:root {
    --paper: #f3efe5;
    --paper-deep: #e7e0d1;

    --ink: #20221d;
    --ink-soft: #575a51;

    --forest: #20392f;
    --forest-deep: #172a23;
    --forest-soft: #64786c;

    --brass: #a6884f;
    --brass-light: #c4ac79;

    --border: #cfc7b6;

    --board-light: #e8dfcc;
    --board-dark: #637263;

    --white: #fffdf7;
}

* {
    box-sizing: border-box;
}

html {
    background: var(--paper);
}

body {
    margin: 0;

    color: var(--ink);
    background:
        linear-gradient(
            180deg,
            #f7f4ec 0%,
            var(--paper) 100%
        );

    font-family:
        Inter,
        ui-sans-serif,
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;

    min-height: 100vh;
}

.page {
    width: min(1180px, calc(100% - 40px));
    margin: 0 auto;
    padding: 72px 0 120px;
}


/* ---------- Header ---------- */

.hero {
    border-top: 1px solid var(--brass);
    padding-top: 24px;
    margin-bottom: 50px;
}

.eyebrow {
    margin: 0 0 18px;

    color: var(--forest);

    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.22em;
    text-transform: uppercase;
}

h1 {
    max-width: 820px;
    margin: 0;

    font-family:
        Baskerville,
        "Iowan Old Style",
        "Palatino Linotype",
        Georgia,
        serif;

    font-size: clamp(2.8rem, 6vw, 5.6rem);
    font-weight: 400;
    line-height: 0.98;
    letter-spacing: -0.035em;

    color: var(--forest-deep);
}

.lead {
    max-width: 680px;
    margin: 26px 0 0;

    color: var(--ink-soft);

    font-family:
        Georgia,
        serif;

    font-size: 1.05rem;
    line-height: 1.75;
}


/* ---------- Generic panels ---------- */

.upload-card,
.game-info,
.position-card {
    background: rgba(255, 253, 247, 0.76);

    border: 1px solid var(--border);
    box-shadow:
        0 1px 0 rgba(255,255,255,0.7) inset,
        0 16px 40px rgba(45, 39, 27, 0.06);
}

.upload-card {
    padding: 30px;
}

.game-info {
    margin-top: 34px;
    padding: 20px 26px;
}


/* ---------- Form ---------- */

form {
    display: grid;
    grid-template-columns: 1.25fr 1fr auto;
    align-items: end;
    gap: 22px;
}

.form-row {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

label {
    color: var(--forest-deep);
    font-size: 0.9rem;
    font-weight: 650;
}

small {
    color: #77776e;
}

input,
textarea {
    font: inherit;
}

input {
    width: 100%;

    padding: 12px 13px;

    color: var(--ink);
    background: var(--white);

    border: 1px solid var(--border);
    border-radius: 3px;

    outline: none;
}

input:focus,
textarea:focus {
    border-color: var(--brass);
    box-shadow: 0 0 0 2px rgba(166, 136, 79, 0.12);
}


/* ---------- Buttons ---------- */

button {
    padding: 12px 18px;

    border: 1px solid var(--forest-deep);
    border-radius: 3px;

    color: var(--white);
    background: var(--forest);

    font: inherit;
    font-size: 0.9rem;
    font-weight: 650;
    letter-spacing: 0.01em;

    cursor: pointer;

    transition:
        background 120ms ease,
        transform 120ms ease;
}

button:hover {
    background: var(--forest-deep);
}

button:active {
    transform: translateY(1px);
}

button:disabled {
    cursor: wait;
    opacity: 0.5;
}


/* ---------- Status ---------- */

.status {
    margin-top: 20px;
    color: var(--ink-soft);
}

.status.error {
    color: #8b3c37;
}

.hidden {
    display: none;
}


/* ---------- Game ---------- */

.game-title {
    font-family:
        Baskerville,
        Georgia,
        serif;

    color: var(--forest-deep);

    font-size: 1.45rem;
}

.game-meta {
    margin-top: 7px;

    color: var(--ink-soft);
    font-size: 0.85rem;
}


/* ---------- Positions ---------- */

.positions {
    display: flex;
    flex-direction: column;
    gap: 46px;

    margin-top: 42px;
}

.position-card {
    padding: 32px;
}

.position-header {
    display: flex;
    justify-content: space-between;
    align-items: end;

    padding-bottom: 20px;
    margin-bottom: 28px;

    border-bottom: 1px solid var(--border);
}

.position-number {
    color: var(--brass);

