/* ===== OperoSense brand ===== */
:root {
    --navy: #0d1b2a;
    --navy-2: #0a1622;
    --blue: #2f83c2;        /* decorative only: borders, icons (4.1:1 on white) */
    --blue-deep: #1f6fb2;   /* text and buttons on white (5.3:1) */
    --lime: #a8ce3a;        /* on dark backgrounds only */
    --lime-text: #4d7c0f;   /* lime for text on white (5.0:1) */
    --light: #f6f8fb;
    --gray: #e2e8f0;
    --text-main: #334155;
    --text-muted: #55647a;
    --font-stack: 'Inter', system-ui, -apple-system, sans-serif;
}

/* ---- multi-language display logic ---- */
[data-lang="en"] .lang-vi, [data-lang="en"] .lang-no { display: none; }
[data-lang="vi"] .lang-en, [data-lang="vi"] .lang-no { display: none; }
[data-lang="no"] .lang-en, [data-lang="no"] .lang-vi { display: none; }
[data-lang="en"] .input-vi, [data-lang="en"] .input-no { display: none; }
[data-lang="vi"] .input-en, [data-lang="vi"] .input-no { display: none; }
[data-lang="no"] .input-en, [data-lang="no"] .input-vi { display: none; }

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body { font-family: var(--font-stack); color: var(--text-main); line-height: 1.65; }
.container { max-width: 1140px; margin: 0 auto; padding: 0 22px; }
img { max-width: 100%; height: auto; display: block; }

/* ---- accessibility helpers ---- */
:focus-visible { outline: 3px solid var(--blue-deep); outline-offset: 3px; border-radius: 4px; }
.section-dark :focus-visible, .hero :focus-visible, footer :focus-visible { outline-color: var(--lime); }
.skip-link { position: absolute; left: 12px; top: -60px; background: var(--navy); color: #fff; padding: 10px 16px; border-radius: 6px; z-index: 2000; font-weight: 600; text-decoration: none; }
.skip-link:focus { top: 12px; }

/* ---- header & nav ---- */
header { background: #fff; position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 14px rgba(13,27,42,0.07); }
nav { display: flex; justify-content: space-between; align-items: center; padding: 14px 5%; max-width: 1300px; margin: 0 auto; }
.brand { display: flex; align-items: center; gap: 11px; text-decoration: none; }
.brand-mark { width: 38px; height: 38px; }
.brand-name { font-size: 1.5rem; font-weight: 800; color: var(--blue-deep); letter-spacing: -.3px; }
.brand-accent { color: var(--lime-text); }
.nav-links { list-style: none; display: flex; gap: 26px; align-items: center; }
.nav-links a { text-decoration: none; color: var(--navy); font-weight: 600; font-size: 0.95rem; transition: color .2s; }
.nav-links a:hover { color: var(--blue-deep); }
.btn-nav { background: var(--blue-deep); color: #fff !important; padding: 9px 18px; border-radius: 6px; }
.btn-nav:hover { background: var(--navy); }
.lang-switch select { width: auto; padding: 6px 8px; border-radius: 6px; border: 1px solid #cbd5e1; cursor: pointer; font-weight: 600; font-size: 0.95rem; color: var(--navy); background: #fff; }
.nav-toggle { display: none; background: none; border: 1px solid #cbd5e1; border-radius: 8px; width: 44px; height: 44px; cursor: pointer; color: var(--navy); align-items: center; justify-content: center; }

