/*
  Design system for chatagi.ru — «Чат AGI»
  Аудитория: русскоязычные пользователи, которые хотят понять и применять ИИ-чат в работе,
  обучении, текстах, анализе и принятии решений без завышенных обещаний.
  Стиль бренда: технологичный, спокойный, экспертный, дружелюбный.
  Визуальная концепция: тёмная нейросетевая среда, стеклянные карточки, мягкие градиенты,
  акцентные линии и «лабораторные» элементы интерфейса.
  Шрифтовая пара: Inter/Manrope/system для текста, JetBrains Mono/monospace для промптов и терминов.
*/

:root {
  --font-main: Inter, Manrope, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  --font-code: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;

  --color-bg: #07111f;
  --color-bg-deep: #030712;
  --color-bg-soft: #0d1a30;
  --color-surface: rgba(15, 28, 52, 0.78);
  --color-surface-strong: rgba(20, 37, 68, 0.96);
  --color-card: rgba(255, 255, 255, 0.055);
  --color-card-hover: rgba(255, 255, 255, 0.085);
  --color-text: #eef5ff;
  --color-muted: #a9b7cc;
  --color-subtle: #74839b;
  --color-heading: #ffffff;
  --color-primary: #58e6ff;
  --color-primary-dark: #16b7d7;
  --color-primary-soft: rgba(88, 230, 255, 0.14);
  --color-accent: #9b6cff;
  --color-accent-soft: rgba(155, 108, 255, 0.17);
  --color-positive: #b6ff6a;
  --color-warning: #ffd166;
  --color-line: rgba(174, 206, 255, 0.18);
  --color-link: #77edff;
  --color-link-hover: #b6ff6a;

  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 26px;
  --radius-xl: 34px;
  --shadow-soft: 0 22px 70px rgba(0, 0, 0, 0.35);
  --shadow-glow: 0 0 42px rgba(88, 230, 255, 0.16);
  --container: 1160px;
  --section-gap: clamp(64px, 8vw, 108px);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-main);
  font-size: 17px;
  line-height: 1.7;
  color: var(--color-text);
  background:
    radial-gradient(circle at 18% 5%, rgba(88, 230, 255, 0.18), transparent 33%),
    radial-gradient(circle at 88% 16%, rgba(155, 108, 255, 0.18), transparent 34%),
    linear-gradient(135deg, var(--color-bg-deep), var(--color-bg) 52%, #0b1530);
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.025) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.8), transparent 90%);
}

body::after {
  content: "";
  position: fixed;
  inset: auto 8% 0 auto;
  width: 290px;
  height: 290px;
  z-index: -1;
  pointer-events: none;
  border-radius: 999px;
  background: rgba(182, 255, 106, 0.09);
  filter: blur(74px);
}

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

svg {
  display: block;
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

a:hover,
a:focus-visible {
  color: var(--color-link-hover);
}

:focus-visible {
  outline: 3px solid rgba(182, 255, 106, 0.8);
  outline-offset: 4px;
}

.container {
  width: min(100% - 36px, var(--container));
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  left: 18px;
  top: -80px;
  z-index: 50;
  padding: 10px 16px;
  color: #05101d;
  background: var(--color-positive);
  border-radius: 999px;
  font-weight: 800;
}

.skip-link:focus {
  top: 18px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--color-line);
  background: rgba(3, 7, 18, 0.78);
  backdrop-filter: blur(18px);
}

.header-inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--color-heading);
  font-weight: 900;
  letter-spacing: -0.04em;
}

.logo-mark {
  width: 38px;
  height: 38px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  color: #03101a;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent) 64%, var(--color-positive));
  box-shadow: var(--shadow-glow);
  font-family: var(--font-code);
  font-size: 15px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.main-nav a {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 750;
  padding: 9px 12px;
  border-radius: 999px;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--color-heading);
  background: rgba(255, 255, 255, 0.075);
}

.hero,
.page-hero {
  padding: clamp(64px, 8vw, 112px) 0 clamp(42px, 5vw, 72px);
}

