:root{
    --nen-hong: #ffe6ea;
    --hong-dam: #ff4d6d;
    --chu-chinh: #1a1a1a;
    --chu-phu: rgba(26, 26, 26, .65);
    --vien-kinh: rgba(255,255,255,.6);
    --nen-kinh: rgba(255,255,255,.55);
    --bong-kinh: 0 18px 60px rgba(255, 77, 109, .18);
}
html, body{
    height: 100%;
}
body{
    font-family: 'Poppins', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
    background: radial-gradient(1000px 700px at 15% 10%, rgba(255, 77, 109, .20), rgba(255, 230, 234, 0) 60%),
                radial-gradient(900px 650px at 85% 35%, rgba(255, 77, 109, .12), rgba(255, 230, 234, 0) 55%),
                var(--nen-hong);
    color: var(--chu-chinh);
}
a{
    text-decoration: none;
}
.khung-trang{
    min-height: 100vh;
}
.nen-kinh{
    background: var(--nen-kinh);
    border: 1px solid var(--vien-kinh);
    box-shadow: var(--bong-kinh);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
}
.khung-nho{
    border-radius: 18px;
}
.khung-lon{
    border-radius: 22px;
}
.chu-phu{
    color: var(--chu-phu);
}
.nut-hong{
    background: linear-gradient(135deg, #ff4d6d, #ff7a90);
    border: 0;
    color: #fff;
    box-shadow: 0 10px 25px rgba(255, 77, 109, .28);
}
.nut-hong:hover{
    filter: brightness(0.98);
    color: #fff;
}
.vien-hong{
    border-color: rgba(255, 77, 109, .40) !important;
}
.tieu-de-muc{
    font-weight: 700;
    letter-spacing: .2px;
}
.so-muc{
    width: 28px;
    height: 28px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    background: rgba(255, 77, 109, .15);
    color: var(--hong-dam);
    font-weight: 700;
    font-size: 12px;
}
.nav-kinh{
    border-radius: 18px;
}
.thanh-dieu-huong{
    position: sticky;
    top: 14px;
    z-index: 1020;
}
.thanh-dieu-huong.nen-kinh{
    background: linear-gradient(180deg, rgba(255,255,255,.72), rgba(255,255,255,.50));
    box-shadow: 0 18px 60px rgba(255, 77, 109, .16), 0 10px 22px rgba(0, 0, 0, .06);
}
.thuong-hieu{
    color: var(--chu-chinh);
    font-weight: 800;
    letter-spacing: .9px;
}
.thuong-hieu:hover{
    color: var(--chu-chinh);
}
.cham-logo{
    width: 10px;
    height: 10px;
    border-radius: 999px;
    background: linear-gradient(135deg, #ff4d6d, #ff8aa0);
    box-shadow: 0 10px 18px rgba(255, 77, 109, .35);
}
.nav-link{
    color: rgba(26, 26, 26, .70);
    font-weight: 500;
}
.nav-link:hover{
    color: rgba(26, 26, 26, .95);
}
.nav-pill{
    border-radius: 999px;
    padding: .55rem 1rem;
    transition: background-color .15s ease, color .15s ease, transform .15s ease;
}
.nav-pill:hover{
    background: rgba(255, 255, 255, .70);
    transform: translateY(-1px);
}
.nav-pill:focus-visible{
    outline: 3px solid rgba(255, 77, 109, .25);
    outline-offset: 2px;
}
.nut-icon{
    width: 44px;
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    background: rgba(255, 255, 255, .70);
    border: 1px solid var(--vien-kinh);
}
.nut-icon:hover{
    background: rgba(255, 255, 255, .78);
}
.avatar{
    width: 46px;
    height: 46px;
    border-radius: 14px;
    object-fit: cover;
}
.chip-nho{
    font-size: 11px;
    font-weight: 600;
    letter-spacing: .4px;
    color: var(--hong-dam);
}
.tieu-de-lon{
    font-weight: 800;
    letter-spacing: .6px;
    line-height: 1.08;
}
.the-ky-nang{
    border-radius: 18px;
    padding: 22px;
    height: 100%;
}
.vung-hoc{
    border-radius: 22px;
    overflow: hidden;
}
.vung-hoc-ben-phai{
    background: linear-gradient(135deg, #ff2d55, #ff6b6b);
    min-height: 260px;
    position: relative;
}
.vung-hoc-chu{
    color: rgba(255,255,255,.85);
    font-weight: 700;
    letter-spacing: .6px;
    font-size: 56px;
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: rotate(-12deg);
    opacity: .25;
}
.tieu-de-footer{
    font-weight: 700;
    letter-spacing: .2px;
    margin-bottom: .75rem;
}
.link-footer{
    color: rgba(26, 26, 26, .72);
    font-weight: 500;
    display: inline-flex;
    gap: .6rem;
    align-items: center;
    padding: .28rem 0;
    transition: color .15s ease, transform .15s ease;
}
.link-footer:hover{
    color: rgba(26, 26, 26, .95);
    transform: translateX(2px);
}
.icon-footer{
    width: 38px;
    height: 38px;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, .70);
    border: 1px solid var(--vien-kinh);
}
.icon-footer:hover{
    background: rgba(255, 255, 255, .80);
}
.o-nhap-footer{
    background: rgba(255,255,255,.75);
    border: 1px solid var(--vien-kinh);
    border-radius: 999px;
}
.o-nhap-footer:focus{
    box-shadow: 0 0 0 .25rem rgba(255, 77, 109, .18);
    border-color: rgba(255, 77, 109, .35);
}
.dang-ky-footer{
    border-radius: 999px;
    overflow: hidden;
    border: 1px solid var(--vien-kinh);
    background: rgba(255,255,255,.68);
    box-shadow: 0 14px 35px rgba(255, 77, 109, .10);
}
.dang-ky-footer .form-control{
    border: 0;
    background: transparent;
    padding: .85rem 1rem;
}
.dang-ky-footer .form-control::placeholder{
    color: rgba(26, 26, 26, .55);
}
.dang-ky-footer .form-control:focus{
    box-shadow: none;
}
.nut-gui-footer{
    border: 0;
    border-radius: 0;
    padding: .85rem 1rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 52px;
}