:root {
    --bg: #f4f1ea;
    --surface: #ffffff;
    --surface-2: #f8f6f1;
    --text: #23211d;
    --muted: #6d675c;
    --border: #e2ddd2;
    --accent: #7a5a2f;
    --accent-strong: #5e4421;
    --accent-soft: #f1e7d6;
    --ok: #2f7d4f;
    --ok-soft: #e3f3e8;
    --bad: #b23b32;
    --bad-soft: #fbe6e3;
    --warn: #9a6a00;
    --warn-soft: #fff3d6;
    --shadow: 0 1px 2px rgba(0,0,0,.06), 0 4px 16px rgba(0,0,0,.05);
    --radius: 12px;
    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #171614;
        --surface: #22201d;
        --surface-2: #2a2824;
        --text: #ece7de;
        --muted: #a39b8d;
        --border: #3a3631;
        --accent: #d2a764;
        --accent-strong: #e6bf81;
        --accent-soft: #3a3024;
        --ok: #6cc28f;
        --ok-soft: #1f3327;
        --bad: #ef7d73;
        --bad-soft: #3d2320;
        --warn: #e5b74e;
        --warn-soft: #3a311c;
        --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.3);
        color-scheme: dark;
    }
}

* { box-sizing: border-box; }

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

a { color: var(--accent); }

button, input, select {
    font: inherit;
    color: inherit;
}

/* ---------- top bar ---------- */
.topbar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 20px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
}
.brand {
    font-weight: 700;
    font-size: 18px;
    text-decoration: none;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
}
.brand .logo { font-size: 24px; color: var(--accent); }
.topbar .spacer { flex: 1; }
.topbar .who { color: var(--muted); font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 14px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    cursor: pointer;
    text-decoration: none;
    color: var(--text);
    white-space: nowrap;
    transition: background .15s, border-color .15s;
}
.btn:hover { background: var(--surface-2); }
.btn:disabled { opacity: .5; cursor: default; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: var(--accent-strong); }
@media (prefers-color-scheme: dark) { .btn.primary { color: #1b1712; } }
.btn.ghost { background: transparent; border-color: transparent; }
.btn.ghost:hover { background: var(--surface-2); }
.btn.small { padding: 4px 10px; font-size: 13px; }
.btn.danger { color: var(--bad); }
.btn.active { background: var(--accent-soft); border-color: var(--accent); }

/* ---------- layout ---------- */
.page { max-width: 1180px; margin: 0 auto; padding: 24px 20px 60px; }

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
}

h1 { font-size: 26px; margin: 0 0 4px; }
h2 { font-size: 18px; margin: 0 0 12px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }

input[type=text], input[type=email], input[type=password], input[type=url], select {
    width: 100%;
    padding: 10px 12px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface-2);
}
input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
label { display: block; font-size: 13px; color: var(--muted); margin: 10px 0 4px; }

.error-box { color: var(--bad); background: var(--bad-soft); border-radius: 8px; padding: 8px 12px; margin-top: 10px; }
.hidden { display: none !important; }

/* ---------- login ---------- */
.login-wrap { min-height: 100vh; display: grid; place-items: center; padding: 16px; }
.login-card { width: 100%; max-width: 380px; }
.login-card .brand { justify-content: center; font-size: 22px; margin-bottom: 4px; }
.login-card .btn { width: 100%; margin-top: 16px; }

/* ---------- home ---------- */
.hero { margin-bottom: 20px; }
.new-form { display: flex; gap: 10px; margin-top: 14px; }
.new-form input { flex: 1; min-width: 0; }

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
    margin-top: 20px;
}
.tcard {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}
.tcard .thumb {
    aspect-ratio: 16 / 9;
    background: var(--surface-2) center / cover no-repeat;
    position: relative;
}
.tcard .thumb .duration {
    position: absolute; right: 8px; bottom: 8px;
    background: rgba(0,0,0,.75); color: #fff; font-size: 12px; padding: 1px 6px; border-radius: 4px;
}
.tcard .body { padding: 12px 14px; flex: 1; display: flex; flex-direction: column; gap: 6px; }
.tcard .title { font-weight: 600; line-height: 1.3; }
.tcard .actions { display: flex; gap: 6px; flex-wrap: wrap; margin-top: auto; padding-top: 6px; }

.badge {
    display: inline-block; font-size: 12px; font-weight: 600; padding: 2px 8px; border-radius: 99px;
    background: var(--surface-2); color: var(--muted);
}
.badge.ready { background: var(--ok-soft); color: var(--ok); }
.badge.failed { background: var(--bad-soft); color: var(--bad); }
.badge.running { background: var(--warn-soft); color: var(--warn); }

