:root {
    --bg: #05050d;
    --panel: #111839;
    --line: #4e67ad;
    --text: #edf3ff;
    --muted: #9cafdf;
    --cyan: #64efff;
    --magenta: #ff6fd0;
    --amber: #ffd875;
    --good: #8dffbf;
    --bad: #ff7e99;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    padding: 1rem;
    display: flex;
    justify-content: center;
    color: var(--text);
    font-family: "Inter", "Segoe UI", system-ui, sans-serif;
    background:
        radial-gradient(circle at 12% 9%, rgba(100, 239, 255, 0.2), transparent 40%),
        radial-gradient(circle at 86% 11%, rgba(255, 111, 208, 0.2), transparent 44%),
        linear-gradient(168deg, #05060d 0%, #0a1230 53%, #06050c 100%);
}

.app {
    width: min(980px, 100%);
    display: grid;
    gap: 0.85rem;
}

.panel {
    border: 1px solid var(--line);
    border-radius: 14px;
    background: linear-gradient(180deg, rgba(18, 29, 65, 0.97), rgba(8, 12, 24, 0.96));
    box-shadow: 0 14px 32px rgba(0, 0, 0, 0.38);
}

.topbar {
    padding: 0.95rem 1rem;
}

.back {
    color: var(--amber);
    font-weight: 700;
    text-decoration: none;
}

h1 {
    margin: 0.5rem 0 0.32rem;
    font-size: clamp(1.48rem, 3.3vw, 2.12rem);
}

.topbar p {
    margin: 0;
    color: var(--muted);
}

.stats {
    padding: 0.76rem;
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 0.5rem;
}

.stats > div {
    border: 1px solid #5067ad;
    border-radius: 10px;
    background: rgba(20, 32, 70, 0.72);
    padding: 0.44rem 0.56rem;
}

.k {
    display: block;
    color: var(--muted);
    font-size: 0.71rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.stats strong {
    font-size: 1.04rem;
}

.stage {
    padding: 0.8rem;
    display: grid;
    gap: 0.72rem;
}

.stage-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.8rem;
}

.label {
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-size: 0.7rem;
}

h2 {
    margin: 0.2rem 0 0;
    font-size: clamp(1.05rem, 2.6vw, 1.35rem);
}

.keyboard {
    border: 1px solid #4f64a8;
    border-radius: 12px;
    background: linear-gradient(180deg, #101c43, #0b132a);
    padding: 0.7rem;
    display: grid;
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 0.36rem;
}

.key {
    border: 1px solid #4960a2;
    border-radius: 8px;
    background: linear-gradient(180deg, #1e3168, #15254f);
    min-height: 68px;
    padding: 0.28rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    color: #d5e4ff;
}

.key .n {
    font-size: 0.66rem;
    color: #a8bee9;
}

.key .m {
    text-align: right;
    font-size: 0.72rem;
    color: #c9dcff;
    font-weight: 700;
}

.key.active {
    border-color: #7be9ff;
    background: linear-gradient(180deg, #1dd6ff, #136fe8);
    color: #eaf7ff;
    box-shadow: 0 0 18px rgba(116, 233, 255, 0.45);
}

.key.root {
    border-color: #ffe18a;
    box-shadow: inset 0 0 0 1px rgba(255, 225, 138, 0.45);
}

.answers {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.5rem;
}

button {
    border: 1px solid #5f78c9;
    border-radius: 10px;
    background: #1b316a;
    color: var(--text);
    font-weight: 700;
    padding: 0.56rem 0.8rem;
    cursor: pointer;
}

button:hover:enabled {
    border-color: #9de1ff;
}

button:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

.primary {
    background: linear-gradient(180deg, #15c8ff, #126de0);
    border-color: #7ce3ff;
}

.ghost {
    background: rgba(26, 45, 95, 0.72);
}

.answer {
    min-height: 48px;
    font-size: 0.96rem;
    background: linear-gradient(180deg, #233b79, #182d5c);
}

.answer.correct {
    border-color: #9bffd0;
    box-shadow: 0 0 14px rgba(141, 255, 191, 0.45);
}

.answer.wrong {
    border-color: #ff95ac;
    box-shadow: 0 0 14px rgba(255, 126, 153, 0.42);
}

.hint {
    margin: 0;
    color: var(--muted);
    font-size: 0.88rem;
}

.controls {
    padding: 0.78rem;
    display: grid;
    gap: 0.66rem;
}

.buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.48rem;
}

.message {
    margin: 0;
    border: 1px solid #4e64a8;
    border-radius: 10px;
    min-height: 2.4rem;
    padding: 0.52rem 0.62rem;
    background: rgba(16, 25, 58, 0.72);
    color: #d9e5ff;
}

.message.good {
    color: var(--good);
}

.message.bad {
    color: var(--bad);
}

.message.warn {
    color: var(--amber);
}

@media (max-width: 900px) {
    .stats {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .answers {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 560px) {
    .stats {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .keyboard {
        grid-template-columns: repeat(6, minmax(0, 1fr));
    }

    .stage-head {
        flex-direction: column;
        align-items: stretch;
    }
}