body {
    font-family: 'Merriweather', serif;
    background-color: #f5f5f5;
    color: #333333;
    font-size: 16px;
}

.othello-content {
    max-width: 900px;
    margin: 0 auto 12px;
    padding: 0;
    border: 0;
    background: transparent;
    box-shadow: none;
}

.navbar-left {
    float: left !important;
    margin-left: -14px;
}

.navbar-brand {
    margin-right: 20px;
    color: #f5f5f5 !important;
    font-family: 'Oswald', sans-serif;
    font-size: 24px;
}

.navbar-nav > li > a {
    color: #c0c0c0 !important;
}

.navbar-nav > .active > a {
    color: #ffffff !important;
}

.navbar {
    margin-bottom: 0;
}

.playground-heading {
    position: static !important;
    top: auto !important;
    z-index: auto !important;
    max-width: 900px;
    margin: 0 auto -60px;
    padding: 20px 0 0;
    border: 0;
    background: transparent;
    box-shadow: none;
}

.playground-heading h1 {
    margin: 1px 0 8px;
    font-size: 36px;
}

.playground-heading p:last-child {
    margin: 0;
    font-size: 16px;
    line-height: 1.35;
}

.back-link {
    margin: 0;
    font-size: 15px;
}

.back-link a {
    color: #333333;
}

.game-area {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.play-surface {
    --board-size: min(calc(48vh + 10px), 450px, calc(100vw - 30px));
    display: grid;
    grid-template-columns: var(--board-size) minmax(0, 170px);
    gap: 16px;
    justify-content: center;
    width: 100%;
}

.board-stage {
    position: relative;
    grid-column: 1;
    grid-row: 1;
    width: var(--board-size);
    aspect-ratio: 1;
}

.agent-configuration {
    display: flex;
    grid-column: 2;
    grid-row: 1;
    flex-direction: column;
    justify-content: space-between;
    min-width: 0;
    height: var(--board-size);
    padding: 14px 12px;
    border: 1px solid #c9cbc8;
    background: rgba(235, 236, 234, 0.54);
    transition: opacity 140ms ease;
}

.agent-configuration.is-locked {
    opacity: 0.5;
}

.configuration-label {
    margin: 0 0 3px;
    color: #777777;
    font-family: Arial, sans-serif;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.agent-configuration h2 {
    margin: 0;
    font-size: 18px;
    line-height: 1.25;
}

.agent-configuration fieldset {
    margin: 14px 0 0;
    padding: 0;
    border: 0;
}

.agent-configuration legend {
    width: auto;
    margin: 0 0 6px;
    border: 0;
    color: #333333;
    font-size: 12px;
    font-weight: 700;
}

.heuristic-options {
    border-top: 1px solid #bfc2bf;
}

.heuristic-options label {
    position: relative;
    display: block;
    margin: 0;
    border-bottom: 1px solid #bfc2bf;
    cursor: pointer;
}

.heuristic-options input,
.depth-options input,
.custom-depth-choice input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.heuristic-options span {
    display: block;
    padding: 6px 7px;
    color: #565656;
    font-size: 12px;
    line-height: 1.25;
}

.heuristic-options input:checked + span {
    padding-left: 18px;
    background: #3f4541;
    color: #ffffff;
}

.heuristic-options input:checked + span::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 7px;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: #ffffff;
    transform: translateY(-50%);
}

.depth-options {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    border-top: 1px solid #bfc2bf;
    border-left: 1px solid #bfc2bf;
}

.depth-options label {
    position: relative;
    margin: 0;
    border-right: 1px solid #bfc2bf;
    border-bottom: 1px solid #bfc2bf;
    cursor: pointer;
}

.depth-options span {
    display: block;
    padding: 6px 2px;
    color: #565656;
    font-family: Arial, sans-serif;
    font-size: 12px;
    text-align: center;
}

.depth-options input:checked + span {
    background: #3f4541;
    color: #ffffff;
}

.custom-depth-control {
    display: grid;
    grid-template-columns: 1fr 1fr;
    margin-top: 7px;
    border: 1px solid #bfc2bf;
}

.custom-depth-choice {
    position: relative;
    display: flex;
    align-items: stretch;
    margin: 0;
    border-right: 1px solid #bfc2bf;
    cursor: pointer;
}

.custom-depth-choice span {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 5px 3px;
    color: #565656;
    font-size: 10px;
}

.custom-depth-choice input:checked + span {
    background: #3f4541;
    color: #ffffff;
}

