:root {
    --koi-red: #202B7B;
    --koi-red-deep: #161D58;
    --koi-ink: #141A3B;
    --koi-ink-soft: #474E79;
    --koi-muted: #7A80A8;
    --koi-line: #DEE1F0;
    --koi-blush: #AEB6E4;
    --koi-blush-tint: #F6F7FC;
    --koi-shadow: 0 14px 40px rgba(43,18,20,.10);
}
.koi-header,
.koi-header button,
.koi-header input,
.koi-header a {
    font-family: 'Quicksand', system-ui, sans-serif;
}
.koi-header,
.koi-header * { box-sizing: border-box; }

.koi-header {
    position: sticky;
    top: 0;
    z-index: 1;
    height: 80px;
    background: rgba(255,255,255,.98);
    border-bottom: 1px solid var(--koi-line);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    transition: box-shadow .25s ease;
}

.koi-header.is-scrolled { box-shadow: 0 4px 18px rgba(43,18,20,.05); }

.koi-header__inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    padding-left: 40px;
    padding-right: 40px;
}

.koi-brand { flex: 0 0 auto; min-width: 68px; height:35px; }
.koi-brand .custom-logo-link,
.koi-brand__fallback {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 3px;
    text-align: center;
    text-decoration: none;
}
.koi-brand .custom-logo { width: 48px; height: 48px; object-fit: contain; }
.koi-brand__fallback strong {
    color: var(--koi-red);
    font-size: 9.5px;
    line-height: 1.1;
    letter-spacing: .05em;
    white-space: nowrap;
}
.koi-brand__mark {
    width: 44px;
    height: 44px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: linear-gradient(145deg,#E61E28,var(--koi-red));
    color: #fff;
    font-size: 12px;
    font-weight: 700;
}

.koi-navigation { margin-left: auto; }
.koi-menu,
.koi-menu ul { margin: 0; padding: 0; list-style: none; }
.koi-menu { display: flex; align-items: center; gap: 2px; }
.koi-menu > li { position: relative; }
.koi-menu a {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 8px 10px;
    border-radius: 8px;
    color: var(--koi-ink-soft);
    font-size: 13.5px;
    font-weight: 600;
    line-height: 1.4;
    text-decoration: none;
    transition: color .2s, background .2s;
    text-align: center;
}
.koi-menu > li > a:hover,
.koi-menu > li.current-menu-item > a,
.koi-menu > li.current-menu-ancestor > a {
    color: var(--koi-red);
    background: var(--koi-blush-tint);
}
.koi-menu .menu-item-has-children > a::after {
    content: '';
    width: 7px;
    height: 7px;
    margin-left: 2px;
    border-right: 1.5px solid currentColor;
    border-bottom: 1.5px solid currentColor;
    transform: rotate(45deg) translateY(-2px);
    opacity: .55;
    transition: transform .2s;
}
.koi-menu > .menu-item-has-children:hover > a::after { transform: rotate(225deg) translate(-1px,-1px); }

.koi-menu .sub-menu {
    position: absolute;
    top: calc(100% + 6px);
    left: 50%;
    z-index: 20;
    min-width: 220px;
    padding: 10px;
    background: #fff;
    border: 1px solid var(--koi-line);
    border-radius: 16px;
    box-shadow: var(--koi-shadow);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateX(-50%) translateY(6px);
    transition: .22s cubic-bezier(.22,1,.36,1);
    margin-top:-5px;
}
.koi-menu li:hover > .sub-menu,
.koi-menu li:focus-within > .sub-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}
.koi-menu .sub-menu a {
    display: block;
    padding: 10px 12px;
    font-weight: 500;
}
.koi-menu .sub-menu a:hover { color: var(--koi-red); background: var(--koi-blush); }

/* Gắn class CSS "koi-mega-menu" vào mục menu cha để có mega menu 3 cột. */
.koi-menu > li.koi-mega-menu > .sub-menu {
    left: 0;
    min-width: 620px;
    display: grid;
    grid-template-columns: repeat(2,minmax(0,1fr));
    gap: 12px;
    padding: 20px;
    transform: translateY(6px);
    margin-top: -5px;
}
.koi-menu > li.koi-mega-menu:hover > .sub-menu,
.koi-menu > li.koi-mega-menu:focus-within > .sub-menu { transform: translateY(0); }
.koi-menu > li.koi-mega-menu > .sub-menu > li > a {
    height: 100%;
    padding: 14px;
    border: 1px solid var(--koi-line);
    border-radius: 10px;
    color: var(--koi-red);
    font-weight: 700;
    text-align: left;
}

.koi-header-actions { display: flex; align-items: center; gap: 10px; flex: 0 0 auto; }
.koi-hotline {
    display: flex;
    align-items: center;
    gap: 7px;
    padding: 8px 12px;
    border-radius: 999px;
    color: var(--koi-red);
    font-size: 13.5px;
    font-weight: 600;
    text-decoration: none;
}
.koi-hotline:hover { background: var(--koi-blush); color: var(--koi-red); }
.koi-header-button {
    min-height: 42px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0 18px;
    border-radius: 999px;
    background: var(--koi-red);
    color: #fff;
    font-size: 13.5px;
    font-weight: 600;
    text-decoration: none;
    box-shadow: 0 4px 14px rgba(212,21,31,.22);
}
.koi-header-button:hover { background: var(--koi-red-deep); color: #fff; }
.koi-menu-toggle,
.koi-menu-close,
.koi-menu-overlay { display: none; }
.koi-mega-menu li{text-align: left}
.koi-mega-menu span {
    font-size: 12px;
    color: var(--muted);
    line-height: 1.45;
    font-weight: 500;
    display: block;
    margin-top:10px;
}
.koi-brand {
    flex: 0 0 auto;
    min-width: 100px;
}

