:root {
  --pri: #f59734;
  --pri-dark: #d97a16;
  --sec: #0560a1;
  --sec-dark: #03467a;
  --cyan: #00c8c0;
  --text: #15191e;
  --muted: #5c6773;
  --line: #e6ebf0;
  --bg: #ffffff;
  --bg-soft: #f4f7fa;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(5, 96, 161, 0.08);
  --container: 1240px;
  --header-h: 74px;
  --font: 'Manrope', 'Inter', sans-serif;
  --body: 'Inter', sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--text);
  background: var(--bg);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.6;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
h1, h2, h3, p { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }

.container {
  width: min(var(--container), calc(100% - 32px));
  margin: 0 auto;
}
.container--narrow { width: min(760px, calc(100% - 32px)); }
.container--content { width: min(820px, calc(100% - 32px)); }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font);
  font-weight: 700;
  cursor: pointer;
}
.btn-lg { min-height: 52px; padding: 0 24px; }
.btn-block { width: 100%; }
.btn-primary { background: var(--pri); color: #fff; }
.btn-primary:hover { background: var(--pri-dark); }
.btn-secondary { background: var(--sec); color: #fff; }
.btn-secondary:hover { background: var(--sec-dark); }
.btn-outline { background: #fff; color: var(--sec); border-color: #c9d7e4; }
.btn-outline:hover { border-color: var(--sec); }
.btn-ghost { background: transparent; color: var(--sec); }

.kicker, .section-label {
  margin-bottom: 8px;
  color: var(--pri);
  font-family: var(--font);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.section { padding: 72px 0; }
.section-muted { background: var(--bg-soft); }
.section-head { max-width: 760px; margin: 0 auto 32px; text-align: center; }
.section-head h2, .content-heading, .static-page-title {
  font-family: var(--font);
  font-size: clamp(1.7rem, 3vw, 2.4rem);
  line-height: 1.2;
  letter-spacing: -0.03em;
}
.section-lead, .content-text, .static-page-lead {
  margin-top: 12px;
  color: var(--muted);
}
.content-heading--center { text-align: center; }
.section-cta { margin-top: 28px; text-align: center; }
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.icon-bubble {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: rgba(5, 96, 161, 0.08);
  color: var(--sec);
  flex-shrink: 0;
}
.icon-bubble svg, .feature-icon svg { width: 28px; height: 28px; }

.topbar {
  background: var(--sec-dark);
  color: rgba(255, 255, 255, 0.86);
  font-size: 0.85rem;
}
.topbar-inner, .header-inner, .advantage-grid, .hero-grid, .coverage-inner, .about-band-grid, .footer-grid {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.topbar-inner { min-height: 38px; }
.topbar a:hover { color: var(--cyan); }
.topbar-links { display: flex; gap: 16px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid transparent;
  backdrop-filter: blur(12px);
}
.site-header.scrolled { border-bottom-color: var(--line); box-shadow: var(--shadow); }
.header-inner { height: 100%; }
.logo { display: inline-flex; align-items: center; gap: 10px; }
.logo-word {
  font-family: var(--font);
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--sec);
}
.logo-word span { color: var(--pri); }
.main-nav { flex: 1; }
.nav-list { display: flex; justify-content: center; gap: 4px; }
.nav-item { position: relative; }
.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 8px;
  border: 0;
  background: none;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 700;
  cursor: pointer;
}
.nav-link:hover, .nav-link.is-active { color: var(--sec); }
.dropdown-panel {
  position: absolute;
  top: calc(100% - 4px);
  left: 0;
  min-width: 220px;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  box-shadow: var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
}
.has-dropdown.open .dropdown-panel, .has-dropdown:hover .dropdown-panel {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.dropdown-item {
  display: block;
  padding: 10px 12px;
  border-radius: 10px;
  font-weight: 600;
}
.dropdown-item:hover { background: var(--bg-soft); color: var(--sec); }
.header-actions { display: flex; align-items: center; gap: 8px; }
.mobile-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 0;
  background: transparent;
}
.mobile-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: var(--text);
}

