body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: flex-start; /* Align to top to better see content */
    min-height: 100vh;
    margin: 0;
    padding: 2rem 0;
    background-color: #f0f2f5;
    color: #333;
}

.container {
    width: 90%;
    max-width: 700px;
    background-color: #ffffff;
    padding: 2rem 2.5rem;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    font-size: 2em;
    margin-bottom: 0.5em;
    color: #1a202c;
}

.subtitle {
    text-align: center;
    color: #718096;
    margin-bottom: 2.5em;
    font-style: italic;
}

.input-group {
    margin-bottom: 1.5em;
}

.input-group label {
    display: block;
    font-weight: bold;
    margin-bottom: 0.5em;
}

input[type="file"], input[type="password"] {
    width: 100%;
    padding: 0.8em;
    border: 1px solid #cbd5e0;
    border-radius: 4px;
    font-size: 1em;
    box-sizing: border-box; /* Important for padding */
}

button {
    width: 100%;
    font-size: 1.2em;
    font-weight: bold;
    color: #ffffff;
    background-color: #4299e1; /* A nice blue */
    border: none;
    padding: 0.8em 1em;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.1s ease;
    margin-top: 1em;
}

button:hover {
    background-color: #3182ce;
}

button:active {
    transform: scale(0.99);
}

button:disabled {
    background-color: #a0aec0;
    cursor: not-allowed;
}

#status-section {
    margin-top: 1.5em;
    text-align: center;
    min-height: 1.5em;
}

#status-message {
    font-weight: bold;
    font-size: 1.1em;
    padding: 0.5em;
    border-radius: 4px;
}

.status-error {
    color: #e53e3e;
    background-color: #fed7d7;
}

.status-success {
    color: #38a169;
    background-color: #c6f6d5;
}

.status-processing {
    color: #3182ce;
}

.hidden {
    display: none;
}

#result-section {
    margin-top: 2em;
}

#result-section h2 {
    margin-bottom: 0.5em;
}

#decrypted-text {
    width: 100%;
    box-sizing: border-box;
    padding: 1em;
    font-family: "Courier New", Courier, monospace;
    background-color: #edf2f7;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    resize: vertical;
}

#copyBtn {
    width: auto;
    background-color: #38a169;
    font-size: 1em;
    padding: 0.6em 1.2em;
    margin-top: 0.5em;
}

#copyBtn:hover {
    background-color: #2f855a;
}