.hero-grid,
.page-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.07fr) minmax(320px, 0.93fr);
  gap: clamp(32px, 5vw, 72px);
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  color: var(--color-positive);
  font-size: 13px;
  line-height: 1.3;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 8px 12px;
  border: 1px solid rgba(182, 255, 106, 0.22);
  border-radius: 999px;
  background: rgba(182, 255, 106, 0.08);
}

.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: currentColor;
  box-shadow: 0 0 18px currentColor;
}

h1,
h2,
h3 {
  color: var(--color-heading);
  line-height: 1.06;
  margin: 0;
  letter-spacing: -0.045em;
}

h1 {
  font-size: clamp(42px, 7vw, 78px);
  margin-top: 22px;
}

h2 {
  font-size: clamp(30px, 4.4vw, 50px);
}

h3 {
  font-size: clamp(21px, 2.4vw, 28px);
}

p {
  margin: 0;
}

.lead {
  max-width: 700px;
  color: var(--color-muted);
  font-size: clamp(18px, 2.2vw, 22px);
  margin-top: 22px;
}

.text-muted {
  color: var(--color-muted);
}

.hero-actions,
.cta-actions,
.inline-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 30px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 12px 18px;
  border-radius: 999px;
  font-weight: 850;
  border: 1px solid transparent;
  box-shadow: none;
}

.btn-primary {
  color: #03101a;
  background: linear-gradient(135deg, var(--color-primary), #8ff4ff 48%, var(--color-positive));
  box-shadow: 0 16px 50px rgba(88, 230, 255, 0.18);
}

.btn-primary:hover {
  color: #03101a;
  transform: translateY(-2px);
}

.btn-secondary {
  color: var(--color-heading);
  background: rgba(255, 255, 255, 0.07);
  border-color: var(--color-line);
}

.btn-secondary:hover {
  color: var(--color-heading);
  background: rgba(255, 255, 255, 0.11);
  transform: translateY(-2px);
}

.hero-card,
.visual-card,
.section-panel,
.card,
.term-card,
.prompt-card,
.notice-card,
.cta-panel {
  border: 1px solid var(--color-line);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.075), rgba(255, 255, 255, 0.035));
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  backdrop-filter: blur(18px);
}

.hero-card,
.visual-card {
  position: relative;
  overflow: hidden;
  padding: clamp(18px, 3vw, 28px);
}

.hero-card::after,
.visual-card::after {
  content: "";
  position: absolute;
  inset: -36% -22% auto auto;
  width: 210px;
  height: 210px;
  border-radius: 999px;
  background: rgba(88, 230, 255, 0.14);
  filter: blur(52px);
}

.hero-card img,
.visual-card img {
  position: relative;
  z-index: 1;
  width: 100%;
  border-radius: var(--radius-md);
}

.status-strip {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 18px;
}

.status-item {
  padding: 12px;
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  background: rgba(3, 7, 18, 0.45);
  border: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 13px;
}

.status-item strong {
  display: block;
  color: var(--color-heading);
  font-size: 20px;
  line-height: 1.1;
}

section {
  padding: var(--section-gap) 0;
}

.section-tight {
  padding-top: 28px;
}

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(280px, 0.58fr);
  gap: 28px;
  align-items: end;
  margin-bottom: 34px;
}

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

.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: 18px;
}

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

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.card,
.term-card,
.prompt-card,
.notice-card {
  padding: clamp(20px, 2.5vw, 28px);
}

.card:hover,
.term-card:hover,
.prompt-card:hover {
  background: var(--color-card-hover);
}

.card-icon {
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  margin-bottom: 18px;
  border-radius: 16px;
  color: #03101a;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  font-weight: 900;
  font-family: var(--font-code);
}

.card h3,
.term-card h3,
.prompt-card h3,
.notice-card h3 {
  margin-bottom: 12px;
}

.card p,
.term-card p,
.prompt-card p,
.notice-card p,
.card li,
.notice-card li {
  color: var(--color-muted);
}

.card ul,
.notice-card ul,
.clean-list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.card li,
.notice-card li,
.clean-list li {
  position: relative;
  padding-left: 24px;
  margin-top: 10px;
}

