/* ── Heatlyt · shared stylesheet ── */

:root {
    --green:      #7cbd2a;
    --green-dark: #639a21;
    --black:      #151515;
    --grey-light: #f4f6f8;
    --grey-text:  #666666;
    --border:     #e1e4e8;
    --white:      #ffffff;
}

/* ── RESET ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: var(--black);
    background: var(--white);
    line-height: 1.6;
    font-size: 15px;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
ul { list-style: none; padding: 0; }

/* ── HEADER & NAV ── */
header {
    position: sticky;
    top: 0;
    z-index: 200;
    background: var(--black);
    border-bottom: 2px solid var(--green);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 32px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo { display: flex; align-items: center; gap: 10px; }
.logo img { height: 30px; width: auto; }

.nav-links { display: flex; gap: 4px; }

.nav-links a {
    padding: 7px 15px;
    color: rgba(255,255,255,.8);
    font-size: .875rem;
    font-weight: 500;
    border-radius: 3px;
    transition: color .15s, background .15s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--white);
    background: rgba(124,189,42,.2);
}

.nav-cta {
    background: var(--green) !important;
    color: var(--black) !important;
    font-weight: 700 !important;
}

.nav-cta:hover {
    background: var(--green-dark) !important;
    color: var(--white) !important;
}

.burger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
}

.burger span {
    width: 22px;
    height: 2px;
    background: var(--white);
    border-radius: 2px;
    transition: .3s;
}

/* ── BREADCRUMB ── */
.breadcrumb {
    background: var(--grey-light);
    padding: 12px 32px;
    font-size: .8rem;
    color: var(--grey-text);
}
.breadcrumb a { color: var(--green-dark); }
.breadcrumb a:hover { color: var(--green); }

/* ── BUTTONS ── */
.btn {
    display: inline-block;
    padding: 11px 24px;
    font-size: .875rem;
    font-weight: 700;
    border-radius: 3px;
    transition: .15s;
    cursor: pointer;
}

.btn-green { background: var(--green); color: var(--black); }
.btn-green:hover { background: var(--green-dark); color: var(--white); }

.btn-outline { border: 2px solid var(--border); color: var(--black); }
.btn-outline:hover { border-color: var(--green); color: var(--green-dark); }

.btn-outline-white {
    background: transparent;
    color: var(--white);
    border: 2px solid rgba(255,255,255,.6);
}
.btn-outline-white:hover { border-color: var(--white); background: rgba(255,255,255,.1); }

/* ── LAYOUT HELPERS ── */
section { padding: 72px 32px; }
.container { max-width: 1200px; margin: 0 auto; }

.section-label {
    font-size: .75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: var(--green-dark);
    margin-bottom: 8px;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 36px;
    letter-spacing: -.3px;
}

/* ── INDEX · HERO ── */
.hero {
    position: relative;
    min-height: 480px;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: url('images/header_dhw.jpg') center center / cover no-repeat;
}

.hero-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(0,0,0,.75) 0%, rgba(0,0,0,.4) 60%, transparent 100%);
}

.hero-content {
    position: relative;
    z-index: 10;
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 32px;
    color: var(--white);
}

.hero-eyebrow {
    display: inline-block;
    background: var(--green);
    color: var(--black);
    font-size: .75rem;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    padding: 5px 12px;
    border-radius: 3px;
    margin-bottom: 20px;
}

.hero-content h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    line-height: 1.15;
    max-width: 580px;
    margin-bottom: 18px;
    letter-spacing: -.5px;
}

.hero-content p {
    font-size: 1.05rem;
    opacity: .88;
    max-width: 500px;
    margin-bottom: 32px;
    font-weight: 300;
    line-height: 1.65;
}

.hero-btns { display: flex; gap: 12px; flex-wrap: wrap; }

/* ── INDEX · SECTION HEADER ── */
.section-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    margin-bottom: 40px;
    gap: 20px;
    flex-wrap: wrap;
}

.section-header h2 {
    font-size: 1.75rem;
    font-weight: 800;
    letter-spacing: -.3px;
}

.section-header h2 span { color: var(--green); }

.section-header a {
    font-size: .875rem;
    font-weight: 700;
    color: var(--green-dark);
    white-space: nowrap;
}

.section-header a:hover { color: var(--green); }

/* ── INDEX · SERIES TABS ── */
.series-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 32px;
    flex-wrap: wrap;
}