    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.18em;
    text-transform: uppercase;
}

.position-title {
    margin-top: 7px;

    color: var(--forest-deep);

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 2rem;
    font-weight: 400;
}

.position-layout {
    display: grid;

    grid-template-columns:
        minmax(320px, 500px)
        minmax(320px, 1fr);

    gap: 44px;

    align-items: start;
}


/* ---------- Chess board ---------- */

.board {
    display: grid;
    grid-template-columns: repeat(8, minmax(0, 1fr));
    grid-template-rows: repeat(8, minmax(0, 1fr));

    width: 100%;
    aspect-ratio: 1 / 1;

    overflow: hidden;

    border: 1px solid #5c6258;
    box-shadow:
        0 12px 28px rgba(39, 43, 35, 0.14);
}

.square {
    position: relative;

    display: flex;
    align-items: center;
    justify-content: center;

    min-width: 0;
    min-height: 0;

    overflow: hidden;
}

.square.light {
    background: var(--board-light);
}

.square.dark {
    background: var(--board-dark);
}

.piece {
    display: block;

    width: 86%;
    height: 86%;

    object-fit: contain;

    user-select: none;
    pointer-events: none;
}


/* ---------- Analysis ---------- */

.analysis-panel {
    padding-top: 4px;
}

.question {
    margin-bottom: 26px;
}

.question label {
    display: block;
    margin-bottom: 9px;

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.08rem;
    font-weight: 600;
}

.analysis-panel textarea {
    width: 100%;
    min-height: 115px;

    padding: 14px 15px;

    resize: vertical;

    color: var(--ink);
    background: rgba(255,255,255,0.65);

    border: 1px solid var(--border);
    border-radius: 3px;

    line-height: 1.5;
}

.reveal-button {
    margin-top: 2px;
}


/* ---------- Engine result ---------- */

.engine-details {
    margin-top: 26px;
    padding: 20px;

    background: var(--forest-deep);
    color: var(--white);

    border-top: 3px solid var(--brass);
}

.engine-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.engine-label {
    color: #babfb8;

    font-size: 0.7rem;
    font-weight: 650;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.engine-value {
    margin-top: 5px;

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.35rem;
}


/* ---------- Responsive ---------- */

@media (max-width: 850px) {

    .page {
        width: min(100% - 24px, 680px);
        padding-top: 40px;
    }

    form {
        grid-template-columns: 1fr;
    }

    .position-layout {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .position-card {
        padding: 20px;
    }

    .engine-grid {
        grid-template-columns: 1fr;
    }
}


/* ---------- Training workspace ---------- */

.training-workspace {
    margin-top: 42px;
}


/* ---------- Position tabs ---------- */

.position-tabs {
    display: flex;
    gap: 0;

    margin-bottom: 18px;

    border-bottom: 1px solid var(--border);
}

.position-tab {
    display: flex;
    align-items: baseline;
    gap: 10px;

    padding: 13px 22px 14px;

    color: var(--ink-soft);
    background: transparent;

    border: 0;
    border-bottom: 2px solid transparent;
    border-radius: 0;

    font-weight: 500;
}

.position-tab:hover {
    color: var(--forest-deep);
    background: transparent;
}

.position-tab.active {
    color: var(--forest-deep);
    background: transparent;

    border-bottom-color: var(--brass);
}

.tab-roman {
    color: var(--brass);

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.2rem;
}

.tab-move {
    font-size: 0.8rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}


/* ---------- Active position ---------- */

.active-card {
    margin: 0;
}

.position-counter {
    color: var(--ink-soft);

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.2rem;
}

.board-column {
    width: 100%;
}

.board-caption {
    margin-top: 10px;

    color: var(--ink-soft);

    font-size: 0.72rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}


/* ---------- Analysis intro ---------- */

.analysis-intro {
    margin-bottom: 30px;
    padding-bottom: 22px;

    border-bottom: 1px solid var(--border);
}

.analysis-kicker {
    margin-bottom: 8px;

    color: var(--brass);

    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.analysis-intro p {
    max-width: 520px;

    margin: 0;

    color: var(--ink-soft);

    font-family:
        Baskerville,
        Georgia,
        serif;

    line-height: 1.6;
}


/* ---------- Actions ---------- */

.analysis-actions {
    display: flex;
    justify-content: flex-start;

    margin-top: 4px;
}


/* ---------- Engine comparison ---------- */

.engine-section-title {
    margin-bottom: 22px;

    color: var(--brass-light);