.custom-depth-input-label {
    display: flex;
    flex-direction: column;
    gap: 2px;
    margin: 0;
    padding: 3px 4px 4px;
}

.custom-depth-input-label span {
    color: #777777;
    font-family: Arial, sans-serif;
    font-size: 8px;
    line-height: 1;
    text-align: center;
}

.custom-depth-input-label input {
    width: 100%;
    height: 21px;
    padding: 1px 3px;
    border: 1px solid #bfc2bf;
    border-radius: 0;
    background: #f5f5f5;
    color: #333333;
    font-family: Arial, sans-serif;
    font-size: 11px;
    text-align: center;
}

.custom-depth-input-label input:focus-visible {
    border-color: #337ab7;
    outline: 1px solid #337ab7;
}

.heuristic-options input:focus-visible + span,
.depth-options input:focus-visible + span,
.custom-depth-choice input:focus-visible + span {
    outline: 2px solid #337ab7;
    outline-offset: -2px;
}

.heuristic-options input:disabled + span,
.depth-options input:disabled + span,
.custom-depth-choice input:disabled + span {
    cursor: default;
}

.configuration-help {
    margin: 7px 0 0;
    color: #777777;
    font-size: 10px;
    line-height: 1.45;
}

.board-frame {
    width: 100%;
    height: 100%;
    padding: 5px;
    border: 1px solid #aeb3af;
    background: #c8cdc9;
}

.othello-board {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    width: 100%;
    height: 100%;
    border-top: 1px solid #b2b8b3;
    border-left: 1px solid #b2b8b3;
    background: #d9ddda;
}

.board-cell {
    position: relative;
    min-width: 0;
    padding: 0;
    border: 0;
    border-right: 1px solid #b2b8b3;
    border-bottom: 1px solid #b2b8b3;
    border-radius: 0;
    background: #d9ddda;
    appearance: none;
    cursor: default;
}

.board-cell.legal-move {
    cursor: pointer;
}

.board-cell.legal-move::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 16%;
    aspect-ratio: 1;
    border: 1px solid #68736c;
    border-radius: 50%;
    background: #8d9991;
    transform: translate(-50%, -50%);
}

.board-cell.legal-move:hover,
.board-cell.legal-move:focus-visible {
    background: #cdd3cf;
    outline: 2px solid #337ab7;
    outline-offset: -2px;
    z-index: 2;
}

.disc {
    position: absolute;
    top: 12%;
    left: 12%;
    width: 76%;
    height: 76%;
    border-radius: 50%;
    pointer-events: none;
}

.disc.black {
    border: 1px solid #1a1a1a;
    background: #303030;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.24);
}

.disc.white {
    border: 1px solid #c0c0bc;
    background: #f7f7f3;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.16);
}

.board-cell.last-move::before {
    content: '';
    position: absolute;
    inset: 6%;
    border: 2px solid #337ab7;
    pointer-events: none;
    z-index: 1;
}

.board-overlay {
    position: absolute;
    inset: 0;
    z-index: 4;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
    background: rgba(100, 104, 101, 0.52);
}

.board-overlay[hidden] {
    display: none;
}

.board-dialog {
    width: min(330px, 82%);
    padding: 18px 20px;
    border: 1px solid #aaaead;
    background: #f5f5f5;
    box-shadow: 0 8px 22px rgba(0, 0, 0, 0.16);
    text-align: left;
}

.board-dialog h2 {
    margin: 0 0 5px;
    font-size: 22px;
}

.board-dialog > p {
    margin: 0 0 12px;
    color: #606060;
    font-size: 12px;
    line-height: 1.5;
}

.board-dialog fieldset {
    margin: 0 0 12px;
    padding: 0;
    border: 0;
}

.board-dialog legend {
    width: auto;
    margin: 0 0 5px;
    border: 0;
    color: #333333;
    font-size: 12px;
    font-weight: 700;
}

.option-row {
    display: grid;
    border: 1px solid #b8bbb8;
}

.two-options {
    grid-template-columns: repeat(2, 1fr);
}

.three-options {
    grid-template-columns: repeat(3, 1fr);
}

.option-row label {
    position: relative;
    margin: 0;
    cursor: pointer;
}

.option-row label + label {
    border-left: 1px solid #b8bbb8;
}

.option-row input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.option-row span {
    display: block;
    padding: 7px 5px;
    color: #555555;
    font-size: 12px;
    font-weight: 400;
    text-align: center;
}

.option-row input:checked + span {
    background: #3f4541;
    color: #ffffff;
}

.option-row input:focus-visible + span {
    outline: 2px solid #337ab7;
    outline-offset: -2px;
}

