:root {
  --accent: #6d28d9;
  --accent-dark: #5521a8;
  --accent-soft: #f4f0ff;
  --ink: #17171f;
  --muted: #5f6370;
  --line: #e6e7eb;
  --surface: #ffffff;
  --surface-muted: #f8f8fb;
  --success: #116b4f;
  --radius: 8px;
  --shadow: 0 12px 30px rgba(23, 23, 31, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--surface);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  letter-spacing: 0;
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover,
a:focus {
  color: var(--accent-dark);
  text-decoration: underline;
}

h1,
h2,
h3 {
  margin: 0 0 0.75rem;
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(2.05rem, 3.2vw, 2.75rem);
}

h2 {
  font-size: clamp(1.45rem, 2vw, 1.8rem);
}

h3 {
  font-size: 1.08rem;
}

p {
  margin: 0 0 1rem;
}

ul,
ol {
  margin: 0 0 1.25rem;
  padding-left: 1.25rem;
}

li + li {
  margin-top: 0.35rem;
}

.container {
  width: min(100% - 2rem, 1100px);
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--ink);
  font-weight: 700;
  font-size: 1.1rem;
}

.brand:hover,
.brand:focus {
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 7px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.1rem;
}

.site-nav a {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.95rem;
}

.site-nav a:hover,
.site-nav a:focus,
.site-nav a[aria-current="page"] {
  color: var(--accent);
  text-decoration: none;
}

.site-nav .nav-cta {
  color: #ffffff;
  background: var(--accent);
  padding: 0.55rem 0.85rem;
  border-radius: var(--radius);
}

.site-nav .nav-cta:hover,
.site-nav .nav-cta:focus,
.site-nav .nav-cta[aria-current="page"] {
  color: #ffffff;
  background: var(--accent-dark);
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
}

.nav-toggle span {
  width: 18px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
}

.hero {
  position: relative;
  overflow: hidden;
  min-height: 520px;
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--line);
  background: #fbfaff;
}

.hero-content {
  position: relative;
  padding: 6rem 0;
}

.hero-watermark {
  position: absolute;
  right: 2rem;
  top: 50%;
  width: 256px;
  height: 256px;
  transform: translateY(-50%);
  opacity: 0.14;
  filter: saturate(0.9);
  pointer-events: none;
}

.hero h1,
.hero .lead,
.hero-copy,
.button-row {
  position: relative;
  max-width: 720px;
}

.hero h1 {
  font-size: clamp(2.35rem, 4vw, 3rem);
}

.lead {
  color: var(--ink);
  font-size: 1.18rem;
}

.hero-copy {
  color: var(--muted);
  font-size: 1rem;
}

.eyebrow {
  margin-bottom: 0.75rem;
  color: var(--accent);
  font-weight: 700;
  font-size: 0.82rem;
  text-transform: uppercase;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0.72rem 1rem;
  font-weight: 700;
  line-height: 1.1;
  text-align: center;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}

.button:hover,
.button:focus {
  text-decoration: none;
  transform: translateY(-1px);
}

.button-primary {
  color: #ffffff;
  background: var(--accent);
  border-color: var(--accent);
}

.button-primary:hover,
.button-primary:focus {
  color: #ffffff;
  background: var(--accent-dark);
  border-color: var(--accent-dark);
}

.button-secondary {
  color: var(--accent);
  background: var(--accent-soft);
  border-color: #ded4ff;
}

.button-secondary:hover,
.button-secondary:focus {
  color: var(--accent-dark);
  background: #ebe3ff;
}

.button-ghost {
  color: var(--ink);
  background: var(--surface);
  border-color: var(--line);
}

.button-ghost:hover,
.button-ghost:focus {
  color: var(--accent);
  border-color: #cfc5f3;
}

.button-large {
  min-width: 190px;
}

.section {
  padding: 4.5rem 0;
}

.section-tight {
  padding-top: 3.5rem;
}

.section-muted {
  background: var(--surface-muted);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section-heading {
  max-width: 680px;
  margin-bottom: 1.75rem;
}

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

.card,
.info-panel,
.purchase-panel,
.feedback-form {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.card {
  padding: 1.25rem;
}

.card p {
  color: var(--muted);
}

.two-column {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 3rem;
  align-items: start;
}

