body { 
        background-color: #f5f5f7; 
        min-height: 100vh; 
        display: flex; 
        flex-direction: column; 
    }
    main { 
        flex: 1; 
        display: flex; 
        flex-direction: column;
        align-items: center; 
        justify-content: flex-start; 
        width: 100%; 
        padding: 40px 20px; 
        position: relative;
        z-index: 1;
        gap: 40px;
    }
    .content-box { 
        width: 100%;
        max-width: 98%; 
        padding: 40px; 
        text-align: center; 
        background: rgba(255,255,255,0.85);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-radius: 24px;
        box-shadow: 0 20px 40px rgba(0,0,0,0.05);
        border: 1px solid rgba(255,255,255,0.5);
        animation: fadeUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    }
    h1 {
        font-size: clamp(2rem, 5vw, 3rem);
        color: #1d1d1f;
        margin-bottom: 15px;
        letter-spacing: -1px;
    }
    .form-group { margin-bottom: 20px; margin-top: 30px; }
    #urlInput {
        width: 50%;
        display: block;
        margin: 0 auto;
        padding: 12px 15px;
        border-radius: 12px;
        border: 1px solid #d2d2d7;
        font-size: 0.95rem;
        outline: none;
        transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
        background: #fff;
    }
    #urlInput:focus {
        border-color: #007AFF;
        box-shadow: 0 0 0 4px rgba(0,122,255,0.15);
    }
    #encodeBtn {
        padding: 12px 24px;
        border-radius: 50px;
        border: none;
        background: #007AFF;
        color: white;
        font-size: 1rem;
        font-weight: 600;
        cursor: pointer;
        transition: all 0.3s ease;
        box-shadow: 0 4px 12px rgba(0,122,255,0.3);
        width: 50%;
    }
    #encodeBtn:hover { 
        background: #0056b3; 
        transform: translateY(-2px);
        box-shadow: 0 6px 16px rgba(0,122,255,0.4);
    }
    #result-section { 
        margin-top: 30px; 
        padding-top: 30px; 
        border-top: 1px solid rgba(0,0,0,0.05); 
        animation: fadeIn 0.5s ease;
    }
    @keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
    .result-box { 
        display: flex; 
        gap: 10px; 
        width: 80%;
        margin: 0 auto;
        background: #f2f2f7;
        padding: 6px;
        border-radius: 14px;
        border: 1px solid rgba(0,0,0,0.05);
    }
    #resultUrl {
        flex-grow: 1;
        padding: 8px 12px;
        border-radius: 10px;
        border: none;
        background: transparent;
        font-family: 'SF Mono', 'Menlo', 'Monaco', 'Courier New', monospace;
        font-size: 0.9rem;
        color: #333;
        outline: none;
    }
    #copyBtn {
        padding: 10px 20px;
        border-radius: 10px;
        border: none;
        background: #fff;
        color: #007AFF;
        font-weight: 600;
        cursor: pointer;
        box-shadow: 0 2px 8px rgba(0,0,0,0.05);
        transition: 0.2s;
    }
    #copyBtn:hover { background: #fff; color: #0056b3; transform: scale(1.02); }
    #copyBtn:active { transform: scale(0.98); }

    /* New Password Styles */
    .form-group.checkbox-group {
        display: flex;
        align-items: center;
        gap: 10px;
        justify-content: center;
        margin-top: 25px;
        margin-bottom: 15px;
    }
    #passwordToggle { width: 18px; height: 18px; cursor: pointer; }
    .form-group.checkbox-group label { font-weight: 600; cursor: pointer; color: #333; }

