:root {
  --bg: #ffffff;
  --soft: #f4f8f5;
  --ink: #10231c;
  --muted: #53635c;
  --green: #0f713a;
  --green-dark: #064326;
  --blue: #205ba8;
  --coral: #e8634d;
  --teal: #0f7c7a;
  --border: #dce7e1;
  --shadow: 0 18px 48px rgba(24, 48, 37, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
  overflow-x: hidden;
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 72px;
  padding: 0 clamp(20px, 5vw, 72px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--green-dark);
  font-size: 24px;
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: var(--green);
  color: #fff;
  font-size: 20px;
}

.nav {
  display: flex;
  gap: clamp(18px, 3vw, 38px);
  font-size: 15px;
  font-weight: 650;
}

.nav a {
  padding: 24px 0 21px;
  color: #17261f;
  text-decoration: none;
  border-bottom: 3px solid transparent;
}

.nav a:hover,
.nav a:focus {
  color: var(--green);
  border-color: var(--green);
}

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}

.menu-button span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

.section {
  padding: clamp(46px, 7vw, 92px) clamp(20px, 5vw, 72px);
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  align-items: center;
  min-height: 560px;
  overflow: hidden;
}

.hero::before {
  position: absolute;
  bottom: -140px;
  left: -80px;
  width: min(620px, 72vw);
  height: 330px;
  content: "";
  background:
    radial-gradient(circle at 22px 24px, rgba(18, 111, 54, .38) 2px, transparent 3px),
    linear-gradient(135deg, rgba(143, 203, 98, .8), rgba(219, 244, 205, .7));
  background-size: 54px 54px, auto;
  border-top-right-radius: 100%;
  transform: rotate(3deg);
}

.hero-copy {
  position: relative;
  z-index: 1;
  max-width: 720px;
  min-width: 0;
}

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

h1 {
  margin-bottom: 22px;
  color: var(--green-dark);
  font-size: clamp(54px, 8vw, 104px);
  line-height: 0.96;
  letter-spacing: 0;
  overflow-wrap: anywhere;
}

.hero p {
  max-width: 700px;
  margin-bottom: 34px;
  color: #162821;
  font-size: clamp(21px, 2.2vw, 31px);
  line-height: 1.38;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 56px;
  min-width: 210px;
  padding: 0 24px;
  border: 2px solid var(--green);
  border-radius: 8px;
  font-size: 17px;
  font-weight: 800;
  text-decoration: none;
  box-shadow: 0 12px 24px rgba(15, 113, 58, .13);
}

.button svg {
  width: 25px;
  height: 25px;
  fill: currentColor;
}

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

.button.secondary {
  background: #fff;
  color: var(--blue);
  border-color: var(--blue);
}

.cards-section {
  background: linear-gradient(180deg, #fff 0, var(--soft) 100%);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 26px;
  min-width: 0;
}

h2 {
  margin-bottom: 8px;
  color: var(--green-dark);
  font-size: clamp(32px, 4.6vw, 48px);
  line-height: 1.08;
  letter-spacing: 0;
}

.section-heading p,
.lead {
  color: var(--muted);
  font-size: 18px;
}

.card-grid,
.example-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
}

.link-card {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 220px;
  padding: 22px;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  text-decoration: none;
  box-shadow: 0 12px 28px rgba(35, 59, 48, .08);
}

.link-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

.card-icon {
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  margin-bottom: 18px;
  border-radius: 8px;
  color: #fff;
}

.card-icon svg {
  width: 33px;
  height: 33px;
  fill: currentColor;
}

.green .card-icon { background: var(--green); }
.blue .card-icon { background: var(--blue); }
.coral .card-icon { background: var(--coral); }
.teal .card-icon { background: var(--teal); }

.card-title {
  margin-bottom: 10px;
  font-size: 20px;
  font-weight: 850;
  line-height: 1.18;
}

.card-text {
  color: var(--muted);
  font-size: 16px;
}

.arrow {
  margin-top: auto;
  align-self: flex-end;
  color: currentColor;
  font-size: 34px;
  line-height: 1;
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, .95fr) minmax(320px, 1.05fr);
  gap: clamp(28px, 6vw, 70px);
  align-items: center;
}

.domain-list {
  display: grid;
  gap: 12px;
  margin-top: 28px;
}

.domain-list div {
  display: grid;
  gap: 4px;
  padding: 16px 18px;
  background: #f7faf8;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.domain-list span {
  color: var(--green);
  font-weight: 800;
}

.browser-card {
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.browser-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 16px;
  background: #edf4f0;
  border-bottom: 1px solid var(--border);
}

.browser-bar span {
  width: 10px;
  height: 10px;
  background: #91a99d;
  border-radius: 50%;
}

.browser-bar p {
  margin: 0 0 0 8px;
  color: var(--muted);
  font-size: 14px;
}

