:root {
    --bg:           #080416;
    --surface:      rgba(18, 12, 50, 0.5);
    --surface-2:    rgba(10, 7, 30, 0.6);
    --border:       rgba(255, 255, 255, 0.08);
    --accent:       #f5a623;
    --accent-dark:  #d4891a;
    --purple:       #7c3aed;
    --text:         #f0f4ff;
    --muted:        #8892b0;
    --success:      #22c55e;
    --warning:      #f97316;
    --danger:       #ef4444;
    --tile-result:  #0ea5e9;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background:
        radial-gradient(ellipse 80% 60% at 10% 5%,  rgba(124, 58, 237, 0.22) 0%, transparent 100%),
        radial-gradient(ellipse 70% 70% at 90% 95%, rgba(245, 166, 35, 0.1)  0%, transparent 100%),
        radial-gradient(ellipse 50% 80% at 50% 50%, rgba(15, 8, 45, 1)       0%, rgba(8, 4, 22, 1) 100%);
    background-attachment: fixed;
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* ── Header ── */
header {
    width: 100%;
    background: rgba(8, 4, 22, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(245, 166, 35, 0.25);
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
    padding: 0.875rem 1rem;
    text-align: center;
}
header h1 {
    font-size: clamp(1.75rem, 7vw, 2.75rem);
    font-weight: 900;
    letter-spacing: 0.18em;
    background: linear-gradient(135deg, #fbbf24 0%, #f5a623 50%, #fb923c 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-transform: uppercase;
    filter: drop-shadow(0 0 20px rgba(245, 166, 35, 0.5));
}
header p {
    font-size: 0.8rem;
    color: var(--muted);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-top: 0.1rem;
}

/* ── Screens ── */
.screen { display: none; width: 100%; max-width: min(580px, 56.25vh); padding: 1.25rem 1rem 2rem; }
.screen.active { display: block; }

/* ── Setup ── */
.setup-card {
    background: var(--surface);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow:
        0 8px 32px rgba(0, 0, 0, 0.45),
        inset 0 1px 0 rgba(255, 255, 255, 0.06),
        0 0 0 1px rgba(124, 58, 237, 0.12);
}
.setup-card h2 {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    margin-bottom: 1rem;
}
.big-choices {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 0.5rem;
}
.duration-choices {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
}
.choice-btn {
    padding: 0 0.25rem;
    height: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(50, 35, 110, 0.7);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.22);
    color: var(--text);
    border-radius: 10px;
    font-size: 1.1rem;
    font-weight: 800;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s, color 0.15s, box-shadow 0.15s;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}
.choice-btn:hover { border-color: rgba(245, 166, 35, 0.6); box-shadow: 0 0 14px rgba(245, 166, 35, 0.18), 0 2px 8px rgba(0, 0, 0, 0.4); }
.choice-btn.selected {
    background: linear-gradient(135deg, #f59e0b, #f5a623, #fb923c);
    border-color: transparent;
    color: #000;
    box-shadow: 0 0 22px rgba(245, 166, 35, 0.45), 0 4px 12px rgba(245, 166, 35, 0.2);
}
[data-duration="0"] { font-size: clamp(1.2rem, 5.8vw, 1.8rem); }
[data-duration="0"] .inf-glyph { display: inline-block; transform: translateY(-0.12em); }
@media (min-width: 480px) {
    [data-duration="0"] .inf-glyph { transform: translateY(-0.02em); }
}

.target-range-option {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.range-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.6rem;
}

.range-reset-btn {
    background: none;
    border: none;
    color: var(--muted);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    padding: 0;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.range-reset-btn:hover { color: var(--text); }

.range-row {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 0.45rem;
}

.range-bound-label {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    width: 2rem;
    flex-shrink: 0;
}

.range-choices {
    display: flex;
    gap: 0.4rem;
    flex: 1;
}

.range-btn {
    flex: 1;
    max-width: 2.8rem;
    height: 2.4rem;
    font-size: 0.85rem;
    padding: 0 0.1rem;
}

.range-btn:disabled {
    opacity: 0.25;
    cursor: not-allowed;
    border-color: rgba(255, 255, 255, 0.06) !important;
    background: rgba(10, 7, 30, 0.55) !important;
    color: var(--text) !important;
    box-shadow: none !important;
}

.infinity-option {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.solvable-toggle {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    user-select: none;
}
.solvable-toggle input[type="checkbox"] { display: none; }
.toggle-track {
    width: 44px;
    height: 24px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    position: relative;
    transition: background 0.2s;
    flex-shrink: 0;
}
.toggle-track::after {
    content: '';
    position: absolute;
    top: 3px; left: 3px;
    width: 18px; height: 18px;
    background: var(--muted);
    border-radius: 50%;
    transition: transform 0.2s, background 0.2s;
}
.solvable-toggle input:checked + .toggle-track { background: var(--accent); }
.solvable-toggle input:checked + .toggle-track::after { transform: translateX(20px); background: #000; }
.toggle-label { font-size: 0.9rem; font-weight: 600; color: var(--text); }
.solvable-toggle:has(input:disabled) { opacity: 0.4; cursor: not-allowed; }

