:root {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --card-bg: #1e293b;
    --border-color: #334155;
    
    /* Status Colors */
    --color-1xx: #3b82f6;
    --color-2xx: #22c55e;
    --color-3xx: #eab308;
    --color-4xx: #f97316;
    --color-5xx: #ef4444;
    
    --primary: #6366f1;
    --primary-hover: #4f46e5;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Space Mono', 'Fira Code', monospace;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
}

#app {
    width: 100%;
    max-width: 600px;
    padding: 20px;
    position: relative;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

.screen {
    display: none;
    flex-direction: column;
    height: 100%;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.screen.active {
    display: flex;
}

h1 {
    font-size: 2rem;
    margin-bottom: 10px;
    text-shadow: 0 0 10px var(--primary);
}

p {
    margin-bottom: 30px;
    opacity: 0.8;
}

.modes {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
    max-width: 300px;
    margin-bottom: 20px;
}

.cmd-btn {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--text-color);
    padding: 12px 20px;
    font-size: 1rem;
    cursor: pointer;
    border-radius: 8px;
    transition: all 0.2s;
    outline: none;
}

.cmd-btn:hover {
    background: var(--primary);
    box-shadow: 0 0 15px var(--primary);
}

.cmd-btn[data-mode="1xx"] { border-color: var(--color-1xx); }
.cmd-btn[data-mode="1xx"]:hover { background: var(--color-1xx); box-shadow: 0 0 15px var(--color-1xx); }

.cmd-btn[data-mode="2xx"] { border-color: var(--color-2xx); }
.cmd-btn[data-mode="2xx"]:hover { background: var(--color-2xx); box-shadow: 0 0 15px var(--color-2xx); }

.cmd-btn[data-mode="3xx"] { border-color: var(--color-3xx); }
.cmd-btn[data-mode="3xx"]:hover { background: var(--color-3xx); box-shadow: 0 0 15px var(--color-3xx); }

.cmd-btn[data-mode="4xx"] { border-color: var(--color-4xx); }
.cmd-btn[data-mode="4xx"]:hover { background: var(--color-4xx); box-shadow: 0 0 15px var(--color-4xx); }

.cmd-btn[data-mode="5xx"] { border-color: var(--color-5xx); }
.cmd-btn[data-mode="5xx"]:hover { background: var(--color-5xx); box-shadow: 0 0 15px var(--color-5xx); }

.cmd-btn.secondary {
    border-color: var(--border-color);
    margin-top: 10px;
}
.cmd-btn.secondary:hover {
    background: var(--border-color);
    box-shadow: none;
}

/* GAME UI */
header {
    display: flex;
    justify-content: space-between;
    width: 100%;
    margin-bottom: 20px;
    background: var(--card-bg);
    padding: 15px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    margin-top: auto;
}

.stat-box {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-box .label {
    font-size: 0.8rem;
    opacity: 0.6;
    text-transform: uppercase;
}

.stat-box .value {
    font-size: 1.5rem;
    font-weight: bold;
}

.multiplier {
    color: var(--color-3xx);
    font-size: 0.8rem;
    font-weight: bold;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    margin-bottom: 30px;
    overflow: hidden;
}

#time-bar {
    height: 100%;
    background: var(--primary);
    width: 100%;
    transition: width 1s linear, background-color 0.3s;
}

.quiz-container {
    width: 100%;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.card {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: 16px;
    padding: 30px;
    width: 100%;
    text-align: center;
    font-size: 1.5rem;
    margin-bottom: 30px;
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    transition: border-color 0.3s;
}

.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    width: 100%;
}

.option-btn {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    color: var(--text-color);
    padding: 15px;
    font-size: 1.1rem;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 80px;
}

.option-btn:hover:not(:disabled) {
    background: var(--border-color);
    transform: translateY(-2px);
}

.option-btn:disabled {
    cursor: default;
    opacity: 0.8;
}

.option-btn.correct {
    background: var(--color-2xx);
    border-color: var(--color-2xx);
    color: #fff;
    box-shadow: 0 0 20px rgba(34, 197, 94, 0.4);
}

.option-btn.wrong {
    background: var(--color-5xx);
    border-color: var(--color-5xx);
    color: #fff;
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.4);
}

.explanation-panel {
    position: absolute;
    bottom: 20px;
    left: 20px;
    right: 20px;
    background: rgba(15, 23, 42, 0.95);
    border: 2px solid var(--primary);
    border-radius: 12px;
    padding: 20px;
    z-index: 10;
    text-align: left;
    backdrop-filter: blur(10px);
}

.explanation-panel.hidden {
    display: none;
}

#exp-status {
    font-size: 1.2rem;
    margin-bottom: 5px;
    color: var(--primary);
}

#exp-text {
    font-size: 0.9rem;
    margin-bottom: 15px;
}

/* GAME OVER */
.final-stats {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 30px;
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 300px;
}

.final-stats p {
    font-size: 1.2rem;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
}

.highlight {
    color: var(--color-3xx);
    font-weight: bold;
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    width: 100%;
    max-width: 300px;
}

input {
    flex: 1;
    background: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-color);
    padding: 10px;
    border-radius: 8px;
    outline: none;
}

input:focus {
    border-color: var(--primary);
}

/* MODAL */
.modal {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    padding: 30px;
    border-radius: 16px;
    width: 90%;
    max-width: 400px;
}

.tabs {
    display: flex;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
}

.tab {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-color);
    padding: 10px;
    cursor: pointer;
    font-size: 1rem;
    opacity: 0.5;
}

.tab.active {
    opacity: 1;
    border-bottom: 2px solid var(--primary);
    margin-bottom: -2px;
}

#scoreList {
    max-height: 250px;
    overflow-y: auto;
    margin-bottom: 20px;
    text-align: left;
}

.score-row {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px dashed var(--border-color);
}

/* Animations */
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.shake {
    animation: shake 0.2s ease-in-out 2;
}