.tab {
    padding: 8px 20px;
    border: 2px solid var(--border);
    border-radius: 30px;
    font-size: .85rem;
    font-weight: 600;
    color: var(--grey-text);
    cursor: pointer;
    transition: .15s;
    background: var(--white);
}

.tab.active, .tab:hover {
    border-color: var(--green);
    color: var(--black);
    background: rgba(124,189,42,.08);
}

/* ── INDEX · PRODUCT GRID ── */
.product-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.product-card {
    border: 1px solid var(--border);
    border-radius: 6px;
    overflow: hidden;
    background: var(--white);
    transition: box-shadow .2s, transform .2s;
    display: flex;
    flex-direction: column;
}

.product-card:hover {
    box-shadow: 0 8px 30px rgba(0,0,0,.1);
    transform: translateY(-3px);
}

.product-card-img {
    background: var(--grey-light);
    padding: 32px 20px 16px;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    min-height: 180px;
    position: relative;
}

.product-card-img img {
    height: 160px;
    width: auto;
    object-fit: contain;
    filter: drop-shadow(0 10px 20px rgba(0,0,0,.12));
}

.product-series-tag {
    position: absolute;
    top: 12px;
    left: 12px;
    background: var(--black);
    color: var(--white);
    font-size: .65rem;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    padding: 4px 9px;
    border-radius: 3px;
}

.product-series-tag.buffer { background: #2a5a8c; }
.product-series-tag.dhw    { background: #8c2a2a; }
.product-series-tag.duo    { background: #5a2a8c; }

.product-card-body {
    padding: 16px 18px 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.product-card-body h3 { font-size: 1.05rem; font-weight: 800; margin-bottom: 3px; }
.card-title-link { display: block; text-decoration: none; color: inherit; }
.card-title-link:hover h3 { color: var(--green); }

.product-card-body .subtitle {
    font-size: .78rem;
    color: var(--green-dark);
    font-weight: 600;
    margin-bottom: 10px;
}

.product-card-body p {
    font-size: .82rem;
    color: var(--grey-text);
    line-height: 1.5;
    flex: 1;
}

.product-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
}

.spec-pill { font-size: .75rem; font-weight: 600; color: var(--grey-text); }

.card-link { font-size: .8rem; font-weight: 700; color: var(--green-dark); }
.card-link:hover { color: var(--green); }
.card-link::after { content: " →"; }

/* ── INDEX · WHY US ── */
.why-us { background: var(--black); color: var(--white); }

.why-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
}

.why-icon {
    width: 44px; height: 44px;
    background: rgba(124,189,42,.15);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 14px;
    color: var(--green);
}

.why-item h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.why-item p  { font-size: .85rem; color: rgba(255,255,255,.6); line-height: 1.6; }

/* ── INDEX · ABOUT ── */
.about-inner {
    display: grid;
    grid-template-columns: 55% 1fr;
    gap: 64px;
    align-items: center;
}

.about-text h2 {
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 20px;
    letter-spacing: -.3px;
}

.about-text h2 span { color: var(--green); }

.about-text p {
    color: var(--grey-text);
    font-size: .9rem;
    line-height: 1.7;
    margin-bottom: 14px;
}

.about-facts {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-top: 28px;
}

.fact {
    background: var(--grey-light);
    padding: 18px;
    border-radius: 5px;
    border-left: 3px solid var(--green);
}

.fact-value {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--black);
    line-height: 1;
    margin-bottom: 4px;
}

.fact-label { font-size: .78rem; color: var(--grey-text); }

.about-visual { position: relative; }

.about-visual img.header-img {
    width: 100%;
    border-radius: 6px;
    object-fit: cover;
    aspect-ratio: 4/3;
}

.about-visual img.tank-float {
    position: absolute;
    bottom: -20px;
    right: -20px;
    height: 160px;
    width: auto;
    filter: drop-shadow(0 15px 25px rgba(0,0,0,.2));
}