.card li::before,
.notice-card li::before,
.clean-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--color-primary);
  box-shadow: 0 0 16px rgba(88, 230, 255, 0.45);
}

.section-panel {
  padding: clamp(24px, 4vw, 44px);
}

.split-panel {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(320px, 0.68fr);
  gap: clamp(24px, 4vw, 48px);
  align-items: center;
}

.kicker {
  color: var(--color-primary);
  font-family: var(--font-code);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.number-list {
  display: grid;
  gap: 14px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: steps;
}

.number-list li {
  position: relative;
  padding: 18px 18px 18px 62px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-muted);
  background: rgba(255, 255, 255, 0.045);
}

.number-list li::before {
  counter-increment: steps;
  content: counter(steps, decimal-leading-zero);
  position: absolute;
  left: 18px;
  top: 18px;
  color: var(--color-positive);
  font-family: var(--font-code);
  font-weight: 800;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.04);
}

table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
}

th,
td {
  padding: 18px;
  border-bottom: 1px solid var(--color-line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--color-heading);
  font-size: 14px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: rgba(255, 255, 255, 0.055);
}

td {
  color: var(--color-muted);
}

tr:last-child td {
  border-bottom: 0;
}

.prompt-card code,
.term-label,
.inline-code {
  font-family: var(--font-code);
  color: var(--color-positive);
}

.prompt-box {
  margin-top: 16px;
  padding: 16px;
  color: #dff9ff;
  background: rgba(3, 7, 18, 0.58);
  border: 1px solid rgba(88, 230, 255, 0.18);
  border-radius: var(--radius-md);
  font-family: var(--font-code);
  font-size: 14px;
  line-height: 1.65;
  white-space: pre-wrap;
}

.check-band {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.check-pill {
  padding: 16px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-muted);
  background: rgba(255, 255, 255, 0.045);
}

.check-pill strong {
  display: block;
  color: var(--color-heading);
  margin-bottom: 6px;
}

.cta-panel {
  position: relative;
  overflow: hidden;
  padding: clamp(28px, 5vw, 54px);
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) auto;
  gap: 24px;
  align-items: center;
}

.cta-panel::before {
  content: "";
  position: absolute;
  inset: auto -10% -65% auto;
  width: 360px;
  height: 360px;
  border-radius: 999px;
  background: rgba(155, 108, 255, 0.2);
  filter: blur(65px);
}

.cta-panel > * {
  position: relative;
  z-index: 1;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 18px;
  color: var(--color-subtle);
  font-size: 14px;
}

.breadcrumbs a {
  color: var(--color-muted);
}

.breadcrumbs span {
  color: var(--color-positive);
}

.footer {
  margin-top: var(--section-gap);
  padding: 40px 0;
  border-top: 1px solid var(--color-line);
  background: rgba(3, 7, 18, 0.44);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(240px, 0.9fr) minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.footer p,
.footer a {
  color: var(--color-muted);
  font-size: 14px;
}

.footer-links {
  display: flex;
  justify-content: flex-end;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-note {
  margin-top: 14px;
  color: var(--color-subtle);
  font-size: 13px;
}

@media (max-width: 980px) {
  .hero-grid,
  .page-hero-grid,
  .split-panel,
  .section-head,
  .cta-panel,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .grid-3,
  .grid-4,
  .check-band {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-links {
    justify-content: flex-start;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .container {
    width: min(100% - 28px, var(--container));
  }

  .header-inner {
    align-items: flex-start;
    flex-direction: column;
    padding: 14px 0;
  }

  .main-nav {
    justify-content: flex-start;
    width: 100%;
  }

  .main-nav a {
    padding: 8px 10px;
    font-size: 13px;
  }

  .hero,
  .page-hero {
    padding-top: 46px;
  }

  h1 {
    font-size: clamp(36px, 12vw, 54px);
  }

  .grid-2,
  .grid-3,
  .grid-4,
  .check-band,
  .status-strip {
    grid-template-columns: 1fr;
  }

  .hero-actions,
  .cta-actions,
  .inline-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .cta-panel {
    padding: 24px;
  }
}