/* Utility classes — direct ports of the Lesson Lab @layer utilities (Tailwind expanded to plain CSS).
   These are the brand's canonical button/link/field/card recipes. */

/* Layout shells */
.section-shell {
  margin-inline: auto;
  max-width: 1280px;
  padding-inline: 24px;
}

.lp-shell {
  margin-inline: auto;
  max-width: var(--shell-max);
  padding-inline: 24px;
}

@media (min-width: 1024px) {
  .section-shell,
  .lp-shell {
    padding-inline: 40px;
  }
}

/* Hero background grid — 44px cells, centered at top */
.lp-hero-grid {
  background-image: linear-gradient(var(--lp-hairline) 1px, transparent 1px),
    linear-gradient(90deg, var(--lp-hairline) 1px, transparent 1px);
  background-size: var(--hero-grid-cell) var(--hero-grid-cell);
  background-position: center top;
}

/* Borders + shadows */
.surface-border {
  border: 1px solid var(--border);
}

.surface-shadow {
  box-shadow: var(--shadow-surface);
}

/* Buttons */
.btn-primary,
.btn-accent,
.btn-secondary,
.btn-ghost-dark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  white-space: nowrap;
  border-radius: var(--radius-btn);
  padding: 12px 20px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 200ms;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: var(--text-inverse);
  box-shadow: var(--shadow-card);
}

.btn-primary:hover {
  transform: translateY(-2px);
  background: var(--primary-hover);
  box-shadow: var(--shadow-cloud);
}

.btn-primary:active {
  background: var(--primary-pressed);
}

.btn-accent {
  background: var(--accent);
  color: var(--lp-ink);
  font-weight: 700;
  box-shadow: var(--shadow-card);
}

.btn-accent:hover {
  transform: translateY(-2px);
  background: rgb(var(--accent-rgb) / 0.9);
  box-shadow: var(--shadow-cloud);
}

.btn-accent:active {
  background: rgb(var(--accent-rgb) / 0.8);
}

.btn-secondary {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  box-shadow: 0 1px 2px 0 rgb(0 0 0 / 0.05);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  border-color: var(--text);
}

.btn-secondary:active {
  background: var(--surface-2);
}

.btn-ghost-dark {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.22);
  color: var(--lp-dark-text);
}

.btn-ghost-dark:hover {
  border-color: rgba(255, 255, 255, 0.4);
}

.btn-primary:disabled,
.btn-accent:disabled,
.btn-secondary:disabled {
  cursor: not-allowed;
  opacity: 0.6;
  transform: none;
}

/* Links */
.theme-link {
  font-size: 14px;
  font-weight: 600;
  color: var(--link);
  transition: color 150ms;
}

.theme-link:hover,
.theme-link:focus-visible {
  color: var(--link-hover);
  text-decoration: underline;
}

/* Form fields */
.field-control {
  border-radius: var(--radius-btn);
  border: 1px solid var(--border);
  background: var(--surface-2);
  padding: 12px 16px;
  font-size: 14px;
  color: var(--text-muted);
  transition: border-color 150ms;
}

.field-control::placeholder {
  color: var(--text-subtle);
}

.field-control:hover {
  border-color: var(--primary-soft);
}

.field-control:focus {
  border-color: var(--focus-ring);
}

/* Cards */
.paper-card {
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow-surface);
}

/* Emphasis span used inside app headings */
.serif-em {
  color: var(--primary);
  font-weight: 700;
  letter-spacing: -0.01em;
}

/* Mono labels + eyebrows */
.mono-label {
  font-family: var(--font-mono);
  font-size: var(--text-mono-label);
  letter-spacing: var(--tracking-mono-label);
  text-transform: uppercase;
}

.mono-eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-eyebrow);
  letter-spacing: var(--tracking-eyebrow);
  text-transform: uppercase;
  color: var(--primary);
}

/* Spinner */
@keyframes ds-spin {
  to {
    transform: rotate(360deg);
  }
}

.ds-spin {
  animation: ds-spin 1s linear infinite;
}