@import url("https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;700;800&display=swap");

:root {
  --background-color: #0d1621;
  --background-second-color: #17212b;
  --background-third-color: #111d28;
  --background-chat-bot-color: #1c3043;
  --button-color: #2398e6;
  --button-hover-color: #35a7f4;
  --separator-color: #1d2f43;
  --text-color: #ffffff;
  --text-hint-color: #9dabb8;
  --accent-color: #2398e6;
  --star-color: #ffbe2b;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 34px;
}

body {
  margin: 0;
  background: var(--background-color);
  color: var(--text-color);
  font-family: "Manrope", Arial, sans-serif;
  font-size: 18px;
  font-weight: 400;
  line-height: 1.7;
}

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

a:hover {
  color: var(--button-hover-color);
}

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

h1,
h2,
h3,
p {
  margin: 0;
}

h1,
h2,
h3 {
  line-height: 1.35;
  font-weight: 800;
}

h1 {
  font-size: 42px;
  text-transform: uppercase;
}

h2 {
  font-size: 30px;
  text-transform: uppercase;
}

h3 {
  font-size: 22px;
}

strong {
  font-weight: 800;
}

.mid {
  position: relative;
  max-width: 1175px;
  margin: 0 auto;
  padding-right: 15px;
  padding-left: 15px;
}

.button {
  display: inline-flex;
  min-height: 56px;
  align-items: center;
  justify-content: center;
  padding: 0 32px;
  border-radius: 50px;
  background: var(--button-color);
  color: #fff;
  font-weight: 800;
  line-height: 1.1;
  text-align: center;
  transition: background 0.15s ease;
}

.button:hover {
  background: var(--button-hover-color);
  color: #fff;
}

.button-secondary {
  border: 1px solid var(--separator-color);
  background: var(--background-second-color);
}

.button-secondary:hover {
  background: var(--background-third-color);
}

.header {
  position: relative;
  z-index: 50;
  padding: 20px 0;
  margin-bottom: 50px;
}

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

.header-logo {
  display: block;
  width: 34px;
  color: #fff;
}

.header-logo:hover,
.header-logo:focus {
  color: #fff;
}

.header-logo path {
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 66.67px;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 22px;
}

.header-nav-item {
  color: var(--text-color);
  font-size: 16px;
  font-weight: 600;
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  border: 1px solid var(--separator-color);
  border-radius: 12px;
  background: var(--background-second-color);
  color: var(--text-color);
  cursor: pointer;
}

.menu-toggle span {
  width: 18px;
  height: 2px;
  border-radius: 5px;
  background: currentColor;
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.header.menu-open .menu-toggle span:first-child {
  transform: translateY(7px) rotate(45deg);
}

.header.menu-open .menu-toggle span:nth-child(2) {
  opacity: 0;
}

.header.menu-open .menu-toggle span:last-child {
  transform: translateY(-7px) rotate(-45deg);
}

.home,
.review,
.features,
.examples,
.start,
.about,
.faq {
  margin-bottom: 90px;
}

.home-title {
  max-width: 850px;
  margin: 0 auto 26px;
  text-align: center;
}

.home-description {
  max-width: 760px;
  margin: 0 auto 30px;
  color: #d9e1ea;
  text-align: center;
}

.home-button {
  text-align: center;
}

[id] {
  scroll-margin-top: 34px;
}

.title {
  margin-bottom: 40px;
}

.title-main {
  text-align: center;
}

.review-items {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
}

.review-item,
.feature-item,
.example-chat {
  background: var(--background-second-color);
  border: 1px solid rgba(255, 255, 255, 0.03);
  border-radius: 15px;
  box-shadow: 0 7px 15px rgba(0, 0, 0, 0.08);
}

.review-item {
  width: calc(33.333% - 10px);
  padding: 22px;
}

.review-title {
  margin-bottom: 10px;
  font-size: 21px;
  font-weight: 800;
}

.review-stars {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
  color: var(--star-color);
  font-size: 19px;
  line-height: 1;
}

.review-description,
.feature-item p,
.start-description,
.text p,
.text li,
.faq-items p {
  color: #d2dbe4;
}

.feature-items,
.example-chats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 15px;
}

.feature-item {
  padding: 24px;
}

.feature-item h3 {
  margin-bottom: 12px;
}

.example-chat {
  display: grid;
  gap: 12px;
  padding: 20px;
}

.chat-message {
  max-width: 88%;
  padding: 13px 16px;
  border-radius: 18px;
  font-size: 16px;
  line-height: 1.55;
}

.chat-user {
  justify-self: end;
  border-bottom-right-radius: 6px;
  background: var(--button-color);
  color: #fff;
}

