:root {
  --dark: #08131f;
  --dark-2: #0b1724;
  --dark-3: #101d2b;
  --text: #101725;
  --muted: #647083;
  --line: #e5ebf2;
  --soft: #f5f8fb;
  --surface: #ffffff;
  --green: #16c79a;
  --green-dark: #0aa87f;
  --cyan: #29d7e8;
  --blue: #1688d3;
  --purple: #7c55f4;
  --orange: #ff7144;
  --shadow: 0 22px 55px rgba(20, 36, 56, 0.13);
  color-scheme: light;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  letter-spacing: 0;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  overflow-x: hidden;
  background: var(--soft);
  color: var(--text);
  font-size: 16px;
  line-height: 1.55;
}

p,
h1,
h2,
h3 {
  overflow-wrap: break-word;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
textarea,
select {
  font: inherit;
  letter-spacing: 0;
}

.site-header {
  position: fixed;
  z-index: 20;
  top: 0;
  left: 0;
  right: 0;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 32px;
  min-height: 82px;
  padding: 16px 56px;
  color: #fff;
  transition:
    background 180ms ease,
    box-shadow 180ms ease,
    min-height 180ms ease;
}

.site-header.is-scrolled {
  min-height: 70px;
  background: rgba(8, 19, 31, 0.88);
  box-shadow: 0 16px 42px rgba(3, 9, 16, 0.28);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  width: fit-content;
  font-size: 1.55rem;
  font-weight: 820;
}

.brand-mark {
  position: relative;
  width: 38px;
  height: 38px;
  border: 4px solid var(--green);
  clip-path: polygon(25% 4%, 75% 4%, 100% 50%, 75% 96%, 25% 96%, 0 50%);
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 8px;
  border: 3px solid rgba(41, 215, 232, 0.8);
  clip-path: inherit;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 34px;
}

.site-nav a {
  position: relative;
  padding: 8px 0;
  color: rgba(255, 255, 255, 0.92);
  font-size: 0.98rem;
  font-weight: 560;
}

.site-nav a:hover,
.site-nav a.is-active {
  color: var(--green);
}

.site-nav a.is-active::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -10px;
  width: 48px;
  height: 2px;
  border-radius: 99px;
  background: var(--green);
  transform: translateX(-50%);
}

.header-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 14px;
  min-width: 0;
}

.login-action,
.signup-action,
.primary-action,
.secondary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  border-radius: 8px;
  padding: 13px 24px;
  font-weight: 720;
  white-space: nowrap;
}

.login-action,
.secondary-action {
  border: 1px solid rgba(255, 255, 255, 0.16);
  background: rgba(255, 255, 255, 0.03);
  color: #fff;
}

.signup-action,
.primary-action {
  border: 1px solid rgba(22, 199, 154, 0.3);
  background: linear-gradient(135deg, #16c79a 0%, #06b889 100%);
  color: #fff;
  box-shadow: 0 18px 36px rgba(22, 199, 154, 0.22);
}

.hero {
  position: relative;
  min-height: 710px;
  overflow: hidden;
  background:
    radial-gradient(circle at 76% 20%, rgba(41, 215, 232, 0.16), transparent 34%),
    radial-gradient(circle at 25% 12%, rgba(22, 199, 154, 0.1), transparent 30%),
    linear-gradient(135deg, #08131f 0%, #0b1724 54%, #0a1420 100%);
  color: #fff;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(rgba(255, 255, 255, 0.028) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.028) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, 0.5) 54%, transparent 100%);
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(540px, 1.14fr);
  align-items: center;
  gap: 46px;
  width: calc(100% - 112px);
  max-width: 1430px;
  margin: 0 auto;
  padding: 138px 0 116px;
}

.hero-copy {
  min-width: 0;
  max-width: 620px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 18px;
  color: var(--green);
  font-weight: 720;
}

.hero h1 {
  margin: 0;
  font-size: 3.45rem;
  line-height: 1.13;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 600px;
  margin: 26px 0 0;
  color: rgba(255, 255, 255, 0.72);
  font-size: 1.08rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 34px;
}

.primary-action,
.secondary-action {
  min-width: 198px;
}

.hero-visual {
  position: relative;
  min-width: 0;
}

.hero-visual img {
  display: block;
  width: min(100%, 820px);
  margin-left: auto;
  mask-image: radial-gradient(ellipse at 58% 52%, #000 0%, #000 58%, rgba(0, 0, 0, 0.72) 70%, transparent 88%);
  filter: drop-shadow(0 28px 48px rgba(0, 0, 0, 0.3));
}

.visual-label {
  position: absolute;
  color: rgba(255, 255, 255, 0.88);
  font-size: 0.95rem;
  font-weight: 720;
  text-shadow: 0 2px 14px rgba(0, 0, 0, 0.55);
}