.hero {
  background:
    radial-gradient(circle at 15% 20%, rgba(0, 200, 192, 0.25), transparent 28%),
    radial-gradient(circle at 80% 10%, rgba(245, 151, 52, 0.28), transparent 26%),
    linear-gradient(120deg, #0670b8 0%, #034a80 55%, #02345c 100%);
  color: #fff;
}
.hero-grid { min-height: 520px; padding: 48px 0; }
.hero-title {
  font-family: var(--font);
  font-size: clamp(2.4rem, 5vw, 4.2rem);
  line-height: 0.95;
  letter-spacing: -0.04em;
}
.hero-title span { color: var(--cyan); }
.hero-lead { max-width: 460px; margin: 18px 0 24px; color: rgba(255, 255, 255, 0.88); }
.dash {
  width: min(460px, 100%);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.18);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.18);
  overflow: hidden;
}
.dash-top, .dash-row, .dash-meters div {
  display: flex;
  align-items: center;
  gap: 8px;
}
.dash-top { padding: 12px 14px; background: rgba(0, 0, 0, 0.16); font-size: 0.85rem; }
.dash-top span {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #ffb4a2;
}
.dash-top span:nth-child(2) { background: #ffe08a; }
.dash-top span:nth-child(3) { background: #8ef0c8; }
.dash-top strong { margin-left: auto; font-weight: 600; }
.dash-body { padding: 16px; }
.dash-row {
  justify-content: space-between;
  margin-bottom: 10px;
  padding: 12px 14px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.08);
}
.dash-row span {
  color: var(--cyan);
  font-size: 0.78rem;
  font-weight: 700;
}
.dash-meters { display: grid; gap: 8px; margin-top: 14px; }
.dash-meters div { gap: 10px; font-size: 0.78rem; }
.dash-meters i {
  display: block;
  height: 6px;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--cyan), var(--pri));
}

.advantage { background: #fff; border-bottom: 1px solid var(--line); }
.advantage-grid { display: grid; grid-template-columns: repeat(3, 1fr); padding: 22px 0; }
.advantage-item { display: flex; gap: 12px; align-items: flex-start; }
.advantage-item h2 { font-family: var(--font); font-size: 1rem; }
.advantage-item p { color: var(--muted); font-size: 0.92rem; }

.card-grid { display: grid; gap: 18px; }
.card-grid--3 { grid-template-columns: repeat(3, 1fr); }
.card-grid--4 { grid-template-columns: repeat(4, 1fr); }

.system-card, .product-card, .vps-card, .gpu-card, .review-card, .feature-card, .contact-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow);
}
.system-card { display: block; }
.system-card:hover, .product-card:hover, .vps-card:hover { border-color: #b9d4ea; }
.system-card h3, .product-name, .feature-card-title, .contact-card-title {
  margin: 12px 0 8px;
  font-family: var(--font);
  font-size: 1.15rem;
}
.system-card p, .review-card blockquote, .feature-card-desc { color: var(--muted); }

.product-card { position: relative; display: flex; flex-direction: column; }
.product-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  padding: 4px 8px;
  border-radius: 999px;
  background: #fff1e2;
  color: var(--pri-dark);
  font-size: 0.75rem;
  font-weight: 800;
}
.product-price { margin-bottom: 12px; color: var(--muted); }
.product-price strong {
  display: block;
  color: var(--sec);
  font-family: var(--font);
  font-size: 1.7rem;
  letter-spacing: -0.03em;
}
.product-price s { color: #98a2ad; margin-right: 6px; }
.spec-list { margin-bottom: 18px; }
.spec-list li {
  position: relative;
  padding: 6px 0 6px 22px;
  border-top: 1px solid var(--line);
}
.spec-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  width: 8px;
  height: 5px;
  border-left: 2px solid var(--sec);
  border-bottom: 2px solid var(--sec);
  transform: rotate(-45deg);
}
.product-card .btn, .vps-card .btn, .gpu-card .btn { margin-top: auto; }