.pool-hint {
    font-size: 0.78rem;
    color: var(--muted);
    margin-top: 0.75rem;
    line-height: 1.5;
}
.pool-hint span { color: var(--text); font-weight: 600; }

.start-btn {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, #f59e0b, #f5a623, #fb923c);
    color: #000;
    border: none;
    border-radius: 12px;
    font-size: 1.15rem;
    font-weight: 900;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    cursor: pointer;
    transition: filter 0.15s, box-shadow 0.15s, opacity 0.15s;
    box-shadow: 0 4px 24px rgba(245, 166, 35, 0.4), 0 0 0 1px rgba(245, 166, 35, 0.2);
}
.start-btn:hover:not(:disabled) {
    filter: brightness(1.1);
    box-shadow: 0 6px 32px rgba(245, 166, 35, 0.55), 0 0 0 1px rgba(245, 166, 35, 0.3);
}
.start-btn:disabled { opacity: 0.35; cursor: not-allowed; box-shadow: none; }

/* ── Game header ── */
.game-top {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
}
.target-box, .timer-box {
    background: var(--surface);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 0.75rem 1rem;
    text-align: center;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.06);
}
.target-box {
    border-color: rgba(245, 166, 35, 0.3);
    box-shadow:
        0 0 32px rgba(245, 166, 35, 0.1),
        0 4px 16px rgba(0, 0, 0, 0.35),
        inset 0 1px 0 rgba(255, 255, 255, 0.06);
}
.box-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    margin-bottom: 0.2rem;
}
.target-number {
    font-size: clamp(2.25rem, 10vw, 3.5rem);
    font-weight: 900;
    color: var(--accent);
    line-height: 1;
    text-shadow: 0 0 32px rgba(245, 166, 35, 0.45);
}
.timer-value {
    font-size: clamp(1.75rem, 8vw, 2.75rem);
    font-weight: 900;
    line-height: 1;
    color: var(--text);
    transition: color 0.3s;
    min-width: 2.5ch;
}
.timer-value.warn  { color: var(--warning); text-shadow: 0 0 16px rgba(249, 115, 22, 0.4); }
.timer-value.crit  { color: var(--danger); text-shadow: 0 0 16px rgba(239, 68, 68, 0.4); animation: pulse 0.5s infinite alternate; }

@keyframes pulse   { to { opacity: 0.5; } }
@keyframes shake   { 0%,100%{transform:translateX(0)} 20%{transform:translateX(-6px)} 60%{transform:translateX(6px)} 80%{transform:translateX(-3px)} }
@keyframes pop-in  { 0%{transform:scale(0.4);opacity:0} 65%{transform:scale(1.12)} 100%{transform:scale(1);opacity:1} }

/* ── Timer progress bar ── */
.timer-bar {
    height: 5px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 3px;
    margin-bottom: 0.875rem;
    overflow: hidden;
}
.timer-bar-fill {
    height: 100%;
    width: 100%;
    background: linear-gradient(90deg, var(--purple), var(--accent));
    border-radius: 3px;
    transition: width 1s linear, background 0.3s;
    box-shadow: 0 0 8px rgba(245, 166, 35, 0.5);
}

/* ── Tiles ── */
.tiles-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 0.5rem;
    margin-bottom: 0.875rem;
}
.tile {
    position: relative;
    aspect-ratio: 1;
    background: rgba(18, 12, 50, 0.65);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: clamp(1rem, 4vw, 1.5rem);
    font-weight: 900;
    cursor: pointer;
    transition: transform 0.12s, border-color 0.12s, background 0.12s, box-shadow 0.12s, opacity 0.2s;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.07);
}
.tile:hover:not(.used):not(.disabled-game):not(.dim) {
    border-color: rgba(245, 166, 35, 0.55);
    transform: translateY(-3px);
    box-shadow: 0 0 18px rgba(245, 166, 35, 0.2), 0 6px 16px rgba(0, 0, 0, 0.35);
}
.tile.selected {
    background: linear-gradient(135deg, #f59e0b, #f5a623, #fb923c);
    border-color: transparent;
    color: #000;
    transform: translateY(-4px);
    box-shadow: 0 0 28px rgba(245, 166, 35, 0.6), 0 8px 20px rgba(245, 166, 35, 0.25);
}
.tile.is-result {
    background: rgba(14, 165, 233, 0.15);
    border-color: rgba(14, 165, 233, 0.4);
    color: var(--tile-result);
}
.tile.is-result:hover:not(.used):not(.dim) {
    border-color: rgba(56, 189, 248, 0.7);
    box-shadow: 0 0 18px rgba(14, 165, 233, 0.2), 0 6px 16px rgba(0, 0, 0, 0.35);
}
.tile.is-result.selected {
    background: linear-gradient(135deg, #f59e0b, #f5a623, #fb923c);
    border-color: transparent;
    color: #000;
}
.tile.used         { opacity: 0.12; cursor: not-allowed; pointer-events: none; }
.tile.disabled-game { cursor: not-allowed; }
.tile.dim          { opacity: 0.25; cursor: not-allowed; }
.tile.shake        { animation: shake 0.4s ease; }
.tile.pop-in       { animation: pop-in 0.32s ease; }
.tile-key {
    position: absolute;
    top: 3px; right: 5px;
    font-size: 0.55rem;
    font-weight: 700;
    color: var(--muted);
    line-height: 1;
    pointer-events: none;
}