/* ── INDEX · FAQ ── */
.faq-section { background: var(--grey-light); }
.faq-accordion {
    max-width: 860px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 14px;
}
.faq-accordion details {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 6px;
    overflow: hidden;
    transition: box-shadow .2s, border-color .2s;
}
.faq-accordion details[open] {
    border-color: var(--green);
    box-shadow: 0 4px 20px rgba(0,0,0,.06);
}
.faq-accordion summary {
    padding: 22px 28px;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--black);
    cursor: pointer;
    list-style: none; /* Remove default marker */
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    transition: color .2s;
}
.faq-accordion summary::-webkit-details-marker { display: none; } /* Safari/Chrome hide marker */
.faq-accordion summary:hover { color: var(--green-dark); }
.faq-accordion summary::after {
    content: '+';
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--green);
    line-height: 1;
    transition: transform .2s ease-in-out;
}
.faq-accordion details[open] summary::after {
    content: '−';
    transform: rotate(180deg);
}
.faq-accordion details[open] summary {
    border-bottom: 1px solid var(--border);
    color: var(--green-dark);
}
.faq-accordion .faq-content {
    padding: 24px 28px;
    font-size: .95rem;
    color: var(--grey-text);
    line-height: 1.65;
    background: var(--white);
}

/* ── INDEX · CONTACT ── */
.contact { background: var(--grey-light); }

.contact-inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.contact-info h2 { font-size: 1.75rem; font-weight: 800; margin-bottom: 10px; }
.contact-info > p { color: var(--grey-text); font-size: .9rem; margin-bottom: 32px; }

.contact-row {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
    align-items: flex-start;
}

.contact-icon {
    width: 38px; height: 38px;
    background: var(--green);
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.contact-icon svg { stroke: var(--black); }

.contact-row h4 {
    font-size: .75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--grey-text);
    margin-bottom: 3px;
}

.contact-row p, .contact-row a { font-size: .9rem; color: var(--black); }
.contact-row a:hover { color: var(--green-dark); }

.contact-form {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 36px 32px;
}

.contact-form h3 { font-size: 1.1rem; font-weight: 800; margin-bottom: 22px; }

.form-group { margin-bottom: 14px; }

.form-group label {
    display: block;
    font-size: .8rem;
    font-weight: 600;
    color: var(--grey-text);
    margin-bottom: 5px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 9px 13px;
    border: 1px solid var(--border);
    border-radius: 3px;
    font-family: inherit;
    font-size: .875rem;
    color: var(--black);
    background: var(--white);
    transition: border-color .15s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus { outline: none; border-color: var(--green); }

.form-group textarea { min-height: 90px; resize: vertical; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }

.btn-submit {
    width: 100%;
    padding: 12px;
    background: var(--green);
    color: var(--black);
    border: none;
    border-radius: 3px;
    font-family: inherit;
    font-size: .9rem;
    font-weight: 700;
    cursor: pointer;
    margin-top: 6px;
    transition: background .15s;
}

.btn-submit:hover { background: var(--green-dark); color: var(--white); }

/* ── PRODUCT PAGES · HERO ── */
.product-hero {
    max-width: 1200px;
    margin: 0 auto;
    padding: 52px 32px;
    display: grid;
    grid-template-columns: 55% 1fr;
    gap: 64px;
    align-items: center;
}

.series-badge {
    display: inline-block;
    color: var(--white);
    font-size: .7rem;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    padding: 5px 11px;
    border-radius: 3px;
    margin-bottom: 16px;
}

.series-badge.buffer { background: #2a5a8c; }
.series-badge.dhw    { background: #8c2a2a; }
.series-badge.duo    { background: #5a2a8c; }

.hero-left h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1;
    letter-spacing: -1px;
    margin-bottom: 6px;
}

.hero-left .subtitle {
    font-size: 1.05rem;
    color: var(--green-dark);
    font-weight: 600;
    margin-bottom: 20px;
}

.hero-left .desc {
    font-size: .92rem;
    color: var(--grey-text);
    line-height: 1.7;
    margin-bottom: 24px;
}

.oem {
    border-left: 3px solid var(--green);
    padding-left: 14px;
    margin-bottom: 28px;
}

.oem h4 {
    font-size: .75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-bottom: 4px;
}

.oem p { font-size: .82rem; color: var(--grey-text); line-height: 1.5; }

.hero-right {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 32px 0;
}

.hero-right img {
    height: 340px;
    width: auto;
    filter: drop-shadow(0 20px 35px rgba(0,0,0,.15));
}

/* ── PRODUCT PAGES · FEATURES ── */
.features-section { background: var(--grey-light); padding: 56px 32px; }
.features-section .container { max-width: 1200px; margin: 0 auto; }

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 24px;
    border-top: 3px solid var(--green);
}

.f-icon {
    width: 40px; height: 40px;
    background: var(--grey-light);
    border-radius: 7px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--green-dark);
    margin-bottom: 14px;
}