.label-code {
  top: 31%;
  left: 24%;
}

.label-containers {
  top: 24%;
  left: 51%;
}

.label-cloud {
  top: 33%;
  right: 8%;
}

.label-automation {
  left: 18%;
  bottom: 24%;
}

.label-security {
  left: 45%;
  bottom: 17%;
}

.label-monitoring {
  right: 8%;
  bottom: 23%;
}

.feature-shell {
  position: relative;
  z-index: 2;
  width: calc(100% - 96px);
  max-width: 1440px;
  margin: -56px auto 0;
  border-radius: 16px;
  background: #fff;
  box-shadow: var(--shadow);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  padding: 34px;
}

.feature-item {
  display: grid;
  grid-template-columns: 60px 1fr;
  align-items: start;
  gap: 22px;
  min-width: 0;
}

.feature-icon {
  position: relative;
  display: grid;
  width: 60px;
  height: 60px;
  place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(22, 199, 154, 0.13), rgba(41, 215, 232, 0.08));
}

.feature-icon::before,
.feature-icon::after,
.course-icon::before,
.course-icon::after {
  content: "";
  position: absolute;
  display: block;
}

.icon-book::before {
  width: 25px;
  height: 30px;
  border: 3px solid var(--green-dark);
  border-radius: 4px;
}

.icon-book::after {
  top: 16px;
  width: 3px;
  height: 28px;
  background: var(--green-dark);
}

.icon-terminal::before {
  width: 30px;
  height: 22px;
  border: 3px solid var(--green-dark);
  border-radius: 4px;
}

.icon-terminal::after {
  width: 14px;
  height: 3px;
  background: var(--green-dark);
  transform: translate(6px, 6px);
}

.icon-progress::before {
  width: 30px;
  height: 30px;
  border-left: 3px solid var(--green-dark);
  border-bottom: 3px solid var(--green-dark);
}

.icon-progress::after {
  width: 25px;
  height: 15px;
  border-top: 3px solid var(--green-dark);
  border-right: 3px solid var(--green-dark);
  transform: rotate(-20deg);
}

.icon-community::before {
  width: 28px;
  height: 18px;
  border: 3px solid var(--green-dark);
  border-top: 0;
  border-radius: 0 0 12px 12px;
}

.icon-community::after {
  top: 17px;
  width: 12px;
  height: 12px;
  border: 3px solid var(--green-dark);
  border-radius: 50%;
}

.feature-item h2 {
  margin: 0 0 6px;
  color: var(--text);
  font-size: 1.02rem;
  line-height: 1.25;
}

.feature-item p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.section {
  padding: 72px 0;
}

.section-inner {
  width: calc(100% - 128px);
  max-width: 1400px;
  margin: 0 auto;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 28px;
  margin-bottom: 24px;
}

.section-heading h2,
.practice-layout h2,
.community-panel h2,
.about-grid h2 {
  margin: 0;
  color: var(--text);
  font-size: 1.7rem;
  line-height: 1.18;
}

.section-heading p,
.practice-layout p,
.community-panel p,
.about-grid p {
  margin: 8px 0 0;
  color: var(--muted);
}

.section-link {
  color: var(--green-dark);
  font-weight: 720;
}

.section-link::after {
  content: " ->";
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 22px;
}

.filter-button {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 9px 15px;
  background: #fff;
  color: var(--muted);
  cursor: pointer;
  font-weight: 700;
}

.filter-button.is-active {
  border-color: rgba(22, 199, 154, 0.28);
  background: rgba(22, 199, 154, 0.1);
  color: var(--green-dark);
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 20px;
}

.course-card {
  position: relative;
  display: flex;
  min-height: 228px;
  min-width: 0;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 28px 22px 22px;
  background: #fff;
  box-shadow: 0 18px 40px rgba(20, 36, 56, 0.08);
  transition:
    transform 160ms ease,
    box-shadow 160ms ease,
    border-color 160ms ease;
}

.course-card:hover {
  transform: translateY(-4px);
  border-color: rgba(22, 199, 154, 0.24);
  box-shadow: 0 24px 54px rgba(20, 36, 56, 0.14);
}

.course-card.is-hidden {
  display: none;
}

.course-number {
  color: var(--green-dark);
  font-size: 0.86rem;
  font-weight: 800;
}

.course-icon {
  position: absolute;
  top: 26px;
  left: 50%;
  display: block;
  width: 48px;
  height: 48px;
  transform: translateX(-50%);
}

.linux-icon::before {
  inset: 8px 14px 7px;
  border-radius: 45% 45% 38% 38%;
  background: #111827;
}

.linux-icon::after {
  left: 16px;
  bottom: 3px;
  width: 18px;
  height: 12px;
  border-radius: 50%;
  background: #f8c76c;
}

.git-icon {
  transform: translateX(-50%) rotate(45deg);
}

.git-icon::before {
  inset: 7px;
  border-radius: 6px;
  background: var(--orange);
}