/* ── Operators ── */
.operators {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-bottom: 0.875rem;
}
.op-btn {
    padding: 0.7rem 0.25rem;
    background: rgba(50, 35, 110, 0.7);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.22);
    color: var(--text);
    border-radius: 10px;
    font-size: 1.4rem;
    font-weight: 700;
    cursor: pointer;
    transition: border-color 0.12s, background 0.12s, color 0.12s, opacity 0.15s, box-shadow 0.12s;
    -webkit-tap-highlight-color: transparent;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}
.op-btn:hover:not(:disabled) {
    border-color: rgba(245, 166, 35, 0.6);
    box-shadow: 0 0 14px rgba(245, 166, 35, 0.18), 0 2px 8px rgba(0, 0, 0, 0.4);
}
.op-btn.selected {
    background: rgba(10, 7, 30, 0.75);
    border-color: rgba(245, 166, 35, 0.6);
    color: var(--accent);
    box-shadow: 0 0 18px rgba(245, 166, 35, 0.2);
}
.op-btn:disabled { opacity: 0.25; cursor: not-allowed; }

/* ── Expression display ── */
.expr-display {
    background: rgba(10, 7, 30, 0.6);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 10px;
    padding: 0.75rem 1rem;
    text-align: center;
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--muted);
    min-height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 0.625rem;
    transition: color 0.15s;
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.03);
}
.expr-display.active { color: var(--text); }

/* ── Error ── */
.error-banner {
    background: rgba(45, 11, 11, 0.85);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(239, 68, 68, 0.4);
    color: var(--danger);
    border-radius: 8px;
    padding: 0.5rem 0.875rem;
    font-size: 0.875rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0.625rem;
    opacity: 0;
    transition: opacity 0.2s;
    pointer-events: none;
}
.error-banner.visible { opacity: 1; }

/* ── Working history ── */
.working {
    background: rgba(10, 7, 30, 0.55);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.06);
    border-radius: 10px;
    padding: 0.875rem;
    margin-bottom: 0.875rem;
    min-height: 76px;
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
}
.working-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    margin-bottom: 0.5rem;
}
.steps-list { list-style: none; display: flex; flex-direction: column; gap: 0.3rem; }
.steps-list li {
    font-size: 0.9rem;
    padding: 0.3rem 0.625rem;
    background: rgba(18, 12, 50, 0.55);
    border-radius: 6px;
    border-left: 3px solid transparent;
}
.steps-list li.step-success {
    color: var(--success);
    border-left-color: var(--success);
}
.closest-display {
    margin-top: 0.5rem;
    font-size: 0.8rem;
    color: var(--muted);
    min-height: 1.1rem;
}
.closest-display.exact  { color: var(--success); font-weight: 700; }
.closest-display.close  { color: var(--warning); font-weight: 600; }
.closest-display.far    { color: var(--muted); }

/* ── Action buttons ── */
.actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
}
.infinity-mode .actions { grid-template-columns: 1fr 1fr 1fr; }
.act-btn {
    padding: 0.875rem 0.5rem;
    border-radius: 10px;
    font-size: 0.925rem;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.15s;
    border: 1px solid transparent;
    -webkit-tap-highlight-color: transparent;
}
.btn-undo, .btn-reset {
    background: rgba(50, 35, 110, 0.7);
    backdrop-filter: blur(8px);
    color: var(--text);
    border-color: rgba(255, 255, 255, 0.22);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}
.btn-undo:hover:not(:disabled)  { border-color: rgba(255, 255, 255, 0.25); }
.btn-reset:hover:not(:disabled) { border-color: rgba(239, 68, 68, 0.5); color: var(--danger); }
.btn-quit {
    display: none;
    background: rgba(50, 35, 110, 0.7);
    backdrop-filter: blur(8px);
    color: var(--muted);
    border-color: rgba(255, 255, 255, 0.18);
}
.infinity-mode .btn-quit { display: block; }
.btn-quit:hover:not(:disabled) { border-color: rgba(239, 68, 68, 0.5); color: var(--danger); }
.act-btn:disabled { opacity: 0.25; cursor: not-allowed; }

