/* ===== Reset đơn giản ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
  background: radial-gradient(circle at top left, #111827 0, #020617 55%, #020617 100%);
  color: #e5e7eb;
}

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

a {
  color: inherit;
  text-decoration: none;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  background: linear-gradient(to right, rgba(15,23,42,0.9), rgba(15,23,42,0.6));
  border-bottom: 1px solid rgba(148,163,184,0.25);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.9rem 0;
}

.logo-block {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-mark {
  width: 36px;
  height: 36px;
  border-radius: 0.9rem;
  background: radial-gradient(circle at 20% 20%, #38bdf8, #4f46e5, #ec4899);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #f9fafb;
  font-size: 0.95rem;
  letter-spacing: 0.08em;
}

.logo-title {
  font-weight: 600;
  font-size: 1.05rem;
  color: #f9fafb;
}

.logo-sub {
  font-size: 0.8rem;
  color: #9ca3af;
}

.main-nav {
  display: flex;
  gap: 1.25rem;
  font-size: 0.9rem;
}

.main-nav a {
  color: #cbd5f5;
  padding-bottom: 0.1rem;
  border-bottom: 1px solid transparent;
  transition: 0.2s ease;
}

.main-nav a:hover {
  color: #e5e7eb;
  border-bottom-color: #38bdf8;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  border-radius: 999px;
  padding: 0.55rem 1.3rem;
  font-size: 0.9rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, #38bdf8, #4f46e5);
  color: #f9fafb;
  box-shadow: 0 14px 35px rgba(59,130,246,0.4);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 40px rgba(59,130,246,0.55);
}

.btn-ghost {
  border-color: rgba(148,163,184,0.4);
  color: #e5e7eb;
  background: rgba(15,23,42,0.6);
}

.btn-ghost:hover {
  border-color: #4b5563;
  background: rgba(31,41,55,0.8);
}

.btn-outline {
  border-color: rgba(148,163,184,0.5);
  color: #e5e7eb;
  background: transparent;
}

.btn-outline:hover {
  border-color: #38bdf8;
}

.full-width {
  width: 100%;
}

/* ===== Hero ===== */
.hero {
  padding: 2.6rem 0 1.5rem;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 2rem;
  align-items: center;
}

.hero-text h1 {
  font-size: clamp(1.9rem, 3vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.7rem;
}

.hero-text p {
  font-size: 0.95rem;
  color: #9ca3af;
  max-width: 34rem;
}

.hero-cta {
  display: flex;
  gap: 0.8rem;
  margin: 1.1rem 0;
  flex-wrap: wrap;
}

.hero-bullets {
  list-style: none;
  margin-top: 0.6rem;
  font-size: 0.88rem;
  color: #9ca3af;
}

.hero-bullets li::before {
  content: "•";
  color: #38bdf8;
  margin-right: 0.4rem;
}

.hero-card {
  border-radius: 1.2rem;
  padding: 1.1rem 1.1rem 1rem;
  border: 1px solid rgba(148,163,184,0.35);
  background:
    radial-gradient(circle at 0 0, rgba(56,189,248,0.12), transparent 55%),
    radial-gradient(circle at 100% 100%, rgba(129,140,248,0.14), transparent 55%),
    rgba(15,23,42,0.9);
  box-shadow: 0 20px 60px rgba(15,23,42,0.85);
}

.hero-card-header {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.8rem;
}

.hero-metrics {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  font-size: 0.86rem;
}

.metric-label {
  color: #9ca3af;
}

.metric-value {
  float: right;
  color: #e5e7eb;
}

.hero-note {
  margin-top: 0.9rem;
  font-size: 0.82rem;
  color: #9ca3af;
}

/* ===== Sections ===== */
.section {
  padding: 1.6rem 0 1.8rem;
}

.section-alt {
  background: radial-gradient(circle at top, rgba(30,64,175,0.32), rgba(15,23,42,1));
}

.section-heading {
  text-align: center;
  margin-bottom: 1.4rem;
}

.section-heading h2 {
  font-size: 1.4rem;
  margin-bottom: 0.35rem;
}

.section-heading p {
  font-size: 0.9rem;
  color: #9ca3af;
}

/* ===== Product grid ===== */
.product-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1.35rem;
}

