.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 40px;
  padding: 0 16px;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.005em;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background-color 0.15s var(--ease),
              border-color 0.15s var(--ease),
              color 0.15s var(--ease),
              box-shadow 0.15s var(--ease),
              transform 0.1s var(--ease);
  white-space: nowrap;
  text-decoration: none;
}
.btn:disabled { opacity: 0.55; cursor: not-allowed; }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--unique) 30%, transparent);
}

.btn-sm { height: 34px; padding: 0 12px; font-size: 14px; }
.btn-lg { height: 48px; padding: 0 20px; font-size: 16px; }

.btn-primary {
  background: var(--unique);
  color: #fff;
  box-shadow: 0 1px 2px rgba(11, 37, 69, 0.12),
              inset 0 1px 0 rgba(255, 255, 255, 0.18);
}
.btn-primary:hover:not(:disabled) {
  background: color-mix(in srgb, var(--unique) 88%, black);
}

.btn-brand {
  background: var(--brand-deep);
  color: #fff;
  box-shadow: 0 1px 2px rgba(11, 37, 69, 0.18),
              inset 0 1px 0 rgba(255, 255, 255, 0.08);
}
.btn-brand:hover:not(:disabled) {
  background: color-mix(in srgb, var(--brand-deep) 85%, white);
}

.btn-secondary {
  background: var(--text);
  color: var(--background);
}
.btn-secondary:hover:not(:disabled) {
  background: color-mix(in srgb, var(--text) 88%, white);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}
.btn-outline:hover:not(:disabled) {
  background: color-mix(in srgb, var(--unique) 8%, transparent);
  border-color: color-mix(in srgb, var(--unique) 25%, var(--border));
  color: var(--unique);
}

.btn-ghost {
  background: transparent;
  color: var(--text);
}
.btn-ghost:hover:not(:disabled) {
  background: color-mix(in srgb, var(--unique) 10%, transparent);
  color: var(--unique);
}

.btn-icon {
  width: 40px;
  padding: 0;
  border-radius: var(--radius-pill);
}
.btn-icon.btn-sm { width: 34px; }
.btn-icon.btn-lg { width: 48px; }