/* ── FEN block ──────────────────────────────────────────────────────── */
.fen-block {
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    gap: 0.375rem;
}
.fen-input-wrap {
    position: relative;
    width: 100%;
    display: flex;
    align-items: center;
    gap: var(--fen-row-gap);
}
.fen-input-wrap__label {
    position: absolute;
    left: 0.625rem; top: 50%;
    transform: translateY(-50%);
    font-size: var(--text-xs); font-weight: 700;
    letter-spacing: 0.16em; text-transform: uppercase;
    color: var(--text-muted);
    pointer-events: none; user-select: none; z-index: 1;
}
.fen-input {
    flex: 1 1 auto;
    min-width: 0;
    width: auto;
    height: var(--control-h);
    padding: 0 0.625rem 0 2.75rem;
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    color: var(--text);
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: var(--r-md);
    outline: none;
    letter-spacing: 0.02em;
    transition: border-color var(--tr), box-shadow var(--tr);
}
.fen-input:focus { border-color: var(--gold-dim); box-shadow: 0 0 0 2px var(--gold-glow); }
.fen-input::placeholder { color: var(--text-muted); font-size: var(--text-xs); }
.fen-input.is-invalid {
    border-color: var(--loss) !important;
    box-shadow: 0 0 0 2px rgba(248,113,113,0.15) !important;
}

.fen-actions {
    display: flex;
    gap: var(--fen-row-gap);
    flex-wrap: nowrap;
}

/* Lock button - sits beside the FEN input, height matched to it. Width comes
   from the FEN-row rule below. .lock-icon is drawn in a 0.6875rem layout box
   and scaled up to its 0.875rem appearance at paint time. .is-locked uses
   the same gold border/background as other active controls. */
.btn--lock {
    height: var(--control-h);
}

/* Lock, Back and Next share one fixed width from --fen-icon-btn-w,
   independent of icon size and padding. Scoped to the FEN row; other
   icon-only buttons size from their own padding. */
.fen-input-wrap > .btn--lock,
.fen-actions > .btn--icon-only {
    flex: 0 0 var(--fen-icon-btn-w);
    width: var(--fen-icon-btn-w);
    padding: 0;
    justify-content: center;
}
.btn--lock .lock-icon {
    width: 0.6875rem;
    height: 0.6875rem;
    transform: scale(1.2727);
}
.btn--lock.is-locked {
    border-color: var(--gold);
    color: var(--gold);
    background: var(--gold-glow);
}
.btn--lock.is-locked:hover:not(.is-autoplay-disabled) { background: var(--gold-glow); border-color: var(--gold); }
.btn--lock.is-locked .btn__icon { opacity: 1; }
/* Soft-disabled during an auto-play run - see lockAutoplayDisabled in
   FenBar.jsx. Uses a class/aria-disabled rather than the native disabled
   attribute so the button stays hoverable. */
.btn--lock.is-autoplay-disabled { opacity: 0.38; cursor: not-allowed; }
/* Two icons are always present; CSS toggles which is visible via .is-locked. */
.lock-icon--unlocked { display: block; }
.lock-icon--locked   { display: none; }
.btn--lock.is-locked .lock-icon--unlocked { display: none; }
.btn--lock.is-locked .lock-icon--locked   { display: block; }

/* Spare-piece trays - dimmed while locked. Kept clickable (not
   pointer-events:none) so they still show a not-allowed cursor; the
   actual placement is refused at the source in board.js. */
.spare-tray.is-locked { opacity: 0.35; }
.spare-tray.is-locked .spare-piece { cursor: not-allowed; }

/* ── Error / coverage line ──────────────────────────────────────────── */
.error-line {
    flex-shrink: 0;
    min-height: 0.875rem;
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--loss);
    padding-left: 0.125rem;
    display: flex;
    align-items: center;
    gap: 0.3125rem;
    line-height: 1.4;
}
.error-line:empty { visibility: hidden; }
.error-line.is-coverage-error { color: var(--amber); }

/* ── Turn toggle ────────────────────────────────────────────────────── */
.turn-row { display: flex; gap: 0.3125rem; }
.turn-btn {
    flex: 1;
    height: var(--control-h);
    display: flex; align-items: center; justify-content: center; gap: 0.375rem;
    border-radius: var(--r-md);
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--text-dim);
    font-size: var(--text-xs); font-weight: 600;
    font-family: var(--font-ui);
    letter-spacing: 0.03em;
    cursor: pointer;
    transition: background var(--tr), border-color var(--tr), color var(--tr);
    user-select: none;
}
.turn-btn:hover { background: var(--surface-3); border-color: var(--border-2); color: var(--text); }
.turn-btn:active { transform: scale(0.97); }
.turn-pip {
    width: 0.5rem; height: 0.5rem;
    border-radius: 50%;
    flex-shrink: 0;
    transition: background var(--tr), box-shadow var(--tr);
}
.turn-pip--w { background: var(--board-light); border: 1.5px solid var(--board-dark); }
.turn-pip--b { background: var(--pip-black-bg); border: 1.5px solid var(--pip-black-border); }
.turn-btn.is-active {
    background: var(--turn-active-bg);
    border-color: var(--gold-dim);
    color: var(--gold);
}
.turn-btn.is-active .turn-pip--w { box-shadow: 0 0 5px color-mix(in srgb, var(--board-light) 50%, transparent); }
.turn-btn.is-active .turn-pip--b { border-color: var(--text-dim); }