.feature-card h3 { font-size: .95rem; font-weight: 700; margin-bottom: 8px; }
.feature-card p, .feature-card li { font-size: .82rem; color: var(--grey-text); line-height: 1.55; }

/* ── PRODUCT PAGES · SPECS ── */
.specs-section { padding: 56px 32px; }
.specs-section .container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.drawing-box { border: 1px solid var(--border); border-radius: 6px; padding: 20px; }
.drawing-box .label {
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: #bbb;
    margin-bottom: 12px;
}

.spec-table { width: 100%; border-collapse: collapse; font-size: .875rem; margin-bottom: 28px; }
.spec-table th {
    text-align: left;
    padding: 11px 14px;
    background: var(--black);
    color: var(--white);
    font-weight: 600;
    font-size: .8rem;
}
.spec-table td { padding: 11px 14px; border-bottom: 1px solid var(--border); color: #333; }
.spec-table tr:nth-child(even) td { background: var(--grey-light); }
.spec-table tr:last-child td { border-bottom: none; }

.warranty {
    background: var(--grey-light);
    border-left: 3px solid var(--black);
    border-radius: 4px;
    padding: 14px 16px;
    font-size: .8rem;
    color: var(--grey-text);
    line-height: 1.5;
}

.erp-wrap { margin-top: 24px; }
.erp-wrap h4 {
    font-size: .8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-bottom: 10px;
    color: var(--grey-text);
}
.erp-wrap img { max-width: 140px; border: 1px solid var(--border); border-radius: 5px; padding: 6px; }

/* ── PRODUCT PAGES · CTA STRIP ── */
.cta-strip { background: var(--black); padding: 48px 32px; text-align: center; color: var(--white); }
.cta-strip h2 { font-size: 1.5rem; font-weight: 800; margin-bottom: 10px; }
.cta-strip p { font-size: .9rem; color: rgba(255,255,255,.65); margin-bottom: 24px; }
.cta-strip .btn { padding: 13px 28px; font-size: .9rem; }

/* ── FOOTER ── */
footer {
    background: var(--black);
    color: rgba(255,255,255,.6);
    padding: 52px 32px 28px;
}

.footer-top {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2.5fr 1fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,.08);
}

.footer-brand img { height: 28px; margin-bottom: 14px; }
.footer-brand p { font-size: .83rem; line-height: 1.65; max-width: 280px; }

.footer-col h4 {
    color: var(--white);
    font-size: .85rem;
    font-weight: 700;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: .06em;
}

.footer-col li { margin-bottom: 9px; }
.footer-col a { font-size: .83rem; color: rgba(255,255,255,.55); transition: color .15s; }
.footer-col a:hover { color: var(--green); }

.footer-bottom {
    max-width: 1200px;
    margin: 24px auto 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: .78rem;
    flex-wrap: wrap;
    gap: 8px;
}

/* product pages use a simpler footer */
.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 10px;
    font-size: .78rem;
}

.footer-inner a { color: rgba(255,255,255,.5); }
.footer-inner a:hover { color: var(--green); }

/* ── RESPONSIVE ── */
@media (max-width: 1024px) {
    .product-grid { grid-template-columns: repeat(2, 1fr); }
    .why-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 60px; left: 0; right: 0;
        background: var(--black);
        padding: 12px 20px 20px;
        border-top: 1px solid rgba(255,255,255,.1);
    }
    .nav-links.open { display: flex; }
    .burger { display: flex; }
    .about-inner, .contact-inner { grid-template-columns: 1fr; gap: 36px; }
    .about-visual img.tank-float { display: none; }
    .footer-top { grid-template-columns: 1fr 1fr; gap: 28px; }
    .footer-bottom { flex-direction: column; text-align: center; }
    section { padding: 52px 20px; }
    .product-hero { grid-template-columns: 1fr; gap: 32px; }
    .hero-right img { height: 240px; }
    .features-grid { grid-template-columns: 1fr 1fr; }
    .specs-section .container { grid-template-columns: 1fr; gap: 36px; }
}

@media (max-width: 540px) {
    .product-grid { grid-template-columns: 1fr 1fr; }
    .why-grid { grid-template-columns: 1fr 1fr; }
    .form-row { grid-template-columns: 1fr; }
    .footer-top { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .features-grid { grid-template-columns: 1fr; }
}

@media (max-width: 360px) {
    .product-grid { grid-template-columns: 1fr; }
}