:root {
  --navy: #0b1b2b;
  --navy-soft: #13293d;
  --amber: #f59e0b;
  --amber-dark: #b45309;
  --sky: #0ea5e9;
  --ink: #0f172a;
  --muted: #5b6b7f;
  --line: #e3e9f0;
  --bg: #f7f9fc;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(11, 27, 43, 0.08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Be Vietnam Pro", "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: #fff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a { color: var(--amber-dark); }

.wrap { width: 100%; max-width: 1140px; margin: 0 auto; padding: 0 20px; }

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  align-items: center;
  gap: 18px;
  min-height: 64px;
}

.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--navy); }
.brand__mark { width: 46px; height: 46px; flex: none; object-fit: contain; }
.brand__name { font-weight: 800; font-size: 15px; letter-spacing: -0.2px; line-height: 1.1; }
.brand__sub { display: block; font-weight: 500; font-size: 10.5px; color: var(--muted); letter-spacing: 0.6px; text-transform: uppercase; }

.nav__links { display: flex; gap: 20px; margin-left: auto; }
.nav__links a { color: var(--navy); text-decoration: none; font-size: 14px; font-weight: 600; }
.nav__links a:hover { color: var(--amber-dark); }

.nav__cta {
  background: var(--navy);
  color: #fff;
  border-radius: 999px;
  padding: 9px 18px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}
.nav__cta:hover { background: var(--navy-soft); }

.nav__toggle {
  display: none;
  margin-left: auto;
  background: none;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 7px 10px;
  font-size: 18px;
  line-height: 1;
}

/* ---------- hero ---------- */
.hero {
  position: relative;
  color: #fff;
  background:
    linear-gradient(115deg, rgba(11, 27, 43, 0.94) 0%, rgba(11, 27, 43, 0.72) 55%, rgba(11, 27, 43, 0.45) 100%),
    url("../images/hero-solar.jpg") center/cover no-repeat;
}
.hero__inner { padding: 64px 0 60px; max-width: 720px; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--amber);
  margin: 0 0 14px;
}
.hero h1 { font-size: 38px; line-height: 1.15; margin: 0 0 14px; letter-spacing: -0.6px; }
.hero h1 em { font-style: normal; color: var(--amber); }
.hero p { font-size: 16px; color: #d8e3ef; margin: 0 0 22px; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-radius: 999px;
  padding: 12px 22px;
  font-weight: 700;
  font-size: 15px;
  text-decoration: none;
  border: 0;
  cursor: pointer;
}
.btn--amber { background: var(--amber); color: #20160a; }
.btn--amber:hover { background: #fbbf24; }
.btn--ghost { background: rgba(255, 255, 255, 0.12); color: #fff; box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.4); }
.btn--ghost:hover { background: rgba(255, 255, 255, 0.2); }
.btn--navy { background: var(--navy); color: #fff; }
.btn--navy:hover { background: var(--navy-soft); }
.btn--block { width: 100%; justify-content: center; }

.hero__stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  background: rgba(255, 255, 255, 0.18);
  border-top: 1px solid rgba(255, 255, 255, 0.18);
}
.hero__stat { background: rgba(11, 27, 43, 0.72); padding: 16px 20px; }
.hero__stat b { display: block; font-size: 22px; color: var(--amber); line-height: 1.2; }
.hero__stat span { font-size: 12.5px; color: #cdd9e6; }

/* ---------- sections ---------- */
section { padding: 56px 0; }
.sec--tint { background: var(--bg); }
.sec--navy { background: var(--navy); color: #fff; }
.sec--navy p, .sec--navy li { color: #cfdbe8; }

.sec-head { max-width: 680px; margin-bottom: 28px; }
.sec-head--center { margin-left: auto; margin-right: auto; text-align: center; }
.sec-head h2 { font-size: 27px; line-height: 1.25; margin: 0 0 10px; letter-spacing: -0.4px; }
.sec-head p { margin: 0; color: var(--muted); font-size: 15.5px; }
.sec--navy .sec-head h2 { color: #fff; }
.eyebrow--dark { color: var(--amber-dark); }

