:root {
    color-scheme: light dark;
    --bg: #f6f5f2;
    --surface: #ffffff;
    --text: #1f1f1f;
    --muted: #6b6b6b;
    --border: #dcdad5;
    --accent: #2f6fb3;
    --accent-bg: #dce9f7;
    --comment: #3f7a4a;
    --danger: #b3261e;
    --danger-bg: #fbe4e2;
    --info-bg: #fff4d6;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1b1c1e;
        --surface: #25272a;
        --text: #e6e6e6;
        --muted: #9a9a9a;
        --border: #3a3d41;
        --accent: #7fb2ec;
        --accent-bg: #2c4766;
        --comment: #8cc49a;
        --danger: #f2b8b5;
        --danger-bg: #4a2523;
        --info-bg: #4a3f1f;
    }
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font: 15px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif;
}

button, select {
    font: inherit;
    color: inherit;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 6px;
}

button {
    cursor: pointer;
    padding: 6px 12px;
}

button:hover:not(:disabled) {
    border-color: var(--accent);
}

button:disabled {
    opacity: 0.4;
    cursor: default;
}

/* ---- top bar ---- */

.topbar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 16px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

#picker {
    padding: 6px 10px;
    min-width: 260px;
    max-width: 100%;
}

/* ---- banners ---- */

.banners:empty {
    display: none;
}

.banners {
    padding: 8px 16px 0;
    display: grid;
    gap: 8px;
}

.banner {
    display: flex;
    gap: 12px;
    align-items: flex-start;
    padding: 8px 12px;
    border-radius: 6px;
    background: var(--info-bg);
}

.banner.error {
    background: var(--danger-bg);
    color: var(--danger);
}

.banner p {
    margin: 0;
    flex: 1;
}

.banner button {
    border: none;
    background: transparent;
    padding: 0 4px;
}

/* ---- layout ---- */

.layout {
    display: grid;
    grid-template-columns: minmax(280px, 560px) minmax(280px, 1fr);
    gap: 16px;
    padding: 16px;
    max-width: 1280px;
}

@media (max-width: 820px) {
    .layout {
        grid-template-columns: 1fr;
    }
}

.board {
    width: 100%;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-top: 10px;
}

.hint {
    text-align: center;
    color: var(--muted);
    font-size: 13px;
    margin: 6px 0 0;
}

.side-column {
    display: grid;
    gap: 12px;
    align-content: start;
    min-width: 0;
}

.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 14px;
}

.panel h2 {
    margin: 0 0 6px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
}

.text {
    white-space: pre-wrap;
    overflow-wrap: anywhere;
}

.muted {
    color: var(--muted);
}

/* ---- move tree ---- */

.moves {
    max-height: 40vh;
    overflow-y: auto;
    line-height: 1.8;
}

.moves .line {
    margin: 0;
}

.moves .variations {
    margin: 2px 0 2px 14px;
    padding-left: 10px;
    border-left: 2px solid var(--border);
    font-size: 14px;
}

.move {
    cursor: pointer;
    padding: 1px 3px;
    border-radius: 4px;
    white-space: nowrap;
}

.move:hover {
    background: var(--accent-bg);
}

.move.current {
    background: var(--accent);
    color: var(--surface);
}

.move .number {
    color: var(--muted);
}

.move.current .number {
    color: inherit;
}

/* A small dot marks positions that have their own plan. */
.move.has-plan::after {
    content: "•";
    color: var(--accent);
    margin-left: 1px;
}

.move.current.has-plan::after {
    color: inherit;
}

.inline-comment {
    color: var(--comment);
    font-style: italic;
    margin: 0 4px;
}

.paren {
    color: var(--muted);
}

.paren .move {
    color: var(--text);
}

/* ---- plan and transpositions ---- */

.plan-source:empty {
    display: none;
}

.plan-source {
    font-size: 13px;
    color: var(--muted);
    margin-bottom: 4px;
}

a, .link {
    color: var(--accent);
    cursor: pointer;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.transpositions {
    margin: 0;
    padding-left: 18px;
}

/* ---- editing (M6) ---- */

.spacer {
    flex: 1;
}

.save-status {
    font-size: 13px;
    color: var(--muted);
}

.save-status.error {
    color: var(--danger);
}

button.primary {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--surface);
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid var(--border);
}

.toolbar button,
.nags button {
    padding: 3px 9px;
    font-size: 13px;
}

.nags {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    margin-bottom: 6px;
}