/* ── Infinity mode ── */
.infinity-mode .timer-bar { display: none; }

/* ── Confirmation modal ── */
.modal-overlay[hidden] { display: none; }
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(4, 2, 14, 0.75);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: 1rem;
}
.modal-card {
    background: rgba(18, 12, 50, 0.88);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: 2rem 1.5rem;
    max-width: 320px;
    width: 100%;
    text-align: center;
    box-shadow:
        0 20px 60px rgba(0, 0, 0, 0.6),
        0 0 0 1px rgba(124, 58, 237, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.08);
}
.modal-title {
    font-size: 1.2rem;
    font-weight: 900;
    color: var(--text);
    margin-bottom: 0.5rem;
}
.modal-body {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 1.5rem;
}
.modal-btns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
}
.modal-btn {
    padding: 0.875rem 0.5rem;
    border-radius: 10px;
    font-size: 0.925rem;
    font-weight: 800;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all 0.15s;
}
.modal-cancel {
    background: rgba(50, 35, 110, 0.7);
    color: var(--text);
    border-color: rgba(255, 255, 255, 0.22);
}
.modal-cancel:hover { border-color: rgba(255, 255, 255, 0.4); }
.modal-confirm {
    background: var(--danger);
    color: #fff;
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.35);
}
.modal-confirm:hover { filter: brightness(1.15); }

/* ── Result screen numbers grid ── */
#result-numbers {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}
.result-tile {
    aspect-ratio: 1;
    background: rgba(18, 12, 50, 0.65);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: clamp(1rem, 4vw, 1.5rem);
    font-weight: 900;
}

/* ── Result screen ── */
.result-card {
    background: var(--surface);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 1.25rem 1.5rem;
    margin-bottom: 0.875rem;
    box-shadow:
        0 8px 32px rgba(0, 0, 0, 0.45),
        inset 0 1px 0 rgba(255, 255, 255, 0.06),
        0 0 0 1px rgba(124, 58, 237, 0.12);
}
.result-card h2 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    margin-bottom: 0.75rem;
}
.verdict {
    font-size: 1.35rem;
    font-weight: 900;
    margin-bottom: 0.75rem;
    line-height: 1.3;
}
.v-exact  { color: var(--success); text-shadow: 0 0 20px rgba(34, 197, 94, 0.4); }
.v-close  { color: var(--warning); text-shadow: 0 0 16px rgba(249, 115, 22, 0.3); }
.v-miss   { color: var(--danger); }
.v-none   { color: var(--muted); }
.result-steps { list-style: none; display: flex; flex-direction: column; gap: 0.35rem; }
.result-steps.two-col {
    display: grid;
    grid-template-rows: repeat(3, auto);
    grid-auto-flow: column;
    grid-auto-columns: 1fr;
    align-items: start;
}
.result-steps li {
    font-size: 0.9rem;
    padding: 0.35rem 0.75rem;
    background: rgba(18, 12, 50, 0.55);
    border-radius: 6px;
}
.no-steps { color: var(--muted); font-style: italic; font-size: 0.9rem; }
.computer-summary {
    font-size: 0.875rem;
    color: var(--muted);
    margin-bottom: 0.5rem;
}

.result-actions {
    display: flex;
    gap: 0.75rem;
}

.play-again-btn {
    flex: 2;
    padding: 1rem;
    background: linear-gradient(135deg, #f59e0b, #f5a623, #fb923c);
    color: #000;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    cursor: pointer;
    transition: filter 0.15s, box-shadow 0.15s;
    box-shadow: 0 4px 24px rgba(245, 166, 35, 0.4);
}
.play-again-btn:hover {
    filter: brightness(1.1);
    box-shadow: 0 6px 32px rgba(245, 166, 35, 0.55);
}

.options-btn {
    flex: 1;
    padding: 1rem;
    background: rgba(50, 35, 110, 0.7);
    backdrop-filter: blur(8px);
    color: var(--text);
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    cursor: pointer;
    transition: border-color 0.15s, box-shadow 0.15s;
}
.options-btn:hover { border-color: rgba(245, 166, 35, 0.4); box-shadow: 0 0 14px rgba(245, 166, 35, 0.12); }

/* ── Responsive tweaks ── */
@media (max-width: 380px) {
    .tile { border-radius: 7px; }
}