/* ===== Site-wide button (Sharplink-style), in Mendel brand colours =====
   Plaster label + Oxide Clay arrow square. On hover the label text rolls up, the label
   slides right, the arrow square exits up-right and a new one enters from the left.
   Markup is built by assets/js/buttons.js from any element with [data-sl]. */
.sl-btn {
  --sl-bg: #EFEBE1;        /* Soft Plaster */
  --sl-fg: #191814;        /* Charcoal Black */
  --sl-accent: #983201;    /* Oxide Clay */
  --sl-accent-fg: #EFEBE1;
  --sl-h: 40px;
  --sl-icon: 40px;
  --sl-gap: 2px;
  --sl-ease: cubic-bezier(.785, .135, .15, .86);

  position: relative;
  display: inline-flex; gap: var(--sl-gap);
  height: var(--sl-h);
  overflow: hidden;
  padding: 0; margin: 0; border: 0; border-radius: 0; background: none;
  font: 500 12px/1.4 "Geist", "Helvetica Neue", Arial, sans-serif;
  letter-spacing: .12em; text-transform: uppercase;
  text-decoration: none; white-space: nowrap;
  cursor: pointer; user-select: none;
  -webkit-tap-highlight-color: transparent;
}

/* label: two copies stacked, rolled up on hover */
.sl-btn__label {
  flex: 1 1 auto;
  display: flex; flex-direction: column;
  padding: 0 20px;
  background: var(--sl-bg); color: var(--sl-fg);
  overflow: hidden;
  transition: transform .5s var(--sl-ease);
}
/* inner spans must not pick up generic "span" rules from where the button sits (e.g. footer) */
.sl-btn .sl-btn__label, .sl-btn .sl-btn__icon, .sl-btn .sl-btn__icon > span {
  font: inherit; letter-spacing: inherit; text-transform: inherit; text-decoration: none;
}
.sl-btn .sl-btn__label > span {
  height: var(--sl-h); flex-shrink: 0;
  color: var(--sl-fg); font: inherit; letter-spacing: inherit;
  display: flex; align-items: center; justify-content: center;
  transition: transform .5s var(--sl-ease) .07s;
}

/* arrow square */
.sl-btn__icon {
  width: var(--sl-icon); height: var(--sl-h); flex-shrink: 0;
  display: flex; flex-direction: column; overflow: hidden;
  background: var(--sl-accent); color: var(--sl-accent-fg);
  transition: transform .5s var(--sl-ease);
}
.sl-btn__icon > span {
  height: var(--sl-h); flex-shrink: 0;
  display: grid; place-items: center;
  transition: transform .5s var(--sl-ease);
}
.sl-btn__icon svg { width: 18px; height: 18px; }
.sl-btn--sm .sl-btn__icon svg { width: 16px; height: 16px; }
/* arrow direction variants */
.sl-btn--ext .sl-btn__icon svg { transform: none; }              /* ↗ opens elsewhere */
.sl-btn--up .sl-btn__icon svg { transform: rotate(-45deg); }    /* ↑ back to top */
.sl-btn--back .sl-btn__icon svg { transform: rotate(-135deg); } /* ← back */

/* the incoming square waits off-frame, bottom-left */
.sl-btn__icon--in { position: absolute; top: 100%; left: 0; transform: translateX(-100%); }

/* ===== hover / keyboard focus ===== */
.sl-btn:hover .sl-btn__label > span,
.sl-btn:hover .sl-btn__icon > span,
.sl-btn:focus-visible .sl-btn__label > span,
.sl-btn:focus-visible .sl-btn__icon > span { transform: translateY(-100%); transition-delay: .12s; }
.sl-btn:hover .sl-btn__label,
.sl-btn:focus-visible .sl-btn__label { transform: translateX(calc(var(--sl-icon) + var(--sl-gap))); transition-delay: .12s; }
.sl-btn:hover .sl-btn__icon--out,
.sl-btn:focus-visible .sl-btn__icon--out { transform: translate(calc(var(--sl-icon) + var(--sl-gap)), -100%); }
.sl-btn:hover .sl-btn__icon--in,
.sl-btn:focus-visible .sl-btn__icon--in { transform: translateY(-100%); transition-delay: .12s; }

.sl-btn:focus-visible { outline: 1px solid var(--sl-accent); outline-offset: 3px; }
.sl-btn[disabled] { opacity: .5; cursor: progress; pointer-events: none; }

/* sizes */
.sl-btn--sm { --sl-h: 36px; --sl-icon: 36px; font-size: 11px; }
.sl-btn--lg { --sl-h: 52px; --sl-icon: 52px; font-size: 13px; }
.sl-btn--lg .sl-btn__label { padding: 0 28px; }
.sl-btn--block { display: flex; width: 100%; }

@media (hover: none) {
  /* touch: no hover choreography, the button just stays as it is */
  .sl-btn .sl-btn__label, .sl-btn .sl-btn__label > span, .sl-btn .sl-btn__icon, .sl-btn .sl-btn__icon > span { transform: none !important; }
}
@media (prefers-reduced-motion: reduce) {
  .sl-btn, .sl-btn * { transition: none !important; }
}