styles.css

body {
    line-height: 1.2;
    font-family: monospace;
    font-size: 18px;
}

main {
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

body > h1 {
    text-align: center;
}

p, li  {
    margin: 0.5em 0;
}

fieldset ul {
    padding-left: 0;
}

fieldset li {
    list-style-type: none;
}

button, input, select {
    font-family: monospace;
    font-size: 18px;
}

.parties {
    display: flex;
    justify-content: space-between;
}

.party {
    width: calc(50% - 2em);
    margin-left: 2em;
}

.party:first-child {
    margin-left: 0;
}

.party h1 {
    border-bottom: 1px solid #000;
}

.party li {
    list-style: none;
    text-transform: capitalize;
    position: relative;
}

.party ul {
    padding-left: 0;
}

.dead {
    text-decoration: line-through;
}

.active {
    background: rgba(255, 255, 0, 0.5);
}

.heroes{
    background: rgba(153, 255, 0, 0.5);
}

.monsters{
    background: rgba(255, 51, 0, 0.5);
}
.active::before {
    content: "► ";
    display: block;
    position: absolute;
    left: -1em;
}

.info {
    padding: 1em;
    background: #efefef;
    box-sizing: border-box;
}

.info strong {
    text-transform: capitalize;
}

.battle-menu .choices {
    text-transform: capitalize;
    padding-left: 0;
}

.battle-menu .choices li {
    list-style-type: none;
}

.battle-menu button {
    box-sizing: border-box;
    padding: 1em;
}