.nags button {
    min-width: 34px;
    font-weight: 600;
}

.nags button.active {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--surface);
}

textarea {
    display: block;
    width: 100%;
    resize: vertical;
    padding: 6px 8px;
    font: inherit;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
}

textarea:focus {
    outline: 2px solid var(--accent-bg);
    border-color: var(--accent);
}

textarea:disabled {
    opacity: 0.6;
}

textarea::placeholder {
    color: var(--muted);
}

.context-menu {
    position: fixed;
    z-index: 10;
    display: grid;
    min-width: 170px;
    padding: 4px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    box-shadow: 0 4px 16px rgb(0 0 0 / 0.18);
}

.context-menu[hidden] {
    display: none;
}

.context-menu button {
    border: none;
    text-align: left;
    padding: 6px 10px;
}

.context-menu button:hover:not(:disabled) {
    background: var(--accent-bg);
}

dialog {
    color: var(--text);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 18px 20px;
    width: min(380px, calc(100vw - 32px));
}

dialog::backdrop {
    background: rgb(0 0 0 / 0.35);
}

dialog h2 {
    margin: 0 0 12px;
    font-size: 17px;
}

dialog label {
    display: grid;
    gap: 4px;
    margin-bottom: 12px;
    font-size: 14px;
}

dialog input,
dialog select {
    font: inherit;
    padding: 6px 8px;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
}

.form-error {
    color: var(--danger);
    margin: 0 0 10px;
}

.dialog-buttons {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
}

/* ---- move-sequence box (M7) ---- */

.find {
    flex: 1;
    max-width: 380px;
}

.find input {
    width: 100%;
    font: inherit;
    padding: 6px 10px;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
}

.find input:focus {
    outline: 2px solid var(--accent-bg);
    border-color: var(--accent);
}

.panel-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
}

.panel-header .close {
    border: none;
    background: transparent;
    padding: 0 4px;
}

.find-list {
    margin: 0;
    padding-left: 18px;
}

.find-results.error .find-list {
    color: var(--danger);
}

@media (max-width: 820px) {
    .topbar {
        flex-wrap: wrap;
    }

    .find {
        order: 1;
        flex-basis: 100%;
        max-width: none;
    }
}

/* ---- accounts (M8) ---- */

.account {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 14px;
}

.account[hidden] {
    display: none;
}

.account-name {
    font-weight: 600;
}

.auth-page .auth-card {
    width: min(380px, calc(100% - 32px));
    margin: 10vh auto 0;
    padding: 24px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
}

.auth-page .topbar + .auth-card {
    margin-top: 6vh;
}

.auth-card h1 {
    margin: 0 0 16px;
    font-size: 20px;
}

.auth-card label,
.add-user label {
    display: grid;
    gap: 4px;
    margin-bottom: 12px;
    font-size: 14px;
}

.auth-card input,
.add-user input:not([type="checkbox"]) {
    font: inherit;
    padding: 6px 8px;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 6px;
}

.auth-card button[type="submit"] {
    width: 100%;
}

.admin {
    display: grid;
    gap: 16px;
    padding: 16px;
    max-width: 760px;
}

.add-user {
    display: grid;
    grid-template-columns: 1fr 1fr auto auto;
    gap: 12px;
    align-items: end;
}

.add-user label {
    margin: 0;
}

.add-user label.checkbox {
    display: flex;
    align-items: center;
    gap: 6px;
    padding-bottom: 8px;
}

@media (max-width: 640px) {
    .add-user {
        grid-template-columns: 1fr;
    }
}

table.users {
    width: 100%;
    border-collapse: collapse;
}

table.users th {
    text-align: left;
    font-size: 13px;
    color: var(--muted);
    font-weight: 600;
}

table.users th,
table.users td {
    padding: 6px 4px;
    border-bottom: 1px solid var(--border);
}

table.users .actions {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    justify-content: flex-end;
}

table.users .actions button {
    padding: 3px 9px;
    font-size: 13px;
}

.banner code {
    font-size: 15px;
    font-weight: 600;
    user-select: all;
}

/* ---- phones and touch screens ---- */

@media (max-width: 640px) {
    .topbar {
        gap: 8px;
        padding: 8px 12px;
    }

    /* Row 1: picker + New + Delete; row 2: move box; row 3: account links. */
    #picker {
        flex: 1 1 0;
        min-width: 0;
    }

    .topbar .spacer {
        display: none;
    }

    .account {
        order: 2;
        flex-basis: 100%;
        gap: 10px;
        font-size: 13px;
    }

    .account button {
        padding: 2px 8px;
        margin-left: auto;
    }

    .layout {
        padding: 12px;
        gap: 12px;
    }

    .admin {
        padding: 12px;
    }
}

/* No keyboard shortcuts without a keyboard; bigger targets for fingers. */
@media (hover: none) and (pointer: coarse) {
    .keys-hint {
        display: none;
    }

    .move {
        padding: 3px 5px;
    }

    .toolbar button,
    .nags button,
    .controls button {
        min-height: 40px;
        min-width: 44px;
    }
}