@import "https://unpkg.com/water.css@2/out/water.min.css";

body {
    display: flex;
    font-size: 1.5em;
    justify-content: center;
}

main {
    width: clamp(45ch, 50%, 75ch);
    display: flex;
    flex-direction: column;
}

textarea {
    transition: .2s;
    resize: none;
    overflow: hidden;
    background: white;
    border: 1px solid black;
}

textarea:focus {
    border: 1px solid orange;
    outline: none;
}

section {
    display: flex;
    flex-direction: column;
}

button {
    margin: 0 0 0 auto;
    background: orange;
    color: white;
    cursor: pointer;
    border: none;
    padding: 0.5em 1em;
    font-size: 1em;
}

button:hover {
    background: orange;
}

.posted-text {
    margin-top: 1em;
    border: 1px solid #ddd;
    padding: 0.5em;
}

.valid-btc {
    border: 5px solid orange;
}

.invalid-btc {
    border: 5px solid red;
}