.progress { height: 6px; border-radius: 99px; background: var(--surface-2); overflow: hidden; }
.progress > div { height: 100%; background: var(--accent); transition: width .5s; }

.empty { text-align: center; padding: 40px 10px; color: var(--muted); }
.empty .big { font-size: 48px; }

/* ---------- dialog ---------- */
dialog {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text);
    padding: 20px;
    width: min(520px, calc(100vw - 32px));
    box-shadow: var(--shadow);
}
dialog::backdrop { background: rgba(0,0,0,.4); }
dialog .row { display: flex; gap: 10px; }
dialog .row > * { flex: 1; }
dialog .dialog-actions { display: flex; justify-content: flex-end; gap: 8px; margin-top: 16px; }
.user-list { list-style: none; padding: 0; margin: 0 0 12px; max-height: 240px; overflow: auto; }
.user-list li { display: flex; align-items: center; gap: 8px; padding: 6px 0; border-bottom: 1px solid var(--border); }
.user-list li span:first-child { flex: 1; overflow: hidden; text-overflow: ellipsis; }

/* ---------- tutorial player ---------- */
.player {
    display: grid;
    grid-template-columns: minmax(0, 560px) minmax(0, 1fr);
    gap: 20px;
    align-items: start;
}
@media (max-width: 900px) {
    .player { grid-template-columns: minmax(0, 1fr); }
}

.board-col { display: flex; flex-direction: column; gap: 12px; }
.board-wrap { width: 100%; aspect-ratio: 1; position: relative; }
.board-wrap .cg-wrap { width: 100%; height: 100%; }
.board-wrap.shake { animation: shake .35s; }
@keyframes shake {
    20%, 60% { transform: translateX(-6px); }
    40%, 80% { transform: translateX(6px); }
}

.prompt {
    border-radius: 10px;
    padding: 12px 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    min-height: 74px;
}
.prompt .head { font-weight: 700; display: flex; align-items: center; gap: 8px; }
.prompt.your-move { border-color: var(--accent); background: var(--accent-soft); }
.prompt.correct { border-color: var(--ok); background: var(--ok-soft); }
.prompt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.prompt.done { border-color: var(--ok); background: var(--ok-soft); }
.prompt .expl { margin-top: 4px; }

.controls { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.controls .sep { flex: 1; }
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.seg button { border: 0; background: var(--surface); padding: 6px 12px; cursor: pointer; }
.seg button + button { border-left: 1px solid var(--border); }
.seg button.on { background: var(--accent); color: #fff; }
@media (prefers-color-scheme: dark) { .seg button.on { color: #1b1712; } }

.side-col { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.video { aspect-ratio: 16 / 9; width: 100%; border-radius: var(--radius); overflow: hidden; background: #000; }
.video iframe, .video > div { width: 100%; height: 100%; border: 0; }

.lines { list-style: none; margin: 0; padding: 0; }
.lines li {
    display: flex; align-items: center; gap: 10px;
    padding: 8px 10px; border-radius: 8px; cursor: pointer;
}
.lines li:hover { background: var(--surface-2); }
.lines li.current { background: var(--accent-soft); }
.lines .check {
    width: 22px; height: 22px; border-radius: 50%; flex: none;
    border: 2px solid var(--border); display: grid; place-items: center; font-size: 12px; color: transparent;
}
.lines li.complete .check { background: var(--ok); border-color: var(--ok); color: #fff; }
.lines .lt { flex: 1; min-width: 0; }
.lines .lt div:first-child { font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.moves { display: flex; flex-wrap: wrap; gap: 2px 4px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 14px; }
.moves .num { color: var(--muted); margin-left: 6px; }
.moves .mv { padding: 1px 5px; border-radius: 4px; cursor: pointer; }
.moves .mv.setup { color: var(--muted); }
.moves .mv.hidden-move { color: transparent; background: var(--surface-2); user-select: none; }
.moves .mv.current { background: var(--accent); color: #fff; }
.moves .mv:hover:not(.hidden-move) { background: var(--accent-soft); }

.summary-text { white-space: pre-line; }
.warnings { font-size: 13px; color: var(--warn); }
.progress-line { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); }
.progress-line .progress { flex: 1; }

/* Chessground: subtle "your move" hint circles use the brand colour */
cg-board square.move-dest { background: radial-gradient(rgba(20, 85, 30, 0.45) 22%, transparent 0); }
cg-board square.oc.move-dest { background: radial-gradient(transparent 0%, transparent 79%, rgba(20, 85, 0, 0.35) 80%); }

@media (max-width: 560px) {
    .page { padding: 16px 16px 40px; }
    .topbar { padding: 8px 16px; }
    .topbar .who { display: none; }
    .new-form { flex-direction: column; }
    h1 { font-size: 22px; }
}