.grid { display: grid; gap: 18px; }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.card h3 { font-size: 18px; margin: 14px 0 8px; }
.card p { margin: 0 0 12px; color: var(--muted); font-size: 14.5px; }
.card ul { margin: 0; padding-left: 18px; color: var(--ink); font-size: 14px; }
.card ul li { margin-bottom: 5px; }
.card__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: #fff7ed;
  color: var(--amber-dark);
  font-weight: 800;
  font-size: 15px;
}
.card--service { display: flex; flex-direction: column; }
.card--service .card__media { border-radius: 12px; overflow: hidden; margin-bottom: 14px; aspect-ratio: 16 / 9; }
.card--service .card__media img { width: 100%; height: 100%; object-fit: cover; }
.card__link { margin-top: auto; font-weight: 700; font-size: 14px; text-decoration: none; color: var(--amber-dark); }

/* ---------- packages ---------- */
.pkg {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
}
.pkg--hot { border-color: var(--amber); box-shadow: 0 14px 34px rgba(245, 158, 11, 0.18); }
.pkg__tag {
  align-self: flex-start;
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  background: #fff7ed;
  color: var(--amber-dark);
  border-radius: 999px;
  padding: 4px 10px;
  margin-bottom: 10px;
}
.pkg__size { font-size: 28px; font-weight: 800; letter-spacing: -0.8px; margin: 0; }
.pkg__for { color: var(--muted); font-size: 14px; margin: 2px 0 14px; }
.pkg__rows { list-style: none; margin: 0 0 16px; padding: 0; font-size: 14.5px; }
.pkg__rows li { display: flex; justify-content: space-between; gap: 10px; padding: 7px 0; border-bottom: 1px dashed var(--line); }
.pkg__rows li b { font-weight: 700; }

/* ---------- calculator ---------- */
.calc {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.calc__fields { display: grid; gap: 12px; }
.field { display: flex; flex-direction: column; gap: 5px; }
.field label { font-size: 13px; font-weight: 700; color: var(--navy); }
.field input, .field select {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 15px;
  font-family: inherit;
  background: #fff;
  color: var(--ink);
  width: 100%;
}
.field small { color: var(--muted); font-size: 11.5px; }
.field--2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

.calc__out { background: var(--bg); border-radius: 12px; padding: 18px; }
.calc__grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.metric { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; }
.metric span { display: block; font-size: 11.5px; color: var(--muted); }
.metric b { font-size: 19px; letter-spacing: -0.4px; }
.calc__note { font-size: 11.5px; color: var(--muted); margin: 12px 0 0; }

/* ---------- misc blocks ---------- */
.steps { counter-reset: s; display: grid; gap: 14px; }
.step { display: flex; gap: 14px; align-items: flex-start; }
.step__n {
  flex: none; width: 30px; height: 30px; border-radius: 10px;
  background: var(--amber); color: #20160a; font-weight: 800; font-size: 14px;
  display: flex; align-items: center; justify-content: center;
}
.step h3 { margin: 2px 0 4px; font-size: 16px; }
.step p { margin: 0; font-size: 14.5px; color: var(--muted); }
.sec--navy .step p { color: #b9c8d8; }
.sec--navy .step h3 { color: #fff; }

.brandbox { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; }
.brandbox h3 { margin: 0 0 6px; font-size: 16px; }
.brandbox p { margin: 0; font-size: 14px; color: var(--muted); }
.brandbox span { display: inline-block; margin-top: 10px; font-size: 12px; font-weight: 700; color: var(--amber-dark); }