.chat-bot {
  justify-self: start;
  border-bottom-left-radius: 6px;
  background: var(--background-chat-bot-color);
  color: #d2dbe4;
}

.scroll-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 80;
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 50%;
  background: var(--background-second-color);
  color: #fff;
  box-shadow: none;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition: opacity 0.15s ease, transform 0.15s ease, background 0.15s ease;
}

.scroll-top:hover {
  background: var(--background-chat-bot-color);
}

.scroll-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.scroll-top span {
  width: 13px;
  height: 13px;
  margin-top: 5px;
  border-top: 3px solid currentColor;
  border-left: 3px solid currentColor;
  transform: rotate(45deg);
}

.start {
  padding: 46px 0;
  background: var(--background-second-color);
  text-align: center;
}

.start-title {
  margin-bottom: 15px;
}

.start-description {
  max-width: 720px;
  margin: 0 auto 24px;
}

.text {
  max-width: 900px;
  margin: 0 auto 42px;
}

.text:last-child {
  margin-bottom: 0;
}

.text h2 {
  margin-bottom: 18px;
}

.text p {
  margin-bottom: 18px;
}

.text ol {
  display: grid;
  gap: 12px;
  margin: 22px 0 0;
  padding-left: 28px;
}

.faq-items {
  display: grid;
  max-width: 900px;
  margin: 0 auto;
  gap: 12px;
}

details {
  overflow: hidden;
  border: 1px solid var(--separator-color);
  border-radius: 15px;
  background: var(--background-second-color);
}

summary {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  cursor: pointer;
  list-style: none;
  padding: 20px 22px;
  font-weight: 800;
}

summary::before {
  content: "";
  flex: 0 0 auto;
  width: 0;
  height: 0;
  margin-top: 9px;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 7px solid var(--text-hint-color);
  transition: transform 0.15s ease;
}

summary::-webkit-details-marker {
  display: none;
}

details[open] summary::before {
  transform: rotate(90deg);
}

details p {
  padding: 0 22px 22px;
}

.footer {
  padding: 40px 0;
  border-top: 1px solid var(--separator-color);
}

.footer-copyright {
  color: var(--text-hint-color);
  font-size: 14px;
  text-align: center;
}

.error-page {
  display: flex;
  min-height: calc(100vh - 105px);
  align-items: center;
  margin-bottom: 90px;
}

.error-content {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
}

.error-content h1 {
  margin-bottom: 18px;
}

.error-content p {
  max-width: 650px;
  margin: 0 auto 28px;
  color: #d2dbe4;
}

.error-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

@media (max-width: 992px) {
  body {
    font-size: 16px;
  }

  .review-item {
    width: 100%;
  }

  .feature-items,
  .example-chats {
    grid-template-columns: 1fr;
  }

  .home,
  .review,
  .features,
  .examples,
  .start,
  .about,
  .faq {
    margin-bottom: 70px;
  }
}

@media (max-width: 768px) {
  h1 {
    font-size: 36px;
  }

  h2 {
    font-size: 24px;
  }

  h3 {
    font-size: 21px;
  }

  .header-nav {
    gap: 14px;
  }

  .header-nav-item {
    font-size: 14px;
  }

  .title {
    margin-bottom: 28px;
  }
}

@media (max-width: 520px) {
  .header {
    margin-bottom: 25px;
  }

  .header-items {
    align-items: flex-start;
  }

  .menu-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .header-nav {
    position: absolute;
    top: 52px;
    right: 15px;
    z-index: 100;
    display: grid;
    min-width: 190px;
    gap: 0;
    padding: 8px;
    border: 1px solid var(--separator-color);
    border-radius: 15px;
    background: #17212b;
    box-shadow: 0 14px 35px rgba(0, 0, 0, 0.24);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-8px);
    visibility: hidden;
    transition: opacity 0.15s ease, transform 0.15s ease, visibility 0.15s ease;
  }

  .header.menu-open .header-nav {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
    visibility: visible;
  }

  .header-nav-item {
    padding: 11px 12px;
    border-radius: 10px;
    font-size: 15px;
  }

  .header-nav-item:hover {
    background: var(--background-third-color);
  }

  h1 {
    font-size: 28px;
  }

  h2 {
    font-size: 23px;
  }

  .home,
  .review,
  .features,
  .examples,
  .about,
  .faq {
    margin-bottom: 45px;
  }

  .start {
    margin-bottom: 50px;
  }

  .button {
    width: 100%;
  }

  .chat-message {
    max-width: 94%;
  }

  .error-page {
    min-height: calc(100vh - 95px);
    margin-bottom: 50px;
  }

  .error-actions {
    display: grid;
  }
}