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.4rem;
}

.engine-item {
    padding-bottom: 4px;
}


/* ---------- Related errors ---------- */

.related-errors {
    margin-top: 28px;
    padding-top: 20px;

    border-top: 1px solid rgba(255,255,255,0.14);
}

.related-errors ul {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 18px;

    margin: 12px 0 0;
    padding: 0;

    list-style: none;
}

.related-errors li {
    display: flex;
    gap: 6px;

    color: #d7d9d4;

    font-size: 0.85rem;
}

.related-errors li span {
    color: #9fa59e;
}


/* ---------- Position navigation ---------- */

.position-navigation {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;

    margin-top: 34px;
    padding-top: 24px;

    border-top: 1px solid var(--border);
}

.position-navigation > div:last-child {
    text-align: right;
}

.secondary-button {
    color: var(--forest);
    background: transparent;

    border-color: var(--forest);
}

.secondary-button:hover {
    color: var(--white);
    background: var(--forest);
}

.analysis-complete {
    color: var(--brass);

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.05rem;
}


/* ---------- Mobile ---------- */

@media (max-width: 650px) {

    .position-tabs {
        overflow-x: auto;
    }

    .position-tab {
        flex: 0 0 auto;
        padding-left: 14px;
        padding-right: 14px;
    }

    .position-navigation {
        gap: 14px;
    }

    .position-navigation button {
        width: 100%;
    }

}


/* =========================================================
   GAME LIBRARY
   ========================================================= */

.game-library {
    margin-top: 42px;
}

.library-header {
    display: flex;
    justify-content: space-between;
    align-items: end;
    gap: 30px;

    margin-bottom: 22px;
}

.library-header h2,
.notation-heading h2,
.analysis-loading h2 {
    margin: 5px 0 0;

    font-family:
        Baskerville,
        Georgia,
        serif;

    color: var(--forest-deep);

    font-size: 2rem;
    font-weight: 400;
}

.library-kicker {
    color: var(--brass);

    font-size: 0.68rem;
    font-weight: 700;

    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.library-note {
    color: var(--ink-soft);
    font-size: 0.82rem;
}


.game-list {
    border-top: 1px solid var(--border);
}

.game-row {
    display: grid;

    grid-template-columns:
        50px
        minmax(0, 1fr)
        60px
        110px;

    width: 100%;

    padding: 17px 12px;

    align-items: center;

    color: var(--ink);
    background: transparent;

    border: 0;
    border-bottom: 1px solid var(--border);
    border-radius: 0;

    text-align: left;
}

.game-row:hover {
    background:
        rgba(255,255,255,0.5);

    color: var(--ink);
}

.game-row-number {
    color: var(--brass);

    font-family:
        Baskerville,
        Georgia,
        serif;
}

.game-row-players {
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
    gap: 7px;
}

.game-row-players small {
    color: var(--ink-soft);
}

.game-dash {
    color: var(--border);
}

.game-row-meta {
    margin-top: 3px;

    color: var(--ink-soft);

    font-size: 0.75rem;
}

.game-row-result {
    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.1rem;
}

.game-row-action {
    color: var(--forest);

    font-size: 0.78rem;

    text-align: right;
}


/* =========================================================
   ANALYSIS LOADING
   ========================================================= */

.analysis-loading {
    max-width: 760px;

    margin: 64px auto;
    padding: 44px 0;
}

.analysis-loading-kicker {
    color: var(--brass);

    font-size: 0.68rem;
    font-weight: 700;

    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.analysis-loading p {
    margin-top: 22px;

    color: var(--ink-soft);
}

.progress-track {
    width: 100%;
    height: 5px;

    margin-top: 30px;

    overflow: hidden;

    background:
        var(--paper-deep);
}

.progress-bar {
    height: 100%;

    background:
        var(--forest);

    transition:
        width 180ms linear;
}

.progress-footer {
    display: flex;
    justify-content: space-between;

    margin-top: 10px;

    color: var(--ink-soft);

    font-size: 0.72rem;
}


/* =========================================================
   NOTATION WORKSPACE
   ========================================================= */

.notation-workspace {
    display: grid;

    grid-template-columns:
        minmax(420px, 1.1fr)
        minmax(330px, 0.9fr);

    gap: 46px;

    margin-top: 42px;

    align-items: start;
}

.board-pane {
    min-width: 0;
}

.notation-pane {
    min-width: 0;

    padding-left: 30px;

    border-left:
        1px solid var(--border);
}

.notation-heading {
    display: flex;
    justify-content: space-between;
    align-items: start;

    margin-bottom: 24px;
}


/* =========================================================
   MAIN NOTATION
   ========================================================= */