.plain-list p:last-child {
  margin-bottom: 0;
}

.note {
  color: var(--success);
  font-weight: 700;
}

.purchase-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 1.5rem;
}

.purchase-panel p:last-child {
  margin-bottom: 0;
}

.page-main {
  min-height: calc(100vh - 220px);
}

.content-narrow {
  max-width: 780px;
}

.content-narrow h1 {
  margin-bottom: 0.85rem;
}

.content-narrow h2,
.doc-content h2 {
  margin-top: 1.6rem;
}

.info-panel {
  padding: 1.5rem;
  margin: 2rem 0;
}

.section-nested {
  margin-top: 2.5rem;
}

.check-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
  padding: 0;
  list-style: none;
}

.check-list li {
  margin: 0;
  padding: 0.6rem 0.7rem;
  background: var(--accent-soft);
  border-radius: var(--radius);
  font-weight: 700;
}

.check-list.compact {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  max-width: 420px;
}

.statement-list {
  padding-left: 1.1rem;
}

.doc-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 3rem;
  align-items: start;
}

.toc {
  position: sticky;
  top: 96px;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.toc a {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.88rem;
}

.toc a:hover,
.toc a:focus {
  color: var(--accent);
  text-decoration: none;
}

.doc-content {
  max-width: 760px;
  line-height: 1.55;
}

.doc-content section {
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}

.doc-content section:last-child {
  border-bottom: 0;
}

.troubleshooting-list {
  margin: 0;
}

.troubleshooting-list dt {
  margin-top: 1rem;
  font-weight: 700;
}

.troubleshooting-list dd {
  margin: 0.25rem 0 0;
  color: var(--muted);
}

.feedback-form {
  display: grid;
  gap: 1.15rem;
  padding: 1.5rem;
  margin-top: 1.5rem;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

label,
fieldset {
  display: grid;
  gap: 0.45rem;
  margin: 0;
}

label span,
legend {
  color: var(--ink);
  font-weight: 700;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid #cfd2da;
  border-radius: var(--radius);
  padding: 0.75rem 0.8rem;
  color: var(--ink);
  background: var(--surface);
  font: inherit;
}

textarea {
  resize: vertical;
}

input:focus,
select:focus,
textarea:focus {
  outline: 3px solid #ded4ff;
  border-color: var(--accent);
}

.rating-fieldset {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
}

.rating-options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.rating-options label {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-muted);
  cursor: pointer;
}

.rating-options input {
  width: auto;
}

.rating-message {
  min-height: 1.5rem;
  margin: 0.4rem 0 0;
  color: var(--muted);
  font-weight: 700;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--surface-muted);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.5rem 0;
}

.footer-inner p {
  margin: 0;
  color: var(--muted);
}

.footer-inner nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
}

.footer-inner a {
  color: var(--muted);
  font-weight: 600;
}

.footer-inner a:hover,
.footer-inner a:focus {
  color: var(--accent);
  text-decoration: none;
}

@media (max-width: 900px) {
  h1 {
    font-size: clamp(2rem, 5vw, 2.45rem);
  }

  h2 {
    font-size: clamp(1.4rem, 3.5vw, 1.65rem);
  }

  .hero {
    min-height: 460px;
  }

  .hero-content {
    padding: 5rem 0;
  }

  .hero-watermark {
    right: -2rem;
    opacity: 0.1;
  }

  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .two-column,
  .doc-layout {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .toc {
    position: static;
  }
}

@media (max-width: 760px) {
  .header-inner {
    min-height: 64px;
    align-items: flex-start;
    padding: 0.8rem 0;
  }

  .brand {
    min-height: 42px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: absolute;
    left: 1rem;
    right: 1rem;
    top: 64px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav a {
    padding: 0.75rem;
  }

  .site-nav .nav-cta {
    margin-top: 0.25rem;
    text-align: center;
  }

  .hero {
    min-height: 420px;
  }

  .hero-content {
    padding: 4rem 0;
  }

  .lead {
    font-size: 1.08rem;
  }

  .card-grid,
  .form-grid,
  .check-list,
  .check-list.compact {
    grid-template-columns: 1fr;
  }

  .purchase-panel,
  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .button-row,
  .button,
  .purchase-panel .button {
    width: 100%;
  }
}

@media (max-width: 520px) {
  .container {
    width: min(100% - 1.25rem, 1100px);
  }

  h1 {
    font-size: 1.95rem;
  }

  .hero h1 {
    font-size: 2.15rem;
  }

  h2 {
    font-size: 1.35rem;
  }

  .section {
    padding: 3rem 0;
  }

  .hero-watermark {
    width: 190px;
    height: 190px;
    right: -3rem;
  }

  .rating-options {
    flex-direction: column;
  }
}