:root {
    --accent-color: #ff8888;
    --accent-strong: color-mix(in srgb, var(--accent-color) 85%, white 15%);
    --accent-soft: color-mix(in srgb, var(--accent-color) 40%, white 10%);
    --accent-glow: color-mix(in srgb, var(--accent-color) 35%, transparent);
    --accent-shadow: color-mix(in srgb, var(--accent-color) 25%, black 45%);

    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.78);
    --bg-dark-overlay: rgba(0, 0, 0, 0.55);
    --content-bg: rgba(255, 255, 255, 0.06);

    --correct-color: #49ffc2;
    --wrong-color: #ff6b6b;

    --radius-ui: 24px;
}

body,
html {
    margin: 0;
    font-family: "Noto Sans TC", "Inter", sans-serif;
    color: var(--text-primary);
    background: #000;
    overflow-y: overlay;
    background-color: transparent;
}

.full-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -2;
    overflow: hidden;
}

.full-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: brightness(60%) grayscale(18%) blur(2px);
    transform: scale(1.03);
}

.full-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background:
        linear-gradient(180deg, color-mix(in srgb, var(--accent-color) 8%, transparent), transparent 40%),
        var(--bg-dark-overlay);
    z-index: -1;
}

.main-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    box-sizing: border-box;
}

.hidden {
    display: none !important;
}

.content-card {
    background: var(--content-bg);
    backdrop-filter: blur(8px);
    border-radius: var(--radius-ui);
    padding: 30px;
    box-shadow: 0 2px 15px color-mix(in srgb, var(--accent-color) 16%, transparent);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.15);
}

.content-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 26px color-mix(in srgb, var(--accent-color) 35%, transparent);
}

#start-screen {
    text-align: center;
    max-width: 650px;
}

.mode-selection {
    display: flex;
    gap: 20px;
    margin-top: 20px;
}

.mode-card {
    flex: 1;
    padding: 20px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 16px;
    background: rgba(0, 0, 0, 0.2);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.mode-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px color-mix(in srgb, var(--accent-color) 25%, transparent);
}

.mode-card h2 {
    color: var(--accent-strong);
    margin-top: 0;
}

.mode-card p {
    color: var(--text-secondary);
    flex-grow: 1;
}

.custom-mode-setup {
    margin: 15px 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
    align-items: center;
}

.custom-mode-setup label {
    font-size: 0.9em;
    color: var(--text-secondary);
}

.custom-mode-setup input {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.15);
    color: white;
    padding: 8px;
    border-radius: 12px;
    width: 100px;
    text-align: center;
    font-family: inherit;
}

.flex-layout {
    display: flex;
    gap: 40px;
    justify-content: center;
    align-items: stretch;
    width: 100%;
    max-width: 900px;
}

#game-area,
#qa-area {
    flex: 1;
}

#game-area {
    text-align: center;
}

#plinko-canvas {
    background: #000;
    border-radius: var(--radius-ui);
    border: 2px solid var(--accent-strong);
    display: block;
    margin: 0 auto 15px;
    box-shadow: 0 0 25px var(--accent-glow);
}

.game-controls p {
    color: var(--text-secondary);
}

#chips-display {
    font-weight: 700;
    font-size: 1.2em;
    color: var(--accent-strong);
}

#ball-result {
    color: var(--accent-soft);
    min-height: 1.2em;
}

#qa-area {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

#qa-area h2 {
    color: var(--accent-strong);
    text-shadow: 0 0 10px var(--accent-glow);
    margin-top: 0;
}

#question-text {
    color: var(--text-secondary);
    min-height: 60px;
}

.options {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin: 20px 0;
}

button {
    padding: 12px 24px;
    margin: 10px 0;
    border-radius: 12px;
    border: none;
    background: var(--accent-strong);
    color: #1a1a1a;
    font-size: 1em;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s, background 0.2s, box-shadow 0.2s;
}

button:hover:not(:disabled) {
    background: color-mix(in srgb, var(--accent-color) 95%, white 5%);
    transform: translateY(-3px);
    box-shadow: 0 6px 16px var(--accent-shadow);
}

button:disabled {
    background: #4a4a4a;
    color: #888;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.options button {
    padding: 12px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
    font-weight: 600;
    backdrop-filter: blur(10px) saturate(160%);
    text-align: left;
    border: 1px solid transparent;
}

.options button:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-3px);
    box-shadow: 0 6px 16px var(--accent-shadow);
}

.options button.selected {
    border-color: var(--accent-strong);
    background: var(--accent-soft);
    color: #fff;
}

.options button.correct {
    background: var(--correct-color);
    color: #000;
    border-color: var(--correct-color);
}

.options button.wrong {
    background: var(--wrong-color);
    color: #fff;
    border-color: var(--wrong-color);
    opacity: 0.7;
}

#result-text {
    margin-top: 20px;
    font-weight: 600;
    min-height: 50px;
    color: var(--accent-strong);
    text-shadow: 0 0 12px var(--accent-glow);
}

#timer-display {
    position: absolute;
    top: 20px;
    right: 30px;
    font-size: 1.5em;
    font-weight: 800;
    color: var(--accent-strong);
    background: rgba(0, 0, 0, 0.3);
    padding: 5px 15px;
    border-radius: 12px;
    transition: color 0.3s ease, transform 0.3s ease;
    text-shadow: 0 0 10px var(--accent-glow);
}

#timer-display.low-time {
    color: var(--wrong-color);
    transform: scale(1.1);
}

.action-buttons {
    display: flex;
    gap: 10px;
    align-items: center;
}

#answer-question-btn {
    flex-grow: 1;
}

#wager-btn {
    padding: 12px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-secondary);
    border: 1px solid transparent;
    transition: background 0.2s, border-color 0.2s;
}

#wager-btn.active {
    background: var(--accent-soft);
    border-color: var(--accent-strong);
    color: #fff;
    box-shadow: 0 0 15px var(--accent-glow);
}

#item-shop {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: 5px;
}

.item-btn {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    font-size: 0.9em;
    padding: 8px 15px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.item-btn:hover:not(:disabled) {
    background: var(--accent-soft);
    color: #fff;
    transform: translateY(-3px);
    box-shadow: 0 6px 16px var(--accent-shadow);
}

#end-screen {
    text-align: center;
    max-width: 450px;
}

@media (max-width: 768px) {
    .flex-layout {
        flex-direction: column;
        align-items: center;
    }

    #game-area,
    #qa-area {
        width: 100%;
        max-width: 450px;
    }

    .mode-selection {
        flex-direction: column;
    }
}

::-webkit-scrollbar {
    width: 10px;
    background: transparent;
}

::-webkit-scrollbar-track {
    background: transparent !important;
}

::-webkit-scrollbar-thumb {
    background-color: rgba(255, 255, 255, 0.12);
    border-radius: 999px;
    border: 2px solid transparent;
    background-clip: padding-box;
}

::-webkit-scrollbar-thumb:hover {
    background-color: rgba(255, 255, 255, 0.25);
}

html {
    scrollbar-width: thin;
    scrollbar-color: rgba(255, 255, 255, 0.2) transparent;
}