/* ═══════════════════════════════════════════════════════════
   BASE — layout primitives, typography, buttons, sections
   Extends the portfolio's language into the components an LMS
   needs but a portfolio never had.
   ═══════════════════════════════════════════════════════════ */

/* ═══════════ PAGE SHELL ═══════════ */
.site-main {
  /* header is fixed; reserve its height so nothing sits under it.
     Explicit reservation = no CLS. */
  padding-top: var(--nav-h);
  min-height: 60vh;
}
.shell {
  width: var(--shell);
  margin-inline: auto;
}
.section {
  padding-block: clamp(3rem, 7vw, 7rem);
}
.section--tight {
  padding-block: clamp(2rem, 4vw, 3.5rem);
}

/* ═══════════ TYPE ═══════════ */
.section-header {
  max-width: 1400px;
  margin: 0 auto clamp(2.5rem, 5vw, 4rem);
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  border-bottom: 1px solid var(--border);
  padding-bottom: clamp(1.5rem, 3vw, 2rem);
  flex-wrap: wrap;
  gap: 1rem;
}
.section-label {
  font-size: 0.65rem;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 0.75rem;
}
.section-title {
  font-family: "Bebas Neue", sans-serif;
  font-size: clamp(2.5rem, 6vw, 6rem);
  line-height: 0.9;
  color: var(--white);
}
.section-count {
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  color: var(--mid);
}
.page-title {
  font-family: "Bebas Neue", sans-serif;
  font-size: clamp(2rem, 5vw, 4rem);
  line-height: 0.95;
  letter-spacing: 0.02em;
}
.eyebrow {
  font-size: 0.65rem;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--cyan);
}
.lede {
  font-size: clamp(0.85rem, 1.4vw, 1rem);
  line-height: 1.75;
  color: rgba(238, 240, 245, 0.72);
  max-width: 62ch;
}
.muted {
  color: var(--mid);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
}

/* Long-form body copy (lesson text, course description) */
.prose {
  font-size: 0.9rem;
  line-height: 1.85;
  color: rgba(238, 240, 245, 0.8);
  max-width: 72ch;
}
.prose > * + * {
  margin-top: 1.25em;
}
.prose h2,
.prose h3,
.prose h4 {
  font-family: "Syne", sans-serif;
  font-weight: 800;
  color: var(--white);
  line-height: 1.25;
  letter-spacing: 0.01em;
}
.prose h2 {
  font-size: 1.4rem;
  margin-top: 2em;
}
.prose h3 {
  font-size: 1.1rem;
  margin-top: 1.75em;
}
.prose a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.prose ul,
.prose ol {
  padding-left: 1.4em;
}
.prose li + li {
  margin-top: 0.5em;
}
.prose li::marker {
  color: var(--cyan);
}
.prose strong {
  color: var(--white);
}
.prose blockquote {
  border-left: 2px solid var(--cyan);
  padding-left: 1.25rem;
  color: var(--white);
}
.prose code {
  background: var(--gray2);
  padding: 0.15em 0.4em;
  font-size: 0.9em;
}
.prose img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ═══════════ BUTTONS ═══════════
   Derived from the portfolio's .hero-btn. Same metrics, same motion. */
.btn {
  font-family: "Space Mono", monospace;
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 0.75rem 1.8rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6em;
  background: transparent;
  border: 1px solid transparent;
  color: var(--white);
  transition: background 0.25s, color 0.25s, border-color 0.25s, opacity 0.25s;
  /* tap target — never below 44px on touch */
  min-height: 44px;
}
.btn--primary {
  background: var(--cyan);
  color: var(--black);
  border-color: var(--cyan);
}
.btn--primary:hover {
  background: transparent;
  color: var(--cyan);
}
.btn--secondary {
  background: transparent;
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.2);
}
.btn--secondary:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}
.btn--ghost {
  padding-inline: 0;
  color: var(--mid);
}
.btn--ghost:hover {
  color: var(--cyan);
}
.btn--danger {
  border-color: rgba(255, 92, 106, 0.4);
  color: var(--danger);
}
.btn--danger:hover {
  background: var(--danger);
  color: var(--black);
}
.btn--block {
  width: 100%;
}
.btn--lg {
  font-size: 0.72rem;
  padding: 1rem 2.4rem;
}
.btn[disabled],
.btn.is-loading {
  opacity: 0.45;
  pointer-events: none;
}
.btn.is-loading::after {
  content: "";
  width: 0.9em;
  height: 0.9em;
  border: 1px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: btnspin 0.7s linear infinite;
}
@keyframes btnspin {
  to {
    transform: rotate(360deg);
  }
}

/* Keyboard focus — visible, on-brand, never removed */
:where(a, button, input, select, textarea, [tabindex]):focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

/* ═══════════ NOTICES ═══════════ */
.notice {
  border: 1px solid var(--border);
  border-left-width: 2px;
  background: var(--gray);
  padding: 0.9rem 1.1rem;
  font-size: 0.75rem;
  line-height: 1.7;
  letter-spacing: 0.04em;
}
.notice + .notice {
  margin-top: 0.75rem;
}
.notice--error {
  border-left-color: var(--danger);
  color: #ffd9dd;
}
.notice--success {
  border-left-color: var(--success);
  color: #d6fff0;
}
.notice--info {
  border-left-color: var(--cyan);
  color: var(--white);
}
.notice a {
  color: var(--cyan);
}
.notice ul {
  padding-left: 1.2em;
}

/* ═══════════ REVEAL ═══════════ */
.reveal {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity 0.8s, transform 0.8s;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}
/* If JS never runs, content must still be visible. */
.no-js .reveal {
  opacity: 1;
  transform: none;
}

/* ═══════════ UTILITIES ═══════════ */
.stack > * + * {
  margin-top: var(--stack-gap, 1rem);
}
.cluster {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
}
.between {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}
.tag {
  font-size: 0.6rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
  border: 1px solid var(--cyandim);
  background: rgba(0, 222, 255, 0.05);
  padding: 0.3rem 0.65rem;
}
.divider {
  height: 1px;
  background: var(--border);
  border: 0;
}
.screen-reader-text,
.sr-only {
  position: absolute !important;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
  clip-path: inset(50%);
  white-space: nowrap;
}
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 10000;
  background: var(--cyan);
  color: var(--black);
  padding: 0.75rem 1.25rem;
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.skip-link:focus {
  left: 0;
}

/* ═══════════ EMPTY STATES ═══════════ */
.empty-state {
  border: 1px dashed var(--border);
  padding: clamp(2rem, 5vw, 4rem);
  text-align: center;
}
.empty-state .es-title {
  font-family: "Bebas Neue", sans-serif;
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  letter-spacing: 0.06em;
  margin-bottom: 0.75rem;
}
.empty-state .es-sub {
  color: var(--mid);
  font-size: 0.8rem;
  line-height: 1.7;
  margin-bottom: 1.5rem;
}

/* ═══════════ MEDIA ═══════════ */
.ratio {
  position: relative;
  width: 100%;
  background: var(--gray2);
  overflow: hidden;
}
/* aspect-ratio reserved up front — this is the CLS guard */
.ratio--16x9 {
  aspect-ratio: 16 / 9;
}
.ratio--9x16 {
  aspect-ratio: 9 / 16;
}
.ratio--4x3 {
  aspect-ratio: 4 / 3;
}
.ratio > img,
.ratio > video,
.ratio > iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  border: 0;
  display: block;
}