:root {
    color-scheme: dark light;
    --bg: #0f172a;
    --panel: #111827;
    --panel-border: #1f2937;
    --text: #f8fafc;
    --muted: #cbd5f5;
    --accent: #f97316;
    --accent-glow: rgba(249, 115, 22, 0.4);
    --success: #4ade80;
    --error: #f87171;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
    background: radial-gradient(circle at top, #1e293b 0%, var(--bg) 45%, #020617 100%);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 32px 16px 48px;
}

.logic-container {
    width: min(980px, 100%);
    background: rgba(9, 16, 28, 0.85);
    border-radius: 18px;
    border: 1px solid rgba(148, 163, 184, 0.2);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.35);
    padding: 32px;
    backdrop-filter: blur(18px);
}

.logic-header {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 24px;
}

.logic-header h1 {
    margin: 0;
    font-size: clamp(1.8rem, 3vw, 2.2rem);
    letter-spacing: 0.02em;
}

.tagline {
    margin: 6px 0 0;
    color: var(--muted);
    font-size: 1rem;
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

.scoreboard {
    font-size: 1.1rem;
    font-weight: 600;
    padding: 6px 16px;
    border-radius: 999px;
    background: rgba(148, 163, 184, 0.15);
    border: 1px solid rgba(148, 163, 184, 0.25);
}

.auto-advance-toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
    background: rgba(148, 163, 184, 0.12);
    border-radius: 999px;
    padding: 4px 14px;
    border: 1px solid rgba(148, 163, 184, 0.25);
    cursor: pointer;
}

.auto-advance-toggle input {
    transform: scale(1.2);
}

.toolbar-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border-radius: 999px;
    border: 1px solid rgba(249, 115, 22, 0.6);
    color: var(--text);
    text-decoration: none;
    background: rgba(249, 115, 22, 0.15);
    box-shadow: 0 0 12px var(--accent-glow);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.toolbar-link:hover {
    transform: translateY(-1px);
    box-shadow: 0 0 18px rgba(249, 115, 22, 0.55);
}

.challenge-section {
    background: rgba(15, 23, 42, 0.8);
    border-radius: 16px;
    padding: 24px;
    border: 1px solid rgba(148, 163, 184, 0.2);
}

.challenge-header {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 24px;
}

.challenge-header h2 {
    margin: 0;
    font-size: clamp(1.4rem, 2.5vw, 1.7rem);
}

.gate-description {
    margin: 6px 0 0;
    color: var(--muted);
}

.gate-info {
    display: flex;
    align-items: baseline;
    gap: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.challenge-body {
    display: grid;
    grid-template-columns: minmax(240px, 1fr) minmax(280px, 1.25fr);
    gap: 32px;
    align-items: center;
}

.gate-diagram {
    width: 100%;
    min-height: 220px;
    background: linear-gradient(155deg, rgba(15, 23, 42, 0.8), rgba(17, 24, 39, 0.95));
    border-radius: 18px;
    border: 1px solid rgba(148, 163, 184, 0.18);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 12px;
}

.gate-diagram svg {
    width: 100%;
    height: auto;
    max-width: 240px;
    filter: drop-shadow(0 0 18px rgba(249, 115, 22, 0.4));
}

.truth-table-wrapper {
    overflow-x: auto;
}

.truth-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 1.1rem;
    border-radius: 14px;
    overflow: hidden;
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
}

.truth-table caption {
    padding: 12px 16px;
    background: rgba(30, 41, 59, 0.9);
    color: var(--muted);
    text-align: left;
    font-size: 1rem;
}

.truth-table th,
.truth-table td {
    padding: 14px 18px;
    text-align: center;
    border-bottom: 1px solid rgba(148, 163, 184, 0.2);
}

.truth-table th {
    background: rgba(30, 41, 59, 0.75);
    font-size: 1rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.truth-table tbody tr:nth-child(odd) {
    background: rgba(30, 41, 59, 0.35);
}

.truth-table tbody tr:nth-child(even) {
    background: rgba(15, 23, 42, 0.55);
}

.truth-table tbody tr:nth-child(odd) td {
    border-bottom: 1px solid rgba(46, 60, 92, 0.4);
}

.truth-table input[type="text"] {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    border: 2px solid rgba(148, 163, 184, 0.55);
    background: rgba(15, 23, 42, 0.85);
    color: var(--text);
    font-size: 1.6rem;
    text-align: center;
    transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.1s ease;
}

.truth-table input[type="text"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 4px rgba(249, 115, 22, 0.2);
    transform: scale(1.02);
}

.truth-table input[type="text"][aria-invalid="true"] {
    border-color: var(--error);
    box-shadow: 0 0 0 3px rgba(248, 113, 113, 0.25);
}

.truth-table input[type="text"].correct {
    border-color: var(--success);
    box-shadow: 0 0 0 3px rgba(74, 222, 128, 0.25);
    background: rgba(22, 101, 52, 0.3);
}

.controls {
    margin-top: 28px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 16px;
}

button {
    cursor: pointer;
    border: none;
    background: linear-gradient(135deg, rgba(249, 115, 22, 0.9), rgba(248, 134, 77, 0.9));
    color: #0f172a;
    font-size: 1.05rem;
    font-weight: 600;
    padding: 14px 28px;
    border-radius: 999px;
    box-shadow: 0 18px 28px rgba(249, 115, 22, 0.35);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

button:hover {
    transform: translateY(-1px);
    box-shadow: 0 22px 30px rgba(249, 115, 22, 0.45);
}

button:active {
    transform: translateY(0);
}

button:disabled {
    cursor: not-allowed;
    opacity: 0.7;
    box-shadow: none;
}

.feedback {
    min-height: 24px;
    margin-top: 12px;
    font-size: 1rem;
    color: var(--muted);
}

.feedback.success {
    color: var(--success);
}

.feedback.error {
    color: var(--error);
}

.resources {
    margin-top: 32px;
    background: rgba(15, 23, 42, 0.65);
    border-radius: 14px;
    border: 1px solid rgba(148, 163, 184, 0.18);
    padding: 20px 24px;
}

.resources h2 {
    margin-top: 0;
}

.resources ul {
    margin: 12px 0 0;
    padding-left: 20px;
    color: var(--muted);
    font-size: 0.98rem;
    line-height: 1.6;
}

@media (max-width: 900px) {
    body {
        padding: 24px 12px 40px;
    }

    .logic-container {
        padding: 24px;
    }

    .challenge-body {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}