:root {
  --bg: #05070d;
  --panel: rgba(10, 14, 24, 0.88);
  --panel-border: rgba(120, 0, 255, 0.35);
  --fg: #f2f6ff;
  --muted: #8b94b4;
  --accent: #7800ff;
  --accent-alt: #3f9dff;
  --danger: #ff4d73;
  font-family: "IBM Plex Mono", "Fira Mono", Consolas, "Courier New", monospace;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top, rgba(120, 0, 255, 0.12), transparent 55%),
    linear-gradient(180deg, rgba(5, 7, 13, 0.95), rgba(5, 7, 13, 0.99));
  color: var(--fg);
}

.scanlines {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(180deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 100% 3px;
  opacity: 0.4;
  mix-blend-mode: screen;
  z-index: 1;
}

.hero {
  position: relative;
  z-index: 2;
  display: grid;
  gap: clamp(2rem, 6vw, 4rem);
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  padding: clamp(2.4rem, 6vw, 4rem) clamp(1.6rem, 5vw, 5rem) 1rem;
  align-items: center;
}

.hero__content {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.hero__badge {
  align-self: flex-start;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  border: 1px solid rgba(120, 0, 255, 0.45);
  color: var(--accent-alt);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.75rem;
  text-decoration: none;
}

.hero__title {
  margin: 0;
  font-size: clamp(2.5rem, 7vw, 3.8rem);
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero__description {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.hero__list {
  margin: 0;
  padding-left: 1.2rem;
  color: var(--muted);
  line-height: 1.6;
}

.hero__cta {
  display: flex;
  gap: 0.8rem;
  flex-wrap: wrap;
}

.hero__cta .btn {
  text-decoration: none;
  padding: 0.85rem 1.4rem;
  border-radius: 999px;
  border: 1px solid rgba(120, 0, 255, 0.45);
  color: var(--fg);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  transition: background 0.2s ease, color 0.2s ease;
}

.hero__cta .btn:hover {
  background: rgba(63, 157, 255, 0.2);
  color: var(--accent-alt);
}

.stack {
  position: relative;
  z-index: 2;
  display: grid;
  gap: clamp(1.8rem, 4vw, 2.6rem);
  padding: 0 clamp(1.6rem, 5vw, 5rem) clamp(3rem, 8vw, 5rem);
}

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 1.4rem;
  padding: clamp(1.6rem, 4vw, 2.2rem);
  box-shadow: 0 32px 50px -38px rgba(120, 0, 255, 0.45);
}

.panel h2 {
  margin-top: 0;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.panel p,
.panel ul {
  color: var(--muted);
  line-height: 1.6;
}

.panel ul {
  margin: 0;
  padding-left: 1.2rem;
}

.snippet {
  position: relative;
  background: rgba(5, 7, 13, 0.82);
  border-radius: 1rem;
  border: 1px solid rgba(63, 157, 255, 0.35);
  padding: 1.2rem;
  overflow: auto;
  font-size: 0.92rem;
}

.snippet__loading {
  color: var(--muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.code-block {
  margin: 0;
  font-family: inherit;
  line-height: 1.65;
}

.code-line {
  display: flex;
  gap: 1rem;
  align-items: baseline;
  padding: 0.1rem 0.4rem;
  border-radius: 0.6rem;
  transition: background 0.2s ease, color 0.2s ease;
}

.code-line__number {
  min-width: 3ch;
  color: rgba(143, 155, 188, 0.75);
  text-align: right;
}

.code-line__code {
  white-space: pre;
}

.code-line.is-highlight {
  background: rgba(63, 157, 255, 0.22);
  color: var(--fg);
}

.review {
  display: grid;
  gap: 1rem;
}

.review__inputs {
  display: grid;
  gap: 0.8rem;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.review label {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.review input,
.review textarea {
  border-radius: 0.8rem;
  border: 1px solid rgba(120, 0, 255, 0.35);
  background: rgba(5, 7, 13, 0.72);
  color: var(--fg);
  padding: 0.8rem 1rem;
  font-size: 1rem;
  font-family: inherit;
}

.review textarea {
  min-height: 120px;
  resize: vertical;
}

.review__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.review button {
  padding: 0.85rem 1.6rem;
  border-radius: 999px;
  border: 1px solid rgba(120, 0, 255, 0.45);
  background: rgba(120, 0, 255, 0.22);
  color: var(--fg);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.review button:hover {
  background: rgba(63, 157, 255, 0.28);
  color: var(--accent-alt);
}

.review__result {
  border-radius: 0.8rem;
  border: 1px solid transparent;
  padding: 0.8rem 1rem;
  letter-spacing: 0.06em;
  font-size: 0.9rem;
}