.course-card {
  margin: 28px;
  padding: clamp(24px, 4vw, 42px);
  background:
    linear-gradient(rgba(255, 255, 255, .86), rgba(255, 255, 255, .86)),
    radial-gradient(circle at 20% 20%, #89c765 0 7%, transparent 8% 100%),
    radial-gradient(circle at 80% 70%, #98d3cc 0 8%, transparent 9% 100%),
    #f4faf6;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.course-card h3 {
  font-size: 34px;
  line-height: 1.05;
}

.course-card p {
  color: var(--muted);
  font-size: 18px;
}

.course-card button,
.course-button,
.reply-row button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 0;
  border-radius: 8px;
  background: var(--green);
  color: #fff;
  font-weight: 800;
  text-decoration: none;
}

.chatbot-section {
  background: var(--soft);
}

.bot-layout {
  display: grid;
  grid-template-columns: minmax(240px, 360px) minmax(0, 1fr);
  gap: 18px;
}

.bot-list {
  display: grid;
  gap: 10px;
}

.bot-item {
  display: grid;
  gap: 3px;
  width: 100%;
  padding: 18px;
  text-align: left;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--ink);
}

.bot-item span {
  font-size: 18px;
  font-weight: 850;
}

.bot-item small {
  color: var(--muted);
  font-size: 14px;
}

.bot-item.active {
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(32, 91, 168, .12);
}

.chat-preview {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-height: 360px;
  padding: clamp(20px, 4vw, 34px);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 12px 28px rgba(35, 59, 48, .08);
}

.chat-title {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.chat-title strong {
  font-size: 22px;
}

.chat-title span {
  color: var(--muted);
  font-size: 14px;
}

.message {
  max-width: 72%;
  padding: 14px 16px;
  border-radius: 8px;
}

.message.student {
  align-self: flex-end;
  background: var(--blue);
  color: #fff;
}

.message.bot {
  background: #eef6f1;
}

.reply-row {
  display: flex;
  gap: 10px;
  margin-top: auto;
}

.reply-row input {
  flex: 1;
  min-width: 0;
  min-height: 44px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--ink);
  font: inherit;
}

.examples-section {
  background: #fff;
}

.page-hero {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 28px;
  min-height: 360px;
}

.page-hero h1 {
  max-width: 900px;
  margin-bottom: 14px;
  font-size: clamp(44px, 7vw, 88px);
}

.subdomain-note {
  flex: 0 0 auto;
  max-width: 360px;
  padding: 16px 18px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--green-dark);
  font-weight: 850;
  box-shadow: 0 12px 28px rgba(35, 59, 48, .08);
}

.resources-hero {
  background:
    radial-gradient(circle at 88% 18%, rgba(232, 99, 77, .16), transparent 26%),
    var(--soft);
}

.help-hero {
  background:
    radial-gradient(circle at 86% 16%, rgba(15, 124, 122, .16), transparent 28%),
    #fff;
}

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

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

.example-grid article {
  min-height: 165px;
  padding: 22px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 12px 28px rgba(35, 59, 48, .08);
}

.example-grid h3 {
  color: var(--green-dark);
  font-size: 22px;
}

.example-grid p,
.footer p {
  color: var(--muted);
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 28px clamp(20px, 5vw, 72px);
  border-top: 1px solid var(--border);
}

.footer p {
  margin: 0;
}

.footer a {
  color: var(--green);
  font-weight: 800;
  text-decoration: none;
}

@media (max-width: 980px) {
  .hero,
  .split-section,
  .bot-layout {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding-top: 54px;
  }

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

@media (max-width: 700px) {
  .site-header {
    min-height: 64px;
    padding: 0 16px;
  }

  .brand {
    font-size: 20px;
  }

  .nav {
    position: absolute;
    top: 64px;
    right: 16px;
    left: 16px;
    display: none;
    grid-template-columns: 1fr;
    gap: 0;
    padding: 8px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 8px;
    box-shadow: var(--shadow);
  }

  .nav.open {
    display: grid;
  }

  .nav a {
    padding: 12px;
    border: 0;
  }

  .menu-button {
    display: block;
  }

  .section {
    padding: 42px 16px;
    overflow: hidden;
  }

  .hero,
  .split-section,
  .bot-layout {
    grid-template-columns: minmax(0, 1fr);
  }

  h1 {
    font-size: clamp(38px, 13vw, 50px);
    line-height: 1;
  }

  .hero p {
    max-width: 32ch;
    font-size: 18px;
  }

  .section-heading p,
  .lead {
    max-width: 34ch;
  }

  .actions,
  .button,
  .reply-row,
  .footer {
    width: 100%;
  }

  .actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .button {
    min-width: 0;
    width: min(100%, 320px);
    max-width: 320px;
  }

  .card-grid,
  .example-grid {
    grid-template-columns: 1fr;
  }

  .link-card {
    min-height: 154px;
  }

  .chat-title,
  .page-hero,
  .reply-row,
  .footer {
    flex-direction: column;
    align-items: stretch;
  }

  .message {
    max-width: 92%;
  }
}