body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
    background-color: #f5f5f7;
    color: #1d1d1f;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    background-color: #ffffff;
    padding: 40px;
    border-radius: 18px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    text-align: center;
}

h1 {
    font-size: 28px;
    margin-bottom: 10px;
}

p {
    font-size: 16px;
    color: #6e6e73;
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
}

textarea, input[type="password"] {
    width: 100%;
    padding: 12px;
    border: 1px solid #d2d2d7;
    border-radius: 8px;
    font-size: 16px;
    box-sizing: border-box;
    resize: vertical;
}

textarea:focus, input[type="password"]:focus {
    outline: none;
    border-color: #007aff;
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.25);
}

.button-group {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

button {
    flex-grow: 1;
    background-color: #007aff;
    color: white;
    border: none;
    padding: 14px 0;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    transition: background-color 0.2s ease-in-out;
}

button:hover {
    background-color: #005ecb;
}

#decrypt-btn {
    background-color: #34c759;
}

#decrypt-btn:hover {
    background-color: #2ca349;
}

#result-output {
    background-color: #f5f5f7;
    cursor: not-allowed;
}