.git-icon::after {
  top: 14px;
  left: 14px;
  width: 21px;
  height: 21px;
  border-top: 4px solid #fff;
  border-left: 4px solid #fff;
}

.docker-icon::before {
  left: 7px;
  bottom: 10px;
  width: 34px;
  height: 18px;
  border-radius: 4px 4px 14px 14px;
  background: #1e9ee9;
}

.docker-icon::after {
  left: 13px;
  top: 11px;
  width: 7px;
  height: 7px;
  box-shadow:
    9px 0 #1e9ee9,
    18px 0 #1e9ee9,
    0 9px #1e9ee9,
    9px 9px #1e9ee9,
    18px 9px #1e9ee9;
  background: #1e9ee9;
}

.cicd-icon::before {
  inset: 7px;
  border: 8px solid var(--purple);
  border-left-color: transparent;
  border-radius: 50%;
}

.cicd-icon::after {
  top: 9px;
  right: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--purple);
}

.cloud-icon::before {
  left: 8px;
  bottom: 12px;
  width: 34px;
  height: 20px;
  border: 3px solid var(--blue);
  border-radius: 18px;
}

.cloud-icon::after {
  left: 17px;
  top: 12px;
  width: 18px;
  height: 18px;
  border: 3px solid var(--blue);
  border-bottom: 0;
  border-radius: 50% 50% 0 0;
  background: #fff;
}

.course-card h3 {
  margin: 76px 0 8px;
  font-size: 1.08rem;
  line-height: 1.24;
}

.course-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.progress-row {
  display: grid;
  gap: 8px;
  margin-top: auto;
  padding-top: 22px;
  color: var(--muted);
  font-size: 0.9rem;
}

.progress-bar {
  display: block;
  height: 7px;
  overflow: hidden;
  border-radius: 999px;
  background: #edf1f5;
}

.progress-bar span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--green);
}

.practice-section,
.about-section {
  background: #fff;
}

.practice-layout,
.about-grid,
.community-panel {
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(420px, 1fr);
  gap: 46px;
  align-items: start;
}

.lab-list,
.about-points {
  display: grid;
  gap: 14px;
}

.lab-list article,
.about-points div,
.community-panel {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  box-shadow: 0 16px 34px rgba(20, 36, 56, 0.08);
}

.lab-list article {
  padding: 20px;
}

.lab-list span,
.about-points span,
.section-kicker {
  color: var(--green-dark);
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
}

.lab-list h3 {
  margin: 8px 0 8px;
  font-size: 1.04rem;
}

.lab-list p {
  margin: 0;
}

.community-panel {
  align-items: center;
  padding: 34px;
  background:
    radial-gradient(circle at 85% 20%, rgba(22, 199, 154, 0.12), transparent 28%),
    #fff;
}

.about-points div {
  padding: 22px;
}

.about-points strong {
  display: block;
  margin-top: 8px;
  color: var(--text);
}

@media (max-width: 1160px) {
  .site-header {
    grid-template-columns: auto 1fr;
  }

  .site-nav {
    display: none;
  }

  .hero-inner,
  .practice-layout,
  .about-grid,
  .community-panel {
    grid-template-columns: 1fr;
  }

  .hero-visual img {
    margin: 0 auto;
  }

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

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

@media (max-width: 760px) {
  .site-header {
    grid-template-columns: 1fr auto;
    gap: 12px;
    min-height: 68px;
    padding: 14px 18px;
  }

  .brand {
    font-size: 1.16rem;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
    border-width: 3px;
  }

  .header-actions {
    gap: 8px;
  }

  .login-action,
  .signup-action {
    min-height: 40px;
    padding: 9px 11px;
    font-size: 0.86rem;
  }

  .login-action {
    display: none;
  }

  .hero {
    min-height: auto;
  }

  .hero-inner,
  .section-inner {
    width: calc(100% - 28px);
  }

  .hero-inner {
    gap: 26px;
    padding: 104px 0 92px;
  }

  .hero h1 {
    font-size: 2.45rem;
    line-height: 1.14;
  }

  .hero-lead {
    font-size: 1rem;
  }

  .hero-actions {
    margin-top: 26px;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
    min-height: 48px;
  }

  .hero-visual img {
    width: 100%;
    max-width: 100%;
    margin: 0 auto;
    mask-image: radial-gradient(ellipse at 55% 52%, #000 0%, #000 64%, transparent 90%);
  }

  .visual-label {
    display: none;
  }

  .feature-shell {
    width: calc(100% - 28px);
    margin-top: -52px;
    border-radius: 14px;
  }

  .feature-grid {
    grid-template-columns: 1fr;
    padding: 22px;
  }

  .section {
    padding: 54px 0;
  }

  .section-heading {
    align-items: stretch;
    flex-direction: column;
  }

  .course-grid {
    grid-template-columns: 1fr;
  }

  .practice-layout,
  .about-grid,
  .community-panel {
    gap: 24px;
  }

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