.koi-brand__link {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    color: var(--koi-red);
    text-align: center;
    text-decoration: none;
}

.koi-brand__logo {
    width: auto !important;
    height: 38px !important;
}

.koi-brand__name {
    display: block;
    color: var(--koi-red);
    font-family: 'Quicksand', system-ui, sans-serif;
    font-size: 11px;
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: .04em;
    text-transform: uppercase;
    white-space: nowrap;
}

.koi-brand__link:hover,
.koi-brand__link:focus {
    color: var(--koi-red);
}

@media (max-width: 1100px) {
    .koi-header {
        position: sticky;
        top: 0;
        z-index: 2000;
        height: 76px;
        background: rgba(255,255,255,.98);
        backdrop-filter: none;
        -webkit-backdrop-filter: none;
        transform: none !important;
        filter: none !important;
        perspective: none !important;
        contain: none !important;
    }

    .koi-header__inner {
        height: 100%;
        padding-left: 22px;
        padding-right: 22px;
        gap: 12px;
    }

    .koi-brand .custom-logo {
        width: 38px;
        height: 38px;
    }

    .koi-header-actions {
        display: none;
    }

    .koi-menu-toggle {
        position: relative;
        z-index: 2100;
        width: 42px;
        height: 42px;
        min-width: 42px;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 4px;
        padding: 0;
        border: 1px solid #f0d9d7;
        border-radius: 12px;
            background: var(--blush-tint) !important;
        color: var(--koi-red);
        box-shadow: 0 4px 12px rgba(43,18,20,.05);
        cursor: pointer;
    }

    .koi-menu-toggle span {
        width: 18px;
        height: 2px;
        border-radius: 2px;
        background: currentColor;
    }

    .koi-navigation {
        position: fixed !important;
        top: 0 !important;
        right: 0 !important;
        bottom: auto !important;
        left: auto !important;
        z-index: 2200;
        width: min(88vw, 340px);
        height: 100vh;
        height: 100dvh;
        margin: 0;
        padding: 64px 14px 26px;
        background: #fff;
        overflow-x: hidden;
        overflow-y: auto;
        overscroll-behavior: contain;
        -webkit-overflow-scrolling: touch;
        box-shadow: -16px 0 48px rgba(10,37,64,.16);
        transform: translate3d(105%,0,0);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: transform .28s cubic-bezier(.22,1,.36,1), opacity .2s ease, visibility 0s linear .28s;
    }

    .koi-navigation.is-open {
        transform: translate3d(0,0,0);
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transition: transform .28s cubic-bezier(.22,1,.36,1), opacity .2s ease, visibility 0s;
    }

    .koi-menu-close {
        position: absolute;
        top: 12px;
        right: 14px;
        z-index: 2300;
        width: 40px;
        height: 40px;
        display: grid;
        place-items: center;
        padding: 0;
        border: 0;
        border-radius: 12px;
        background: var(--koi-blush);
        color: var(--koi-red);
        font-size: 28px;
        line-height: 1;
        cursor: pointer;
    }

    .koi-menu {
        display: block;
    }

    .koi-menu > li {
        width: fit-content;
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
        text-align: center;
    }

    .koi-menu > li > a {
        width: fit-content;
        min-height: 50px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        gap: 10px;
        padding: 12px 14px;
        font-size: 16px;
        white-space: nowrap;
    }

    .koi-menu .menu-item-has-children > a::after {
        display: inline-block;
        margin-left: 10px;
    }

    .menu-item-has-children span {
        display: none;
    }

    .koi-menu .sub-menu,
    .koi-menu > li.koi-mega-menu > .sub-menu {
        position: static;
        min-width: 0;
        display: none !important;
        grid-template-columns: 1fr;
        gap: 6px;
        padding: 0 0 10px;
        border: 0;
        border-radius: 0;
        box-shadow: none;
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transform: none !important;
    }

    .koi-menu li.submenu-open > .sub-menu {
        display: block !important;
    }

    .koi-menu > li.koi-mega-menu.submenu-open > .sub-menu {
        display: grid !important;
    }

    .koi-menu > li.koi-mega-menu > .sub-menu > li {
        width: fit-content;
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
        border-bottom: 1px solid #eadedc;
        border-radius: 0 0 12px 12px;
        box-shadow: none;
    }

    .koi-menu .sub-menu > li {
        width: fit-content;
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
    }

    .koi-menu .sub-menu a,
    .koi-menu > li.koi-mega-menu > .sub-menu > li > a {
        width: fit-content;
        min-height: 44px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        padding: 10px 14px;
        border: 0;
        border-radius: 10px;
        color: var(--koi-ink-soft);
        font-size: 14px;
        font-weight: 600;
    }

    .koi-menu-overlay {
        position: fixed !important;
        inset: 0 !important;
        z-index: 1900;
        display: block;
        width: 100vw;
        height: 100vh;
        height: 100dvh;
        margin: 0;
        padding: 0;
        background: rgba(43,18,20,.38);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: opacity .25s ease, visibility .25s ease;
    }

    .koi-menu-overlay.is-open {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
    }

    .koi-navigation,
    .koi-navigation .koi-menu,
    .koi-navigation .koi-menu li,
    .koi-navigation .koi-menu a,
    .koi-menu-close {
        pointer-events: auto;
    }

    html.koi-menu-open {
        overflow: hidden;
    }

    html.koi-no-smooth-scroll {
        scroll-behavior: auto !important;
    }
}

@media (max-width: 480px) {
    .koi-header__inner { padding-left: 16px; padding-right: 16px; }
}