/* ==========================================================================
   FIT BY SCIENCE - BUTTONS
   Default interaction is inversion/border/arrow movement.
   Science Blue is an occasional accent, not the default hover.
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: var(--text-label);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  white-space: nowrap;
  transition: background-color var(--duration-fast) var(--ease-standard),
              color var(--duration-fast) var(--ease-standard),
              border-color var(--duration-fast) var(--ease-standard);
}

.btn__arrow {
  display: inline-block;
  transition: transform var(--duration-fast) var(--ease-standard);
}

.btn:hover .btn__arrow {
  transform: translateX(4px);
}

/* Primary - Bone fill on dark surfaces. Default hover: quiet inversion. */
.btn--primary {
  background: var(--bone);
  color: var(--obsidian);
  border-color: var(--bone);
}

.btn--primary:hover {
  background: transparent;
  color: var(--bone);
  border-color: var(--bone);
}

/* Secondary - ghost, for lower-emphasis actions */
.btn--secondary {
  background: transparent;
  color: var(--bone);
  border-color: var(--stone);
}

.btn--secondary:hover {
  border-color: var(--bone);
  background: rgba(244, 242, 237, 0.06);
}

/* Accent variant - reserved for isolated moments where Science Blue earns its place */
.btn--accent:hover {
  background: var(--science-blue);
  color: var(--bone);
  border-color: var(--science-blue);
}