/* ---- hero ---- */
.hero {
    background:
        radial-gradient(900px 400px at 85% 0%, rgba(47,131,194,0.28), transparent 70%),
        radial-gradient(700px 360px at 5% 100%, rgba(168,206,58,0.12), transparent 70%),
        linear-gradient(180deg, #091421, #0d1b2a);
    color: #fff; padding: 112px 20px 100px; text-align: center;
}
.hero-wrapper { max-width: 880px; margin: 0 auto; }
.eyebrow { display: inline-block; color: var(--lime); font-weight: 600; font-size: 0.9rem; letter-spacing: 1.5px; text-transform: uppercase; margin-bottom: 20px; border: 1px solid rgba(168,206,58,.35); padding: 6px 16px; border-radius: 40px; }
.hero h1 { font-size: 3.3rem; margin-bottom: 22px; line-height: 1.15; font-weight: 800; letter-spacing: -1px; }
.hero p { font-size: 1.2rem; color: #cbd5e1; margin-bottom: 38px; max-width: 720px; margin-inline: auto; }
.cta-group { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ---- sections ---- */
.section-light { padding: 96px 0; background: #fff; }
.section-gray { padding: 96px 0; background: var(--light); }
.section-dark { padding: 96px 0; background: var(--navy); color: #fff; }
.section-title { font-size: 2.4rem; text-align: center; margin-bottom: 14px; color: var(--navy); font-weight: 800; letter-spacing: -.5px; line-height: 1.2; }
.section-dark .section-title { color: #fff; }
.section-subtitle { text-align: center; color: var(--text-muted); margin-bottom: 54px; max-width: 720px; margin-inline: auto; }
.section-dark .section-subtitle { color: #b4c4d4; }

/* ---- service cards ---- */
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 24px; }
.card { padding: 32px 28px; border: 1px solid var(--gray); border-radius: 14px; background: #fff; transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease; }
.card:hover { transform: translateY(-6px); border-color: var(--blue); box-shadow: 0 18px 38px rgba(13,27,42,0.09); }
.card-icon { width: 48px; height: 48px; border-radius: 12px; background: rgba(47,131,194,0.10); color: var(--blue-deep); display: flex; align-items: center; justify-content: center; margin-bottom: 18px; }
.card-icon svg { width: 26px; height: 26px; }
.card h3 { color: var(--navy); margin-bottom: 10px; font-size: 1.15rem; line-height: 1.3; }
.card p { font-size: 0.97rem; }

/* ---- how we work ---- */
.steps { list-style: none; display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 24px; counter-reset: step; }
.steps li { counter-increment: step; position: relative; padding: 24px 22px 22px; background: var(--light); border-radius: 14px; border: 1px solid var(--gray); }
.steps li::before { content: counter(step); display: flex; align-items: center; justify-content: center; width: 34px; height: 34px; border-radius: 50%; background: var(--navy); color: var(--lime); font-weight: 800; margin-bottom: 14px; }
.steps strong { display: block; color: var(--navy); font-size: 1.05rem; margin-bottom: 4px; }
.steps p { font-size: 0.95rem; color: var(--text-muted); }
.steps-note { text-align: center; margin-top: 28px; color: var(--text-muted); font-size: 0.95rem; }

/* ---- platform / figure ---- */
.product-layout { display: grid; grid-template-columns: 1.1fr 1fr; gap: 54px; align-items: center; }
.product-figure img { border-radius: 14px; border: 1px solid var(--gray); box-shadow: 0 18px 40px rgba(13,27,42,0.10); }
.figure-caption { display: block; margin-top: 14px; font-size: 0.85rem; color: var(--text-muted); font-style: italic; }
.product-copy h3 { color: var(--navy); font-size: 1.5rem; line-height: 1.3; margin-bottom: 12px; }
.product-copy p { margin-bottom: 14px; }
.product-note { padding: 16px 18px; background: var(--light); border-radius: 10px; font-size: 0.92rem; color: var(--text-muted); }

/* ---- coverage spec sheet ---- */
.coverage { margin-top: 56px; border: 1px solid var(--gray); border-radius: 16px; background: #fff; overflow: hidden; box-shadow: 0 8px 26px rgba(13,27,42,0.06); }
.coverage-title { display: block; background: var(--navy); color: #fff; font-weight: 700; font-size: 0.95rem; letter-spacing: .4px; padding: 15px 28px; }
.coverage-row { display: grid; grid-template-columns: 210px 1fr; gap: 22px; align-items: center; padding: 20px 28px; border-top: 1px solid var(--gray); }
.coverage-label { font-weight: 700; color: var(--navy); font-size: 1rem; }
.coverage-tags { display: flex; flex-wrap: wrap; gap: 10px; }
.coverage-tags > span { background: var(--light); border: 1px solid var(--gray); color: var(--navy); font-weight: 600; font-size: 0.88rem; padding: 8px 15px; border-radius: 8px; }