.highlight-list { display: grid; gap: 14px; }
.highlight-item {
  display: flex;
  gap: 14px;
  padding: 16px;
  border-radius: 14px;
  background: #fff;
}
.highlight-item h3 { font-family: var(--font); }
.highlight-item p { color: var(--muted); }

.tab-list { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 18px; }
.tab-btn {
  min-height: 42px;
  padding: 0 16px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  font-family: var(--font);
  font-weight: 700;
  cursor: pointer;
}
.tab-btn.is-active { background: var(--sec); border-color: var(--sec); color: #fff; }
.tab-intro { margin-bottom: 16px; color: var(--muted); }

.coverage {
  background: var(--sec);
  color: #fff;
}
.coverage-inner { padding: 48px 0; align-items: flex-start; }
.coverage-stat strong {
  display: block;
  font-family: var(--font);
  font-size: 4rem;
  line-height: 1;
}
.coverage h2 { font-family: var(--font); font-size: 1.8rem; max-width: 640px; }
.coverage p { max-width: 640px; color: rgba(255, 255, 255, 0.86); }

.about-band-grid { align-items: center; }
.about-stat {
  min-width: 220px;
  padding: 28px;
  border-radius: 20px;
  background: #fff6ec;
  text-align: center;
}
.about-stat strong {
  display: block;
  color: var(--pri);
  font-family: var(--font);
  font-size: 3rem;
}
.review-card blockquote { font-size: 0.98rem; }
.review-card figcaption { margin-top: 16px; }
.review-card span { display: block; color: var(--muted); font-size: 0.88rem; }

.faq-item, .sidebar-faq-item {
  border-bottom: 1px solid var(--line);
}
.faq-item summary, .sidebar-faq-item summary {
  padding: 16px 0;
  cursor: pointer;
  font-family: var(--font);
  font-weight: 700;
}
.faq-item p, .sidebar-faq-item p { margin: 0 0 16px; color: var(--muted); }

.site-footer {
  background: #06243d;
  color: rgba(255, 255, 255, 0.82);
  padding: 48px 0 24px;
}
.site-footer .logo-word { color: #fff; }
.footer-grid { align-items: flex-start; display: grid; grid-template-columns: 1.3fr repeat(3, 1fr); }
.footer-desc { margin-top: 12px; max-width: 320px; }
.footer-title { margin-bottom: 10px; color: #fff; font-family: var(--font); }
.footer-col a { display: inline-block; padding: 4px 0; }
.footer-col a:hover { color: var(--cyan); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 28px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 0.9rem;
}
.footer-legal { display: flex; gap: 14px; }
.contact-fab {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 30;
  padding: 12px 16px;
  border-radius: 999px;
  background: var(--pri);
  color: #fff;
  font-family: var(--font);
  font-weight: 800;
  box-shadow: 0 10px 24px rgba(245, 151, 52, 0.35);
}

.breadcrumb { padding: 18px 0 0; color: var(--muted); font-size: 0.9rem; }
.breadcrumb-list { display: flex; gap: 8px; flex-wrap: wrap; }
.breadcrumb-list li:not(:last-child)::after { content: "/"; margin-left: 8px; }
.static-page-header { padding: 28px 0 8px; }
.static-page-meta { margin-top: 8px; color: var(--muted); font-size: 0.92rem; }
.static-section { padding: 36px 0; }
.static-section--alt { background: var(--bg-soft); }
.about-stats { padding-bottom: 10px; }
.stats-grid, .contact-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.stat-box {
  padding: 18px;
  border-radius: 16px;
  background: var(--bg-soft);
  text-align: center;
}
.stat-box-value { font-family: var(--font); font-size: 1.8rem; color: var(--sec); }
.stat-box-label { color: var(--muted); }
.values-list { display: grid; gap: 10px; margin-top: 16px; }
.values-list li { display: flex; gap: 10px; align-items: flex-start; }
.values-list svg { color: var(--sec); flex-shrink: 0; margin-top: 2px; }
.ecosystem-banner {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: center;
  padding: 28px;
  border-radius: 20px;
  background: #fff;
}
.feature-icon { color: var(--sec); }

