nav luôn ở giữa */
}

.navlink{
    color: rgba(255, 255, 255, 0.95);
    text-decoration: none;
    font-weight: 500;
    font-size: 1.1em;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.navlink::before{
    content: "";
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3));
    transition: left 0.5s;
}

.navlink:hover::before{ left: 100%; }

.navlink:hover{
    color: white;
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.auth-buttons{
	margin-top: 20px;
    position: absolute;
    right: 40px; /* cố định góc phải */
    display: flex;
    gap: 1em;
}
.btn{
    color: rgba(255, 255, 255, 0.95);
    text-decoration: none;
    font-weight: 500;
    font-size: 1em;
    padding: 0.6rem 1.2rem;
    border-radius: 25px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.25);
    transition: all 0.3s;
}

.btn:hover{
    color: white;
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

section{
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 45px;
    font-weight: 600;
    color: white;
}
li{
    list-style: none;
}
.fa-brands{
    font-size: 30px;
    color: #262626;
    line-height: 60px;
    transform: 0.5s;
}
a.Lienhe{
    position: relative;
    display: block;
    height: 60px;
   
    width: 60px;
    background: #fff;
    text-align: center;
    color: #fff;
    transform: perspective(1000px) rotate(-30deg) skew(25deg) translate(0 , 0);
    transition: 0.5s;
    transition-timing-function:linear ;
    box-shadow: -20px 20px 10px rgba(0, 0, 0, 0.5);
}
a.Lienhe:before{
    content:"";
    position: absolute;
    top: 10px;
    left: -20px;
    height: 100%;
    width: 20px;
    background: #b1b1b1;
    transition: 0.5s;
    transform: rotate(0deg) skewY(-45deg);
}
a.Lienhe:after{
    content: "";
    position: absolute;
    bottom: -20px;
    left: -10px;
    height: 20px;
    width: 100%;
     background: #b1b1b1;
    transition: 0.85s;
    transform: rotate(0deg) skewX(-45deg);
}
a.Lienhe:hover{
    transform: perspective(1000px) rotate(-30deg) skew(25deg) translate(20px, -20px);
    box-shadow: -50px 50px rgba(0, 0, 0, 0.5);
}
li:hover.fa-brands{
    color: #fff;
}
li:hover a.Lienhe{
    background: var(--clr0);
}
li:hover a.Lienhe:hover{
    background: var(--clr1);
}
li:hover a.Lienhe:after{
    background: var(--clr2);
}
.icon-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 80px;  
  flex-wrap: wrap;
  list-style: none;
  padding: 0;
  margin: 0;
}