.app{max-width:500px;margin:50px auto;text-align:center}.btn{padding:12px 24px;background:#42b983;color:#fff;border:none;border-radius:8px;font-size:16px;cursor:pointer}.preview,.result-img{max-width:220px;margin:20px auto;display:block;border:1px solid #eee}.colors button{margin:0 10px;padding:8px 16px;border:none;border-radius:6px;cursor:pointer}.result button{padding:10px 20px;background:#409eff;color:#fff;border:none;border-radius:8px;cursor:pointer}