.main-notation {
    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: 1.03rem;
    line-height: 1.8;
}

.notation-row {
    display: grid;

    grid-template-columns:
        36px
        minmax(70px, auto)
        minmax(70px, auto);

    align-items: baseline;

    column-gap: 4px;
}

.move-number {
    color: var(--ink-soft);

    font-size: 0.76rem;
}

.notation-move {
    display: inline-flex;
    align-items: center;
    gap: 5px;

    justify-self: start;

    padding: 2px 5px;

    color: var(--ink);
    background: transparent;

    border: 0;
    border-radius: 2px;

    font-family: inherit;
    font-size: inherit;
    font-weight: 400;
}

.notation-move:hover {
    color: var(--forest-deep);

    background:
        rgba(166,136,79,0.09);
}

.notation-move.active-move {
    background:
        var(--forest);

    color: var(--white);
}


/* =========================================================
   CRITICAL MOVES
   ========================================================= */

.critical-move {
    color: var(--forest-deep);

    font-weight: 700;
}

.critical-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;

    min-width: 19px;
    height: 19px;

    padding: 0 4px;

    color: var(--white);
    background: var(--brass);

    border-radius: 50%;

    font-family:
        Inter,
        system-ui,
        sans-serif;

    font-size: 0.58rem;
    font-weight: 700;
}


/* =========================================================
   ENGINE VARIATIONS
   ========================================================= */

.critical-variations {
    grid-column:
        2 / -1;

    margin:
        5px 0
        13px 10px;

    padding:
        8px 0
        8px 13px;

    border-left:
        1px solid var(--brass-light);
}

.engine-line {
    margin-bottom: 7px;

    color: var(--ink-soft);

    font-size: 0.84rem;
    line-height: 1.55;
}

.engine-line:last-child {
    margin-bottom: 0;
}

.engine-line-head {
    display: flex;
    gap: 6px;
    align-items: baseline;
}

.engine-line-head strong {
    color: var(--forest-deep);
}

.engine-score {
    margin-left: auto;

    color: var(--brass);

    font-family:
        Inter,
        system-ui,
        sans-serif;

    font-size: 0.72rem;
}

.engine-pv {
    margin-top: 2px;
}

.engine-pv-move {
    display: inline;

    padding: 1px 2px;

    color: var(--ink-soft);
    background: transparent;

    border: 0;

    font-family:
        Baskerville,
        Georgia,
        serif;

    font-size: inherit;
    font-weight: 400;
}

.engine-pv-move:hover {
    color: var(--forest-deep);
    background: transparent;

    text-decoration: underline;
}

.pv-number {
    color: #9a968d;

    font-size: 0.8em;
}


/* =========================================================
   BOARD NAVIGATION
   ========================================================= */

.board-navigation {
    display: flex;
    align-items: center;
    gap: 15px;

    margin-top: 14px;
    padding-bottom: 12px;

    border-bottom:
        1px solid var(--border);
}

.user-variation {
    margin-top: 20px;
}


/* =========================================================
   MOBILE
   ========================================================= */

@media (max-width: 900px) {

    .notation-workspace {
        grid-template-columns: 1fr;
    }

    .notation-pane {
        padding-left: 0;

        border-left: 0;
        border-top:
            1px solid var(--border);

        padding-top: 28px;
    }

}


@media (max-width: 650px) {

    .game-row {
        grid-template-columns:
            35px
            minmax(0,1fr)
            50px;
    }

    .game-row-action {
        display: none;
    }

    .library-header {
        align-items: start;
        flex-direction: column;
        gap: 8px;
    }

    .progress-footer {
        gap: 10px;
        flex-direction: column;
    }

}


/* ---------- Evaluation after each move ---------- */

.notation-move {
    gap: 5px;
}

.move-san {
    white-space: nowrap;
}

.move-eval {
    margin-left: 3px;

    color: #9a8661;

    font-family:
        Inter,
        system-ui,
        sans-serif;

    font-size: 0.65rem;
    font-weight: 500;

    font-variant-numeric:
        tabular-nums;

    opacity: 0.82;
}

.notation-move.active-move
.move-eval {
    color: #d8c8a5;
}

.critical-move
.move-eval {
    color: var(--brass);
}