    #password-input-container, #password-prompt-section .form-group {
        position: relative;
        margin-top: 0;
        margin-bottom: 25px;
    }
    #passwordInput, #redirectPasswordInput {
        width: 100%;
        padding: 12px 40px 12px 15px;
        border-radius: 12px;
        border: 1px solid #d2d2d7;
        font-size: 0.95rem;
        outline: none;
        transition: all 0.3s;
        background: #fff;
    }
    #passwordInput:focus, #redirectPasswordInput:focus {
        border-color: #007AFF;
        box-shadow: 0 0 0 4px rgba(0,122,255,0.15);
    }
    #togglePassVisibility {
        position: absolute;
        right: 15px; top: 50%;
        transform: translateY(-50%);
        background: none; border: none; cursor: pointer;
        font-size: 1.2rem; color: #888;
    }
    #decryptBtn { /* Re-use encodeBtn styles */
        padding: 12px 24px; border-radius: 50px; border: none; background: #007AFF; color: white;
        font-size: 1rem; font-weight: 600; cursor: pointer; transition: all 0.3s ease;
        box-shadow: 0 4px 12px rgba(0,122,255,0.3); width: 100%;
    }
    #decryptBtn:hover { background: #0056b3; transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,122,255,0.4); }

    #redirect-section { padding: 40px 20px; }
    #redirect-section h2 { font-size: 1.8rem; }
    #redirect-section p { color: #555; }
    #redirectLink { word-break: break-all; }
    
    .loader {
        border: 3px solid #f3f3f3;
        border-radius: 50%;
        border-top: 3px solid #007AFF;
        width: 40px;
        height: 40px;
        animation: spin 1s linear infinite;
        margin: 0 auto 20px;
    }
    .secondary-btn {
        padding: 10px 20px;
        border-radius: 10px;
        border: 1px solid #d2d2d7;
        background: #fff;
        color: #1d1d1f;
        font-weight: 600;
        cursor: pointer;
        transition: 0.2s;
    }
    .secondary-btn:hover { background: #f5f5f7; transform: translateY(-1px); }
    
    .info-section {
        max-width: 98%;
        width: 100%;
        text-align: left;
        background: rgba(255,255,255,0.6);
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
        padding: 40px;
        border-radius: 24px;
        box-shadow: 0 4px 20px rgba(0,0,0,0.02);
    }
    .info-section h2 { margin-bottom: 20px; font-size: clamp(1.5rem, 2.5vw, 2rem); color: #1d1d1f; font-weight: 800; }
    .info-section h3 { margin: 25px 0 10px; font-size: 1.3rem; color: #1d1d1f; font-weight: 700; }
    .info-section p, .info-section li { color: #444; line-height: 1.7; margin-bottom: 15px; font-size: clamp(0.95rem, 1.05vw, 1.05rem); }
    .info-section ul, .info-section ol { padding-left: 20px; margin-bottom: 20px; }
    .info-section li { margin-bottom: 8px; }
    .example-box {
        background: #f5f5f7;
        padding: 15px;
        border-radius: 12px;
        font-family: monospace;
        color: #333;
        word-break: break-all;
        border: 1px solid rgba(0,0,0,0.05);
    }
    .features-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 20px;
        margin: 40px 0;
        text-align: left;
    }
    .feature-card {
        background: rgba(255,255,255,0.7);
        padding: 20px;
        border-radius: 16px;
        border: 1px solid rgba(0,0,0,0.05);
    }
    .feature-icon { font-size: 2rem; margin-bottom: 10px; display: block; }
    .feature-title { font-weight: 700; margin-bottom: 8px; color: #1d1d1f; font-size: 1.1rem; }
    .feature-desc { font-size: 0.95rem; color: #555; line-height: 1.5; }
    details { margin-bottom: 15px; border-bottom: 1px solid rgba(0,0,0,0.05); padding-bottom: 15px; text-align: left; }
    summary { font-weight: 700; cursor: pointer; color: #1d1d1f; list-style: none; display: flex; align-items: center; justify-content: space-between; font-size: 1.05rem; }
    summary::-webkit-details-marker { display: none; }
    summary::after { content: '+'; font-size: 1.2rem; font-weight: 400; color: #007AFF; }
    details[open] summary::after { content: '−'; }
    details p { margin-top: 10px; color: #555; line-height: 1.6; font-size: 1rem; }
    @keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }
    
    @media(max-width: 500px) {
        .content-box { padding: 30px 20px; }
        h1 { font-size: 1.8rem; }
    }