/* ============================================================
   Buttons
   ============================================================ */

.btn {
  position: relative;
  border: 1px solid transparent;
  padding: 0.9rem 1.5rem;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: transform 0.4s var(--ease-out), background 0.3s linear,
              color 0.3s linear, border-color 0.3s linear, box-shadow 0.3s linear;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  overflow: hidden;
  isolation: isolate;
  background: transparent;
  color: var(--ink);
}

.btn::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--signal);
  border-radius: inherit;
  transform: translateY(101%);
  transition: transform 0.55s var(--ease-out);
  z-index: -1;
}

.btn:hover::before {
  transform: translateY(0);
}

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

.btn.primary::before {
  background: var(--signal);
}

.btn.primary:hover {
  color: var(--text-on-signal);
  border-color: var(--signal);
}

.btn.outline {
  border-color: var(--rule-strong);
  color: var(--ink);
}

.btn.outline:hover {
  color: var(--text-on-signal);
  border-color: var(--signal);
}

.btn.ghost {
  border-color: var(--rule);
}

.btn .arrow {
  display: inline-block;
  transition: transform 0.4s var(--ease-out);
}

.btn:hover .arrow {
  transform: translateX(4px) rotate(-45deg);
}

/* Theme toggle */
.theme-toggle {
  width: 44px;
  height: 44px;
  padding: 0;
  border-radius: 50%;
  border: 1px solid var(--rule-strong);
  background: transparent;
  cursor: pointer;
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--ink);
  transition: border-color 0.3s linear, color 0.3s linear, transform 0.4s var(--ease-spring);
}

.theme-toggle:hover {
  border-color: var(--signal);
  color: var(--signal);
  transform: rotate(180deg);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.theme-toggle__sun { display: block; }
.theme-toggle__moon { display: none; }

body[data-theme="dark"] .theme-toggle__sun { display: none; }
body[data-theme="dark"] .theme-toggle__moon { display: block; }

/* Nav toggle (mobile) */
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--rule-strong);
  background: transparent;
  border-radius: 50%;
  cursor: pointer;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
  transition: border-color 0.2s linear;
}

.nav-toggle__line {
  display: block;
  width: 18px;
  height: 1.5px;
  background: currentColor;
  transition: transform 0.3s var(--ease-out), opacity 0.2s linear;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__line:nth-child(3) {
  transform: translateY(-5.5px) rotate(-45deg);
}

/* ============================================================
   Cmd-K hint button (in nav)
   ============================================================ */

.cmd-k-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 0.65rem 0.45rem 0.85rem;
  border: 1px solid var(--rule-strong);
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  cursor: pointer;
  transition: color 0.2s linear, border-color 0.2s linear, background 0.2s linear;
}

.cmd-k-btn:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.cmd-k-btn kbd {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 0.1rem 0.4rem;
  border: 1px solid var(--rule);
  border-radius: 4px;
  background: var(--bg);
  color: var(--ink);
  line-height: 1;
}

@media (max-width: 880px) {
  .cmd-k-btn { display: none; }
}