/* ==========================================================
   Northstar Analytics, single-page landing site.
   Hand-authored CSS3, one external stylesheet.

   Contrast checked before writing: the lowest pair used here is
   8.70:1 (muted slate on the dark background), against the 4.5:1
   that Section 508 and WCAG AA require for normal text.
   ========================================================== */

:root {
  --bg: #0b1220;
  --panel: #111a2b;
  --text: #e8eef7;
  --muted: #9fb3c8;
  --accent: #7cc4fa;
  --accent-deep: #3c93d6;
  --border: rgba(232, 238, 247, 0.14);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text);
  background-color: var(--bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background-color: var(--accent);
  color: var(--bg);
  padding: 0.75rem 1.25rem;
  font-weight: 700;
  z-index: 100;
}

.skip-link:focus {
  left: 0;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

/* ---- Header ---- */
header {
  border-bottom: 1px solid var(--border);
}

.header-inner {
  max-width: 68rem;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.15rem;
}

.brand img {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 0.5rem;
}

nav[aria-label="Main"] {
  margin-left: auto;
}

nav[aria-label="Main"] ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav[aria-label="Main"] a {
  display: block;
  padding: 0.5rem 0.85rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  border-radius: 0.45rem;
  transition: background-color 0.25s ease, color 0.25s ease;
}

nav[aria-label="Main"] a:hover,
nav[aria-label="Main"] a:focus {
  background-color: var(--panel);
  color: var(--accent);
}

.nav-cta {
  background-color: var(--accent);
  color: var(--bg) !important;
}

.nav-cta:hover,
.nav-cta:focus {
  background-color: #a8d8ff;
  color: var(--bg) !important;
}

/* ---- Main ---- */
main {
  flex: 1;
  width: 100%;
  max-width: 68rem;
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
}

h1 {
  font-size: 2.4rem;
  line-height: 1.15;
  margin: 0 0 1rem;
  max-width: 20ch;
}

h2 {
  font-size: 1.6rem;
  margin-top: 3rem;
}

h3 {
  font-size: 1.1rem;
  margin-bottom: 0.4rem;
}

a {
  color: var(--accent);
}

.lede {
  color: var(--muted);
  font-size: 1.1rem;
  max-width: 58ch;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.09em;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0;
}

/* ---- Hero ---- */
.hero {
  position: relative;
  border-radius: 1rem;
  overflow: hidden;
  margin-bottom: 1rem;
}

.hero img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-overlay {
  position: relative;
  min-height: 22rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.75rem;
  padding: 3rem 2rem;
  background-color: rgba(11, 18, 32, 0.86);
}

.hero-overlay p {
  color: var(--muted);
  max-width: 52ch;
  margin: 0;
}

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

.button {
  display: inline-block;
  padding: 0.8rem 1.6rem;
  border-radius: 0.55rem;
  background-color: var(--accent);
  color: var(--bg);
  text-decoration: none;
  font-weight: 700;
  transition: background-color 0.25s ease;
}

.button:hover,
.button:focus {
  background-color: #a8d8ff;
  color: var(--bg);
}

.button-ghost {
  background-color: transparent;
  color: var(--text);
  border: 2px solid var(--border);
}

.button-ghost:hover,
.button-ghost:focus {
  background-color: var(--panel);
  color: var(--accent);
}

/* ---- Feature and pricing grid ----
   Three columns on desktop collapsing to one on mobile with no extra
   markup, which is the whole reason this is a grid and not floats. */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin: 1.5rem 0;
}

.feature {
  background-color: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0.85rem;
  padding: 1.4rem;
}

.feature h3 {
  margin-top: 0;
  color: var(--accent);
}

.feature p {
  color: var(--muted);
  margin-bottom: 0;
}

.price {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text);
  margin: 0.25rem 0 0.75rem;
}

.price span {
  font-size: 0.95rem;
  font-weight: 400;
  color: var(--muted);
}

/* The featured tier is outlined AND labelled in its heading, so the
   distinction never depends on colour alone. */
.price-featured {
  border-color: var(--accent);
}

.checklist {
  padding-left: 1.15rem;
  margin: 0;
  color: var(--muted);
}

.checklist li {
  margin-bottom: 0.35rem;
}

/* ---- Interactive chart ---- */
.chart {
  display: flex;
  align-items: flex-end;
  gap: 0.6rem;
  height: 14rem;
  padding: 1rem;
  margin: 1rem 0 0.5rem;
  background-color: var(--panel);
  border: 1px solid var(--border);
  border-radius: 0.85rem;
}

.chart-bar {
  flex: 1;
  min-width: 0;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: 0 0 0.4rem;
  border: 0;
  border-radius: 0.4rem 0.4rem 0 0;
  background-color: var(--accent-deep);
  color: var(--bg);
  font: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.25s ease, transform 0.25s ease;
}

.chart-bar:hover,
.chart-bar:focus-visible,
.chart-bar.is-active {
  background-color: var(--accent);
  transform: translateY(-4px);
}

.chart-readout {
  color: var(--muted);
  font-weight: 600;
  min-height: 1.6rem;
}

/* ---- Form ---- */
fieldset {
  border: 1px solid var(--border);
  border-radius: 0.7rem;
  margin: 0 0 1.25rem;
  padding: 1.1rem 1.25rem 1.35rem;
}

legend {
  font-weight: 700;
  color: var(--accent);
  padding: 0 0.4rem;
}

.field {
  margin-bottom: 1rem;
}

.field label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.3rem;
}

input[type="text"],
input[type="email"],
select,
textarea {
  width: 100%;
  padding: 0.65rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background-color: var(--panel);
  color: var(--text);
  font: inherit;
}

.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.radio-group label,
.checkbox-field label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-weight: 400;
}

input[type="radio"],
input[type="checkbox"] {
  accent-color: var(--accent);
}

.required {
  color: var(--accent);
}

.field-error {
  display: block;
  color: #ffb4a8;
  font-weight: 600;
  font-size: 0.9rem;
  min-height: 1.1rem;
  margin-top: 0.25rem;
}

button[type="submit"] {
  padding: 0.8rem 1.75rem;
  border: 0;
  border-radius: 0.55rem;
  background-color: var(--accent);
  color: var(--bg);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.25s ease;
}

button[type="submit"]:hover,
button[type="submit"]:focus {
  background-color: #a8d8ff;
}

/* ---- Footer ---- */
footer {
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

.footer-inner {
  max-width: 68rem;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 1.5rem;
}

.footer-inner h2 {
  font-size: 1rem;
  margin-top: 0;
}

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

.footer-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-nav li {
  margin-bottom: 0.4rem;
}

.footer-bottom {
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 1rem 1.5rem;
  font-size: 0.87rem;
  color: var(--muted);
  margin: 0;
}

/* ==========================================================
   Responsive
   ========================================================== */

@media (max-width: 860px) {
  .feature-grid,
  .footer-inner {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  h1 {
    font-size: 1.85rem;
  }

  .feature-grid,
  .footer-inner {
    grid-template-columns: 1fr;
  }

  .hero-overlay {
    min-height: 18rem;
    padding: 2rem 1.5rem;
  }

  .chart {
    height: 11rem;
  }

  nav[aria-label="Main"] {
    margin-left: 0;
    width: 100%;
  }
}