.review__result.is-success {
  border-color: rgba(63, 157, 255, 0.45);
  background: rgba(63, 157, 255, 0.18);
  color: var(--fg);
}

.review__result.is-error {
  border-color: rgba(255, 77, 115, 0.45);
  background: rgba(255, 77, 115, 0.18);
  color: var(--danger);
}

.review__hint {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: -0.4rem;
}

.solution {
  display: grid;
  gap: 1.2rem;
}

.solution pre {
  background: rgba(5, 7, 13, 0.82);
  border: 1px solid rgba(63, 157, 255, 0.32);
  border-radius: 1rem;
  padding: 1.2rem;
  margin: 0;
  overflow: auto;
}

.solution__flag {
  margin: 0;
  font-size: 0.9rem;
  color: var(--accent-alt);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.panel--flag {
  grid-column: span 2;
}

.flag-form {
  display: grid;
  gap: 1rem;
}

.flag-form__field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.flag-form__field input {
  border-radius: 0.8rem;
  border: 1px solid rgba(120, 0, 255, 0.35);
  background: rgba(5, 7, 13, 0.72);
  color: var(--fg);
  padding: 0.85rem 1rem;
  font-size: 1rem;
}

.flag-form__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.flag-form__button {
  padding: 0.85rem 1.6rem;
  border-radius: 999px;
  border: 1px solid rgba(120, 0, 255, 0.45);
  background: rgba(120, 0, 255, 0.22);
  color: var(--fg);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.flag-form__button:hover {
  background: rgba(120, 0, 255, 0.32);
}

.flag-form__button--ghost {
  background: transparent;
  border-color: rgba(63, 157, 255, 0.45);
  color: var(--accent-alt);
}

.flag-form__button--ghost:hover {
  background: rgba(63, 157, 255, 0.18);
}

.flag-form__result {
  margin: 0;
  border-radius: 0.8rem;
  border: 1px solid transparent;
  padding: 0.8rem 1rem;
  font-size: 0.9rem;
  letter-spacing: 0.06em;
  display: none;
}

.flag-form__result.is-visible {
  display: block;
}

.flag-form__result.is-success {
  border-color: rgba(63, 157, 255, 0.45);
  background: rgba(63, 157, 255, 0.18);
  color: var(--fg);
}

.flag-form__result.is-error {
  border-color: rgba(255, 77, 115, 0.45);
  background: rgba(255, 77, 115, 0.18);
  color: var(--danger);
}

.flag-form--busy {
  opacity: 0.85;
}

.panel--theory {
  grid-column: span 2;
  display: grid;
  gap: 1rem;
}

.panel--theory details {
  background: rgba(5, 7, 13, 0.74);
  border: 1px solid rgba(120, 0, 255, 0.35);
  border-radius: 1rem;
  padding: 1.2rem 1.4rem;
  position: relative;
  overflow: hidden;
}

.panel--theory summary {
  cursor: pointer;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg);
  display: flex;
  align-items: center;
  gap: 0.8rem;
  list-style: none;
}

.panel--theory summary::-webkit-details-marker {
  display: none;
}

.panel--theory details[open] summary {
  color: var(--accent-alt);
}

.theory-content {
  margin-top: 1.2rem;
  display: grid;
  gap: 1.4rem;
  color: var(--muted);
  line-height: 1.65;
}

.theory-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.theory-card {
  background: rgba(8, 11, 19, 0.8);
  border: 1px solid rgba(63, 157, 255, 0.28);
  border-radius: 1rem;
  padding: 1rem 1.2rem;
  display: grid;
  gap: 0.6rem;
}

.theory-card h3 {
  margin: 0;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-alt);
  font-size: 0.95rem;
}

.theory-steps {
  display: grid;
  gap: 0.8rem;
}

.theory-step {
  display: grid;
  gap: 0.4rem;
  background: rgba(5, 7, 13, 0.75);
  border: 1px solid rgba(120, 0, 255, 0.22);
  border-radius: 0.9rem;
  padding: 0.9rem 1rem;
}

.theory-step strong {
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.theory-hint {
  margin: 0;
  font-size: 0.85rem;
  color: rgba(143, 155, 188, 0.85);
}

.theory-emphasis {
  background: rgba(63, 157, 255, 0.16);
  border: 1px solid rgba(63, 157, 255, 0.35);
  border-radius: 0.9rem;
  padding: 1rem 1.2rem;
}

.theory-emphasis code {
  color: var(--accent-alt);
}

@media (max-width: 720px) {
  .hero__title {
    letter-spacing: 0.08em;
  }

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