/* ---- team ---- */
.team { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 28px; max-width: 900px; margin: 0 auto; }
.founder { background: #fff; border: 1px solid var(--gray); border-radius: 14px; padding: 30px 28px 26px; text-align: center; display: flex; flex-direction: column; align-items: center; gap: 5px; box-shadow: 0 8px 24px rgba(13,27,42,0.05); }
.founder-photo { width: 104px; height: 104px; border-radius: 50%; object-fit: cover; border: 3px solid var(--blue); margin-bottom: 8px; background: var(--gray); }
.founder-name { font-weight: 800; color: var(--navy); font-size: 1.2rem; }
.founder-role { color: var(--blue-deep); font-weight: 700; font-size: 0.92rem; margin-bottom: 6px; }
.founder-bio { font-size: 0.95rem; color: var(--text-main); margin-bottom: 12px; }
.founder-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; }
.founder-links a { font-size: 0.82rem; font-weight: 600; color: var(--blue-deep); text-decoration: none; border: 1px solid #cbd5e1; padding: 8px 12px; border-radius: 40px; transition: .2s; }
.founder-links a:hover { background: var(--blue-deep); color: #fff; border-color: var(--blue-deep); }
.team-note { text-align: center; margin-top: 28px; color: var(--text-muted); font-size: 0.9rem; }

/* ---- research papers ---- */
.paper { display: grid; grid-template-columns: 1fr 1.2fr; gap: 44px; align-items: center; background: rgba(255,255,255,0.04); border: 1px solid rgba(255,255,255,0.09); border-radius: 16px; padding: 30px; margin-bottom: 34px; }
.paper.reverse { grid-template-columns: 1.2fr 1fr; }
.paper.reverse .paper-figure { order: 2; }
.paper.no-figure { grid-template-columns: 1fr; }
.paper-figure img { border-radius: 12px; background: #fff; padding: 8px; }
.paper-journal { color: var(--lime); font-weight: 600; font-size: 0.82rem; letter-spacing: .5px; text-transform: uppercase; }
.paper-body h3 { color: #fff; font-size: 1.4rem; margin: 10px 0 14px; line-height: 1.3; }
.paper-body p { color: #c9d6e2; margin-bottom: 14px; }
.paper-body .paper-authors { font-size: 0.85rem; color: #a3b5c6; font-style: italic; }
.btn-outline { border: 2px solid var(--lime); color: var(--lime); background: transparent; padding: 11px 22px; }
.btn-outline:hover { background: var(--lime); color: var(--navy); }

/* ---- coming soon card ---- */
.coming-soon { text-align: center; border: 2px dashed rgba(168,206,58,0.45); border-radius: 16px; padding: 34px 28px; background: rgba(255,255,255,0.03); }
.badge-review { display: inline-block; background: rgba(168,206,58,0.15); color: var(--lime); border: 1px solid rgba(168,206,58,0.5); font-size: 0.75rem; font-weight: 700; letter-spacing: .8px; text-transform: uppercase; padding: 5px 14px; border-radius: 40px; margin-bottom: 14px; }
.coming-soon h3 { color: #fff; font-size: 1.4rem; margin-bottom: 12px; }
.coming-soon p { color: #c9d6e2; max-width: 680px; margin: 0 auto; }

