@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;500;700&display=swap');

:root {
    --bg-color: #050505;
    --card-bg: rgba(255, 255, 255, 0.05);
    --text-primary: #ffffff;
    --text-secondary: #ffffff;
    --accent-color: #ffffff;
    --accent-hover: #ffffff;
    --danger-color: #ff0055;
    --success-color: #00ff9d;
    --glass-border: 1px solid rgba(255, 255, 255, 0.1);
    --glow: 0 0 20px rgba(0, 242, 234, 0.24);
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    background-image:
        radial-gradient(circle at 10% 20%, rgba(0, 242, 234, 0.05) 0%, transparent 20%),
        radial-gradient(circle at 90% 80%, rgba(255, 0, 85, 0.05) 0%, transparent 20%);
}

.container {
    width: 100%;
    max-width: 600px;
    padding: 2rem;
    perspective: 1000px;
}

.glass-panel {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: var(--glass-border);
    border-radius: 24px;
    padding: 40px;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    text-align: center;
    transition: border-color 0.1s ease, box-shadow 0.1s ease;
}

/* removed global fadeIn to keep panel fixed; animation played only on explicit classes if needed */

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #fff 0%, var(--accent-color) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 30px rgba(0, 242, 234, 0.2);
}

h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.hidden {
    display: none !important;
}

/* Controls & Inputs */
.btn {
    padding: 14px 32px;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    background: var(--accent-color);
    color: #000;
    transition: all 0.3s ease;
    box-shadow: 0 0 15px rgba(0, 242, 234, 0.2);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 25px rgba(0, 242, 234, 0.5);
    background: var(--accent-hover);
}

.btn-secondary {
    background: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    box-shadow: none;
}

.btn-secondary:hover {
    background: rgba(0, 242, 234, 0.1);
}

.settings-group {
    margin: 20px 0;
    text-align: left;
}

label {
    display: block;
    margin-bottom: 10px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 10px;
}

.radio-hidden {
    display: none;
}

.option-box {
    padding: 15px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    cursor: pointer;
    text-align: center;
    transition: all 0.2s;
    user-select: none;
}

.radio-hidden:checked+.option-box {
    background: rgba(0, 242, 234, 0.15);
    border-color: var(--accent-color);
    color: var(--accent-color);
    box-shadow: 0 0 10px rgba(0, 242, 234, 0.2);
}

.option-box:hover {
    background: rgba(255, 255, 255, 0.08);
}

/* Game Area */
#problem-display {
    font-size: 4.5rem;
    font-weight: 700;
    margin: 30px 0;
    text-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
    min-height: 120px;
    /* keep card height stable when problem text changes */
    display: flex;
    align-items: center;
    justify-content: center;
}

#answer-input {
    width: 100%;
    background: transparent;
    border: none;
    border-bottom: 2px solid var(--accent-color);
    color: #fff;
    font-size: 3rem;
    text-align: center;
    padding: 10px;
    outline: none;
    font-family: 'Outfit', sans-serif;
}

/* Animations included in class toggle */

.feedback-light {
    display: none;
}

.feedback-light.show-green {
    background: var(--success-color);
    box-shadow: 0 0 30px var(--success-color), 0 0 60px var(--success-color);
    animation: light-pulse-green 0.6s ease-out;
    opacity: 1;
}

.feedback-light.show-red {
    background: var(--danger-color);
    box-shadow: 0 0 30px var(--danger-color), 0 0 60px var(--danger-color);
    animation: light-pulse-red 0.6s ease-out;
    opacity: 1;
}

@keyframes light-pulse-green {
    0% {
        transform: scale(1);
        box-shadow: 0 0 30px var(--success-color), 0 0 60px var(--success-color);
    }

    50% {
        transform: scale(1.1);
        box-shadow: 0 0 40px var(--success-color), 0 0 80px var(--success-color);
    }

    100% {
        transform: scale(1);
        box-shadow: 0 0 30px var(--success-color), 0 0 60px var(--success-color);
    }
}

@keyframes light-pulse-red {
    0% {
        transform: scale(1);
        box-shadow: 0 0 30px var(--danger-color), 0 0 60px var(--danger-color);
    }

    50% {
        transform: scale(1.1);
        box-shadow: 0 0 40px var(--danger-color), 0 0 80px var(--danger-color);
    }

    100% {
        transform: scale(1);
        box-shadow: 0 0 30px var(--danger-color), 0 0 60px var(--danger-color);
    }
}

.glass-panel.correct-flash {
    border-color: var(--success-color);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37), 0 0 20px rgba(0, 255, 157, 0.3);
}

.glass-panel.wrong-flash {
    border-color: var(--danger-color);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37), 0 0 20px rgba(255, 0, 85, 0.3);
}

/* Stats */
.hud {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.hud-item strong {
    color: #fff;
    margin-left: 5px;
}

/* Progress Bar */
.timer-container {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    margin-top: 30px;
    overflow: hidden;
}

.timer-bar {
    height: 100%;
    background: var(--accent-color);
    width: 100%;
    transition: width 1s linear;
}

.timer-low {
    background: var(--danger-color);
    box-shadow: 0 0 10px var(--danger-color);
}

/* Results */
.stat-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 30px 0;
}

.stat-card {
    background: rgba(0, 0, 0, 0.2);
    padding: 15px;
    border-radius: 12px;
}

.stat-value {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    color: var(--accent-color);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Accessibility: respect reduce motion preferences */
@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
    }
}