.option-row input:disabled + span {
    color: #969696;
    background: #e2e2df;
}

.primary-game-button,
.new-game-button {
    border: 1px solid #3f4541;
    border-radius: 0;
    background: #3f4541;
    color: #ffffff;
    font-family: 'Merriweather', serif;
    font-size: 12px;
    font-weight: 700;
}

.primary-game-button {
    width: 100%;
    padding: 8px 12px;
}

.primary-game-button:hover,
.primary-game-button:focus-visible,
.new-game-button:hover,
.new-game-button:focus-visible {
    background: #282c29;
    color: #ffffff;
    outline: 2px solid #337ab7;
    outline-offset: 2px;
}

.dialog-label {
    margin-bottom: 3px !important;
    color: #777777 !important;
    font-family: Arial, sans-serif;
    font-size: 10px !important;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.final-score {
    color: #333333 !important;
    font-weight: 700;
}

.game-toolbar {
    display: flex;
    align-items: stretch;
    width: min(900px, 100%);
    min-height: 48px;
    margin-top: 15px;
    border-top: 1px solid #c9cbc8;
    border-bottom: 1px solid #c9cbc8;
}

.score-item,
.turn-status,
.locked-settings {
    display: flex;
    align-items: center;
    padding: 4px 10px;
}

.score-item {
    min-width: 112px;
    justify-content: space-between;
    gap: 10px;
}

.score-item + .score-item {
    border-left: 1px solid #dededb;
}

.score-color {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
}

.score-color small {
    color: #777777;
    font-size: 10px;
}

.score-item strong {
    font-family: Arial, sans-serif;
    font-size: 19px;
}

.score-disc {
    width: 14px;
    height: 14px;
    border-radius: 50%;
}

.black-disc {
    border: 1px solid #222222;
    background: #303030;
}

.white-disc {
    border: 1px solid #bdbdb8;
    background: #f7f7f3;
}

.turn-status {
    flex: 1;
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    min-width: 190px;
    border-right: 1px solid #dededb;
    border-left: 1px solid #dededb;
}

.turn-status strong {
    font-size: 13px;
}

.turn-status span {
    overflow: hidden;
    max-width: 290px;
    color: #6f6f6f;
    font-size: 10px;
    line-height: 1.4;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.locked-settings {
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    min-width: 106px;
    color: #898989;
    font-size: 10px;
    line-height: 1.5;
}

.new-game-button {
    align-self: center;
    margin: 0 8px;
    padding: 6px 9px;
    white-space: nowrap;
}

.research-note {
    width: min(900px, 100%);
    max-width: 900px;
    margin: -60px auto 0;
    padding: 2px 0 0;
    border-top: 0;
    line-height: 1.5;
}

.research-note h2 {
    display: inline;
    margin: 0 8px 0 0;
    font-size: 18px;
}

.research-note p {
    display: inline;
    margin: 0;
    font-size: 14px;
}

.noscript-message {
    margin-top: 10px;
    padding: 10px;
    border: 1px solid #ad4c4c;
    background: #fff4f4;
}

@media (max-width: 800px) {
    .play-surface {
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 12px;
    }

    .agent-configuration {
        order: 2;
        width: min(100%, 520px);
        height: auto;
    }

    .heuristic-options {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        border-left: 1px solid #bfc2bf;
    }

    .heuristic-options label {
        border-right: 1px solid #bfc2bf;
    }

    .heuristic-options span {
        min-height: 100%;
        padding: 7px 3px;
        text-align: center;
    }

    .heuristic-options input:checked + span {
        padding-left: 3px;
    }

    .heuristic-options input:checked + span::before {
        display: none;
    }

    .depth-options {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (max-width: 700px) {
    .othello-content {
        padding: 0 2px;
    }

    .playground-heading {
        width: 100%;
    }

    .game-toolbar {
        flex-wrap: wrap;
        width: 100%;
    }

    .turn-status {
        order: -1;
        flex-basis: 100%;
        border-right: 0;
        border-bottom: 1px solid #dededb;
        border-left: 0;
    }

    .score-item {
        flex: 1;
    }

    .locked-settings {
        display: none;
    }

    .research-note {
        width: 100%;
    }
}

@media (max-width: 430px) {
    .playground-heading p:last-child {
        font-size: 15px;
    }

    .board-dialog {
        width: 86%;
        padding: 13px 15px;
    }

    .board-dialog fieldset {
        margin-bottom: 9px;
    }

    .new-game-button {
        margin-left: 0;
    }
}