/* ---------- shared button system ---------- */

.btn {
  --btn-fg: #fff;
  --btn-bg: var(--charcoal);
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--heading);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border-radius: var(--radius);
  text-decoration: none;
  cursor: pointer;
  border: none;
  overflow: hidden;
  isolation: isolate;
  transition: transform var(--dur-fast) var(--ease-ui), box-shadow var(--dur-fast) var(--ease-ui), border-color var(--dur-fast) var(--ease-ui), color var(--dur-fast) var(--ease-ui);
}

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

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

.btn:active {
  transform: scale(0.97);
  transition-duration: 90ms;
  transition-timing-function: var(--ease-press);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* fill-sweep primary: a pseudo-element sweeps in from the left on hover */
.btn--primary {
  background: var(--btn-bg);
  color: var(--btn-fg);
  padding: 14px 24px;
  font-size: 13px;
}

.btn--primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: color-mix(in srgb, var(--btn-bg) 70%, #000 30%);
  transform: translateX(-100%);
  transition: transform var(--dur-fast) var(--ease-ui);
  z-index: -1;
}

.btn--primary:hover::before {
  transform: translateX(0);
}

.topbar__cta.btn--primary {
  padding: 10px 20px;
}

/* outline: border draws / fills */
.btn--outline {
  background: transparent;
  border: 1px solid #fff;
  color: #fff;
  padding: 13px 27px;
}

.btn--outline::before {
  content: '';
  position: absolute;
  inset: 0;
  background: #fff;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-fast) var(--ease-ui);
  z-index: -1;
}

.btn--outline:hover {
  color: var(--charcoal);
}

.btn--outline:hover::before {
  transform: scaleX(1);
}

/* secondary: light card button (used on light/on-dark-card contexts, e.g. reset) */
.btn--secondary {
  background: var(--role-bg);
  border: 1px solid var(--role-line);
  border-radius: var(--radius);
  padding: 8px 16px;
  font-family: var(--heading);
  font-weight: 600;
  font-size: 14px;
  color: var(--role-text);
}

.btn--secondary:hover {
  border-color: var(--role-accent);
  color: var(--charcoal);
}

/* on the brush-reveal charcoal section, the reset button needs a dark-safe treatment */
.brush-reveal .btn--secondary {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.25);
  color: var(--bg-soft);
}

.brush-reveal .btn--secondary:hover {
  border-color: var(--sage);
  background: rgba(255, 255, 255, 0.14);
}

/* text link: underline draw */
.btn--text {
  background: none;
  border: none;
  padding: 6px 0;
  font-family: var(--heading);
  font-weight: 600;
  font-size: 13.5px;
  color: var(--role-text-muted);
  position: relative;
}

.btn--text::after {
  content: '';
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 2px;
  height: 1px;
  background: currentColor;
  transition: right var(--dur-fast) var(--ease-ui);
}

.btn--text:hover {
  color: var(--charcoal);
}

.btn--text:hover::after {
  right: 0;
}

/* generic focus ring reinforcement for all interactive controls */
.btn:focus-visible,
.compare-frame__range:focus-visible,
.process__tab:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 3px;
}

/* magnetic wrapper -- buttons.js applies transform directly, this just
   ensures the transition is smooth when it springs back */
[data-magnetic] {
  transition: transform 0.35s var(--ease-ui);
}