/* ---- form ---- */
.form-container { max-width: 820px; }
.inquiry-form { background: #fff; padding: 40px; border-radius: 14px; box-shadow: 0 12px 34px rgba(13,27,42,0.07); }
.form-row { display: flex; gap: 20px; margin-bottom: 20px; }
.input-group { flex: 1; margin-bottom: 0; }
.inquiry-form > .input-group { margin-bottom: 20px; }
.inquiry-form label { display: block; font-weight: 600; font-size: 0.9rem; color: var(--navy); margin-bottom: 6px; }
input, select, textarea { width: 100%; padding: 14px; border: 1px solid #94a3b8; border-radius: 8px; font-size: 1rem; font-family: inherit; color: var(--navy); background: #fff; transition: border-color .25s, box-shadow .25s; }
input::placeholder, textarea::placeholder { color: #64748b; }
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--blue-deep); box-shadow: 0 0 0 3px rgba(31,111,178,0.25); }
textarea { resize: vertical; }
.hp { position: absolute; left: -9999px; height: 0; overflow: hidden; }
.form-help { margin-top: 14px; font-size: 0.88rem; color: var(--text-muted); text-align: center; }
.form-help a { color: var(--blue-deep); font-weight: 600; }
.form-status { margin-top: 14px; font-size: 0.95rem; font-weight: 600; min-height: 1.2em; color: #0a6b34; text-align: center; }
.form-status.error { color: #b91c1c; }

/* ---- buttons ---- */
.btn { display: inline-block; padding: 15px 30px; border-radius: 8px; font-weight: 700; text-decoration: none; border: none; cursor: pointer; transition: background .25s, color .25s, transform .25s; font-size: 1rem; font-family: inherit; }
.btn-primary { background: var(--lime); color: var(--navy); }
.btn-primary:hover { background: #b9dc4f; transform: translateY(-2px); }
.btn-primary:disabled { opacity: .6; cursor: wait; transform: none; }
.btn-secondary { border: 2px solid rgba(255,255,255,.7); color: #fff; }
.btn-secondary:hover { background: #fff; color: var(--navy); }
.btn-block { width: 100%; font-size: 1.08rem; }
.inquiry-form .btn-primary { background: var(--navy); color: #fff; }
.inquiry-form .btn-primary:hover { background: var(--blue-deep); }

/* ---- footer ---- */
footer { background: var(--navy-2); color: #94a8bb; padding: 52px 0; text-align: center; border-top: 1px solid #17293c; }
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 12px; }
.footer-brand { display: flex; align-items: center; gap: 10px; }
.footer-brand .brand-mark { width: 32px; height: 32px; }
.footer-brand .brand-name { font-size: 1.3rem; color: var(--blue); }
.footer-brand .brand-accent { color: var(--lime); }
.footer-tag { color: #c3d1de; font-weight: 500; }
.footer-copy { font-size: 0.85rem; }
footer a { color: #c3d1de; }

/* ---- responsive ---- */
@media (max-width: 860px) {
    .nav-toggle { display: inline-flex; }
    .nav-links { display: none; position: absolute; top: 100%; left: 0; right: 0; background: #fff; flex-direction: column; align-items: stretch; gap: 0; padding: 8px 5% 18px; box-shadow: 0 14px 20px rgba(13,27,42,0.10); }
    .nav-links.open { display: flex; }
    .nav-links li { border-bottom: 1px solid var(--gray); }
    .nav-links li:last-child { border-bottom: 0; padding-top: 12px; }
    .nav-links a { display: block; padding: 14px 4px; }
    .nav-links a.btn-nav { text-align: center; margin-top: 10px; }
    .nav-links li:has(.btn-nav) { border-bottom: 0; }
    .lang-switch select { width: 100%; padding: 12px; }
    .hero h1 { font-size: 2.3rem; }
    .section-title { font-size: 1.9rem; }
    .product-layout { grid-template-columns: 1fr; gap: 34px; }
    .paper, .paper.reverse { grid-template-columns: 1fr; gap: 24px; }
    .paper.reverse .paper-figure { order: 0; }
    .form-row { flex-direction: column; gap: 20px; }
    .inquiry-form { padding: 26px 20px; }
}
@media (max-width: 640px) { .coverage-row { grid-template-columns: 1fr; gap: 12px; } }

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
    .card:hover, .btn-primary:hover { transform: none; }
}