.proj { border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); background: #fff; }
.proj img { aspect-ratio: 4 / 3; object-fit: cover; width: 100%; }
.proj div { padding: 12px 14px; }
.proj b { display: block; font-size: 15px; }
.proj span { font-size: 13px; color: var(--muted); }

details.faq {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
  margin-bottom: 10px;
}
details.faq summary { font-weight: 700; cursor: pointer; font-size: 15px; }
details.faq p { margin: 10px 0 0; color: var(--muted); font-size: 14.5px; }

/* ---------- contact ---------- */
.contact { display: grid; grid-template-columns: 1fr 1.1fr; gap: 24px; align-items: start; }
.contact__info { list-style: none; margin: 18px 0 0; padding: 0; font-size: 15px; }
.contact__info li { margin-bottom: 10px; }
.contact__info b { display: block; font-size: 12px; text-transform: uppercase; letter-spacing: 0.8px; color: var(--amber); }
.contact__info a { color: #fff; text-decoration: none; }
.form {
  background: #fff;
  border-radius: var(--radius);
  padding: 20px;
  display: grid;
  gap: 12px;
  color: var(--ink);
}
.form textarea {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  font: inherit;
  font-size: 15px;
  min-height: 84px;
  resize: vertical;
}
.form__msg { font-size: 13px; color: var(--muted); margin: 0; }

/* ---------- footer ---------- */
.site-footer { background: #071320; color: #9fb3c6; padding: 34px 0 24px; font-size: 14px; }
.site-footer a { color: #cfdbe8; text-decoration: none; }
.site-footer h4 { color: #fff; font-size: 13px; text-transform: uppercase; letter-spacing: 0.8px; margin: 0 0 10px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: 6px; }
.foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 24px; }
.foot-logo {
  width: 150px;
  height: auto;
  display: block;
  background: #fff;
  border-radius: 18px;
  padding: 10px;
  margin-bottom: 12px;
}
.foot-bottom { border-top: 1px solid rgba(255, 255, 255, 0.12); margin-top: 24px; padding-top: 14px; font-size: 12.5px; }

.crumbs { font-size: 13px; color: var(--muted); padding: 14px 0 0; }
.crumbs a { color: var(--muted); text-decoration: none; }

.prose p { font-size: 15.5px; color: var(--muted); }
.prose h3 { font-size: 18px; margin: 22px 0 8px; color: var(--ink); }
.prose ul { color: var(--muted); font-size: 15px; }

.fab {
  position: fixed;
  right: 14px;
  bottom: 14px;
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.fab a {
  background: var(--amber);
  color: #20160a;
  font-weight: 800;
  font-size: 13px;
  border-radius: 999px;
  padding: 10px 16px;
  text-decoration: none;
  box-shadow: var(--shadow);
}
.fab a.fab--zalo { background: #0068ff; color: #fff; }

@media (max-width: 900px) {
  .grid--3, .grid--4, .grid--2 { grid-template-columns: 1fr 1fr; }
  .calc, .contact, .foot-grid { grid-template-columns: 1fr; }
  .hero__stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .nav__links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    gap: 0;
    padding: 6px 20px 14px;
  }
  .nav__links.is-open { display: flex; }
  .nav__links a { padding: 10px 0; border-bottom: 1px solid var(--line); }
  .nav__toggle { display: block; }
  .nav__cta { display: none; }
  .hero__inner { padding: 40px 0 36px; }
  .hero h1 { font-size: 27px; }
  .hero p { font-size: 15px; }
  section { padding: 38px 0; }
  .sec-head h2 { font-size: 22px; }
  .grid--3, .grid--4, .grid--2 { grid-template-columns: 1fr; }
  .calc { padding: 16px; }
  .calc__grid { gap: 8px; }
  .metric b { font-size: 17px; }
  .fab {
    left: 10px;
    right: 10px;
    bottom: 10px;
    flex-direction: row;
    gap: 10px;
  }
  .fab a { flex: 1; text-align: center; padding: 12px 8px; }
  .contact { padding-bottom: 70px; }
  .foot-logo { width: 130px; }
}