body{margin:0;padding:0;background:#46515c;font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif}.app{display:flex;justify-content:center;align-items:flex-start;padding:3rem 1rem;min-height:100vh;box-sizing:border-box}.card{background:#fff;border-radius:16px;padding:2rem;max-width:100%;width:100%;box-shadow:0 10px 25px #00000014}.title{font-size:2rem;font-weight:700;color:#1e3a8a;margin-bottom:1rem;text-align:center}.intro{font-size:1rem;color:#374151;margin-bottom:1.5rem;line-height:1.6}.section-header{font-size:1.2rem;margin-top:1.5rem;margin-bottom:.5rem;color:#111827}.textarea{width:100%;padding:1rem;font-size:1rem;border:1px solid #cbd5e1;border-radius:8px;resize:vertical;box-sizing:border-box}.input{width:100%;max-width:120px;padding:.6rem;font-size:1rem;border:1px solid #cbd5e1;border-radius:8px;box-sizing:border-box}.button-group{margin-top:1.5rem}.button{padding:.6rem 1.2rem;margin-right:1rem;font-size:1rem;font-weight:700;border:none;border-radius:8px;cursor:pointer;transition:background .3s ease}.encrypt{background-color:#2563eb;color:#fff}.encrypt:hover{background-color:#1d4ed8}.decrypt{background-color:#16a34a;color:#fff}.decrypt:hover{background-color:#15803d}.output-box{margin-top:1rem;padding:1rem;min-height:3rem;background-color:#fef2f2;border:1px solid #fecaca;border-radius:8px;color:#991b1b;font-family:monospace;white-space:pre-wrap;word-break:break-word}.muted{color:#9ca3af;font-style:italic}