.btn{display:inline-flex;align-items:center;justify-content:center;gap:var(--space-2);padding:var(--space-3) var(--space-6);font-family:var(--font-sans);font-size:var(--text-base);font-weight:var(--weight-semibold);line-height:1;text-align:center;text-decoration:none;border:2px solid transparent;border-radius:var(--radius-md);cursor:pointer;transition:all var(--transition-base);user-select:none;white-space:nowrap;min-height:44px;min-width:fit-content}.btn:focus-visible{outline:2px solid var(--color-primary);outline-offset:2px}.btn:disabled{opacity:.5;cursor:not-allowed;pointer-events:none}.btn-primary{background:var(--color-primary);color:#fff;border-color:var(--color-primary)}.btn-primary:hover{background:var(--color-primary-dark);border-color:var(--color-primary-dark);transform:translateY(-2px);box-shadow:0 8px 16px rgba(37,99,235,.3)}.btn-primary:active{transform:translateY(0);box-shadow:0 4px 8px rgba(37,99,235,.3)}.btn-secondary{background:0 0;color:var(--color-primary-light);border-color:var(--color-primary)}.btn-secondary:hover{background:var(--color-primary);color:#fff;border-color:var(--color-primary);transform:translateY(-2px);box-shadow:0 8px 16px rgba(37,99,235,.2)}.btn-secondary:active{transform:translateY(0)}.btn-ghost{background:0 0;color:var(--color-text-secondary);border-color:transparent}.btn-ghost:hover{color:var(--color-primary-light);background:rgba(37,99,235,.1)}.btn-danger{background:var(--color-error);color:#fff;border-color:var(--color-error)}.btn-danger:hover{background:#dc2626;border-color:#dc2626;transform:translateY(-2px);box-shadow:0 8px 16px rgba(239,68,68,.3)}.btn-success{background:var(--color-success);color:#fff;border-color:var(--color-success)}.btn-success:hover{background:#059669;border-color:#059669;transform:translateY(-2px);box-shadow:0 8px 16px rgba(16,185,129,.3)}.btn-sm{padding:var(--space-2) var(--space-4);font-size:var(--text-sm);min-height:36px}.btn-lg{padding:var(--space-4) var(--space-8);font-size:var(--text-lg);min-height:52px}.btn-xl{padding:var(--space-5) var(--space-10);font-size:var(--text-xl);min-height:60px}.btn-block{width:100%;display:flex}.btn-icon{padding:var(--space-3);min-width:44px;aspect-ratio:1}.btn-icon svg{width:20px;height:20px}.btn.is-loading{position:relative;color:transparent;pointer-events:none}.btn.is-loading::after{content:'';position:absolute;width:16px;height:16px;top:50%;left:50%;margin-left:-8px;margin-top:-8px;border:2px solid currentColor;border-radius:50%;border-right-color:transparent;animation:spin .6s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.btn-group{display:inline-flex;gap:var(--space-2);flex-wrap:wrap}.btn-group .btn{flex:0 1 auto}.btn-group-vertical{display:flex;flex-direction:column;gap:var(--space-2)}.btn-group-vertical .btn{width:100%}.btn-fab{position:fixed;bottom:var(--space-6);right:var(--space-6);width:56px;height:56px;padding:0;border-radius:var(--radius-full);box-shadow:var(--shadow-lg);z-index:var(--z-fixed)}.btn-fab:hover{box-shadow:var(--shadow-xl);transform:scale(1.05)}.btn-fab svg{width:24px;height:24px}@media (min-width:768px){.btn-block{width:auto;display:inline-flex}.btn-group{flex-wrap:nowrap}}@media (min-width:1024px){.btn{padding:var(--space-4) var(--space-8)}.btn-lg{padding:var(--space-5) var(--space-10)}}