* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f4f4;
    color: #222;
}

main {
    max-width: 960px;
    margin: 2rem auto;
    padding: 1.5rem;
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
}

h1 {
    margin: 0 0 0.5rem;
    font-size: 1.75rem;
}

.intro {
    margin: 0 0 1.5rem;
    color: #555;
}

.panes {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.pane {
    flex: 1;
    min-width: 260px;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-weight: 600;
}

textarea {
    width: 100%;
    min-height: 300px;
    padding: 0.75rem;
    font-family: "Courier New", Courier, monospace;
    font-size: 0.95rem;
    line-height: 1.5;
    border-radius: 6px;
    border: 1px solid #bbb;
    background: #fff;
    color: #222;
    resize: vertical;
}

textarea:focus {
    outline: 2px solid #3b82f6;
    border-color: #3b82f6;
}

textarea[readonly] {
    background: #f7f7f7;
}

.actions {
    margin-top: 1.5rem;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.75rem;
}

button {
    background: #2563eb;
    color: #fff;
    font-weight: 600;
    border: 1px solid #1d4ed8;
    border-radius: 4px;
    padding: 0.6rem 1.2rem;
    cursor: pointer;
}

button:hover {
    background: #1d4ed8;
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.button-like {
    display: inline-block;
    background: #2563eb;
    color: #fff;
    font-weight: 600;
    border: 1px solid #1d4ed8;
    border-radius: 4px;
    padding: 0.6rem 1.2rem;
    cursor: pointer;
    text-decoration: none;
}

.button-like:hover {
    background: #1d4ed8;
}

#file-input {
    display: none;
}

#status {
    min-height: 1.4rem;
    flex: 1;
    color: #444;
}

#status.error {
    color: #c0392b;
}

@media (max-width: 720px) {
    main {
        margin: 1rem;
        padding: 1rem;
    }

    textarea {
        min-height: 220px;
    }
}