.contact-grid { grid-template-columns: repeat(4, 1fr); }
.contact-card { display: block; }
.contact-card-icon { color: var(--sec); }
.contact-card-icon svg { width: 28px; height: 28px; }
.contact-card-value { font-weight: 700; }
.contact-card-note { color: var(--muted); font-size: 0.9rem; }
.contact-layout { display: grid; grid-template-columns: 1.4fr 0.8fr; gap: 28px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.form-group { margin-bottom: 14px; }
.form-group label { display: block; margin-bottom: 6px; font-weight: 600; }
.form-group input, .form-group select, .form-group textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
}
.form-note, .sidebar-text { color: var(--muted); }
.sidebar-block {
  margin-bottom: 16px;
  padding: 18px;
  border-radius: 16px;
  background: #fff;
}
.sidebar-title { margin-bottom: 8px; font-family: var(--font); }
.terms-layout { display: grid; grid-template-columns: 240px 1fr; gap: 28px; }
.terms-toc {
  position: sticky;
  top: 90px;
  align-self: start;
  padding: 16px;
  border-radius: 16px;
  background: var(--bg-soft);
}
.terms-toc-title { margin-bottom: 8px; font-family: var(--font); }
.terms-toc a { display: block; padding: 6px 0; color: var(--muted); }
.terms-toc a:hover { color: var(--sec); }
.terms-block { margin-bottom: 22px; }
.terms-block-title { margin-bottom: 8px; font-family: var(--font); font-size: 1.25rem; }
.terms-block p { margin: 0 0 8px; color: var(--muted); }
.terms-footer-note { margin-top: 12px; }
.section-404 { padding: 48px 0 80px; }

article[id], section[id], fieldset[id] { scroll-margin-top: 90px; }

.product-lines { padding-bottom: 12px; }
.product-lines .system-card h2 { margin-top: 0; font-size: 1.35rem; }
.product-card.is-popular { border-color: var(--sec); }

.install-steps { margin: 12px 0 18px; padding-left: 18px; color: var(--muted); }
.install-steps li { margin: 6px 0; list-style: decimal; }
.download-note { margin: 22px auto 0; text-align: center; }

.phone-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.phone-card {
  padding: 22px;
  border: 1.5px solid var(--line);
  border-radius: 22px;
  background: #fff;
  box-shadow: var(--shadow);
  cursor: pointer;
}
.phone-card.is-selected {
  border-color: #1f9d55;
  background: linear-gradient(#fff, #fff) padding-box, linear-gradient(180deg, #e8fff3, #fff 40%) border-box;
  background: linear-gradient(180deg, #f3fff8 0%, #fff 42%);
}
.phone-card-top { display: flex; justify-content: space-between; align-items: center; }
.phone-card h3 { font-family: var(--font); font-size: 1.7rem; letter-spacing: -0.03em; }
.phone-check {
  width: 28px;
  height: 28px;
  border: 2px solid #d5dde5;
  border-radius: 50%;
}
.phone-card.is-selected .phone-check {
  border-color: #1f9d55;
  background: #1f9d55 url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M3.5 8.2l2.6 2.7 6-6.4' fill='none' stroke='white' stroke-width='2' stroke-linecap='round'/%3E%3C/svg%3E") center / 16px no-repeat;
}
.phone-badge { display: inline-block; margin: 8px 0; color: #2458d6; font-weight: 700; font-size: 0.92rem; }
.phone-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 0;
  font-weight: 700;
}
.phone-features li::before {
  content: "";
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #14944a;
  flex-shrink: 0;
}
.bill-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 16px; }
.bill-pill {
  padding: 10px 6px;
  border: 1px solid #e4e9ef;
  border-radius: 12px;
  background: #f7f9fb;
  text-align: center;
  cursor: pointer;
}
.bill-pill small { display: block; color: #8b97a3; font-size: 0.72rem; letter-spacing: 0.06em; text-transform: uppercase; }
.bill-pill strong { color: #5c6773; font-family: var(--font); }
.phone-card.is-selected .bill-pill.is-on { border-color: #1f9d55; background: #fff; }
.phone-card.is-selected .bill-pill.is-on strong { color: #14944a; }