.product-card {
  border-radius: 1.1rem;
  padding: 0.9rem 0.9rem 1rem;
  background: radial-gradient(circle at top, rgba(30,64,175,0.6), rgba(15,23,42,0.96));
  border: 1px solid rgba(148,163,184,0.45);
  box-shadow: 0 16px 40px rgba(15,23,42,0.9);
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.product-card:hover {
  border-color: #38bdf8;
  transform: translateY(-1px);
  transition: 0.18s ease;
}

.product-tag {
  align-self: flex-start;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #bfdbfe;
  border: 1px solid rgba(191,219,254,0.5);
}

.product-thumb {
  border-radius: 0.8rem;
  margin: 0.3rem 0;
  border: 1px solid rgba(148,163,184,0.5);
}

.product-card h3 {
  font-size: 1rem;
  margin-top: 0.1rem;
}

.product-card p {
  font-size: 0.84rem;
  color: #cbd5f5;
}

.product-points {
  list-style: none;
  font-size: 0.8rem;
  color: #9ca3af;
  margin: 0.2rem 0 0.3rem;
}

.product-points li {
  display: flex;
  align-items: flex-start;
  gap: 0.3rem;
}

.product-points li::before {
  content: "◆";
  font-size: 0.6rem;
  margin-top: 0.15rem;
  color: #38bdf8;
}

.product-price {
  margin-top: auto;
  font-size: 0.86rem;
}

.price-main {
  display: block;
  font-weight: 600;
  color: #f9fafb;
}

.price-sub {
  display: block;
  color: #9ca3af;
  font-size: 0.78rem;
  margin-bottom: 0.4rem;
}

/* ===== Feature grid ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.feature-card {
  padding: 0.9rem 0.9rem 1rem;
  border-radius: 0.9rem;
  border: 1px solid rgba(148,163,184,0.5);
  background: rgba(15,23,42,0.85);
  box-shadow: 0 10px 30px rgba(15,23,42,0.8);
  font-size: 0.88rem;
}

.feature-card h3 {
  font-size: 0.98rem;
  margin-bottom: 0.35rem;
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1.1fr);
  gap: 1.6rem;
}

.contact-list {
  list-style: none;
  margin-top: 0.8rem;
  font-size: 0.9rem;
  color: #d1d5db;
}

.contact-list li + li {
  margin-top: 0.2rem;
}

.contact-form {
  padding: 1rem 1rem 1.1rem;
  border-radius: 1rem;
  border: 1px solid rgba(148,163,184,0.45);
  background: rgba(15,23,42,0.98);
  box-shadow: 0 14px 40px rgba(15,23,42,0.95);
}

.form-row {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin-bottom: 0.6rem;
}

.form-row label {
  font-size: 0.82rem;
  color: #9ca3af;
}

.form-row input,
.form-row select,
.form-row textarea {
  background: rgba(15,23,42,0.9);
  border-radius: 0.6rem;
  border: 1px solid rgba(75,85,99,0.9);
  padding: 0.45rem 0.6rem;
  font-size: 0.86rem;
  color: #e5e7eb;
  outline: none;
}

.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
  border-color: #38bdf8;
  box-shadow: 0 0 0 1px rgba(56,189,248,0.4);
}

.form-note {
  margin-top: 0.35rem;
  font-size: 0.75rem;
  color: #6b7280;
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid rgba(148,163,184,0.35);
  margin-top: 0.8rem;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.8rem 0 1rem;
  font-size: 0.78rem;
  color: #9ca3af;
}

/* ===== Responsive ===== */
@media (max-width: 980px) {
  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
  }
  .hero-card {
    order: -1;
    margin-bottom: 0.8rem;
  }
  .product-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .contact-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 640px) {
  .header-inner {
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-start;
  }
  .main-nav {
    font-size: 0.82rem;
  }
  .product-grid {
    grid-template-columns: minmax(0, 1fr);
  }
  .feature-grid {
    grid-template-columns: minmax(0, 1fr);
  }
  .hero {
    padding-top: 1.6rem;
  }
}