.phone-config { margin-top: 28px; display: grid; gap: 18px; }
.config-block, .phone-summary {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
}
.config-block h3, .config-block legend { font-family: var(--font); font-size: 1.15rem; margin-bottom: 10px; }
.config-block label, .config-block legend { font-weight: 700; }
.config-block select {
  display: block;
  width: min(360px, 100%);
  margin: 6px 0 14px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
}
.choice-row { display: flex; flex-wrap: wrap; gap: 10px; }
.choice {
  display: grid;
  gap: 2px;
  min-width: 120px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  cursor: pointer;
}
.choice--wide { flex: 1; min-width: 240px; }
.choice small { color: var(--muted); font-weight: 500; }
.choice:has(input:checked) { border-color: #1f9d55; background: #f3fff8; }
.choice input { accent-color: #1f9d55; }
.phone-summary { display: flex; justify-content: space-between; gap: 16px; align-items: center; }
.phone-summary p { font-weight: 700; }

.download-banner {
  margin: 0 0 18px;
  padding: 12px 16px;
  border-radius: 12px;
  background: #f3fff8;
  border: 1px solid #1f9d55;
  font-weight: 700;
}
.download-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fff;
  box-shadow: var(--shadow);
}
.download-card-title { font-family: var(--font); font-size: 1.2rem; }
.download-card-desc, .download-card-meta { color: var(--muted); }
.download-card .btn { margin-top: auto; }
.download-card.is-recommended,
.download-card.is-current {
  border-color: #1f9d55;
  box-shadow: 0 10px 28px rgba(31, 157, 85, 0.12);
}
.download-card.is-recommended .download-card-title::after {
  content: "Đề xuất";
  display: inline-block;
  margin-left: 8px;
  padding: 2px 8px;
  border-radius: 999px;
  background: #1f9d55;
  color: #fff;
  font-size: 0.72rem;
  vertical-align: middle;
}
.download-os-links { margin-top: 36px; }
.download-os-links h2 { margin-bottom: 12px; font-family: var(--font); font-size: 1.25rem; }
.download-os-links .choice { text-decoration: none; }

@media (max-width: 980px) {
  .mobile-toggle { display: block; }
  .header-actions { display: none; }
  .main-nav {
    position: fixed;
    inset: var(--header-h) 0 0 0;
    padding: 12px 16px 32px;
    background: #fff;
    transform: translateX(100%);
    transition: transform 0.2s ease;
    overflow: auto;
  }
  .main-nav.open { transform: none; }
  .nav-list, .advantage-grid, .card-grid--3, .card-grid--4, .stats-grid, .contact-grid, .footer-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }
  .nav-list { grid-template-columns: 1fr; }
  .dropdown-panel {
    position: static;
    display: none;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    margin: 0 0 8px 12px;
  }
  .has-dropdown.open .dropdown-panel { display: block; }
  .hero-grid, .coverage-inner, .about-band-grid, .contact-layout, .terms-layout, .ecosystem-banner, .footer-bottom, .topbar-inner, .phone-summary {
    display: block;
  }
  .phone-grid { grid-template-columns: 1fr; }
  .phone-summary .btn { margin-top: 12px; }
  .hero-copy { margin-top: 28px; }
  .topbar-links { margin-top: 4px; }
  .terms-toc { position: static; margin-bottom: 16px; }
}

@media (max-width: 680px) {
  .advantage-grid, .card-grid--3, .card-grid--4, .stats-grid, .contact-grid, .footer-grid, .form-row {
    grid-template-columns: 1fr;
  }
  .section { padding: 48px 0; }
  .hero-grid { min-height: 0; }
}