:root {
    --bg-color: #f0f2f5;
    --text-color: #333333;
    --container-bg: #ffffff;
    --primary: #0f3460;
    --accent: #e94560;
    --cup-width: 60px;
    --cup-height: 80px;
    --cup-gap: 20px;
    --border-color: rgba(0,0,0,0.1);
    --history-bg: rgba(0,0,0,0.03);
    --empty-cup-border: rgba(0,0,0,0.2);
    --modal-bg: rgba(255,255,255,0.95);
    --shadow-color: rgba(0,0,0,0.1);
    --board-shadow: 0 10px 40px rgba(0,0,0,0.1), inset 0 2px 5px rgba(0,0,0,0.02);
    --cup-shadow: inset -5px -5px 15px rgba(255,255,255,0.2), 0 5px 10px rgba(0,0,0,0.15);
    --instruction-color: #555;
    --timer-color: #333;
    --scroll-thumb: rgba(0,0,0,0.2);
    --slot-hover: rgba(0,0,0,0.03);
    --button-text-hover: white;
    --instructions-b: #111;
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --text-color: #eaeaea;
    --container-bg: #16213e;
    --border-color: rgba(255,255,255,0.1);
    --history-bg: rgba(255,255,255,0.05);
    --empty-cup-border: rgba(255,255,255,0.15);
    --modal-bg: rgba(0,0,0,0.85);
    --shadow-color: rgba(0,0,0,0.8);
    --board-shadow: 0 10px 40px rgba(0,0,0,0.6), inset 0 2px 5px rgba(255,255,255,0.05);
    --cup-shadow: inset -5px -5px 15px rgba(0,0,0,0.3), 0 5px 10px rgba(0,0,0,0.5);
    --instruction-color: #a0a0b0;
    --timer-color: var(--accent);
    --scroll-thumb: rgba(255,255,255,0.2);
    --slot-hover: rgba(255,255,255,0.05);
    --instructions-b: #fff;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
    margin: 0;
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s, color 0.3s;
}

h1 { margin-bottom: 5px; font-size: 24px; text-align: center; }

.instructions { 
    color: var(--instruction-color); 
    margin-bottom: 25px; 
    font-size: 14px; 
    text-align: center; 
    max-width: 450px; 
    line-height: 1.5;
    transition: color 0.3s;
}

.instructions b { color: var(--instructions-b); }

.game-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 320px;
}

/* History Stack */
.history-container {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 15px;
    opacity: 0.8;
    align-items: center;
    transition: all 0.3s;
    max-height: 337px;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--scroll-thumb) transparent;
}

.history-container::-webkit-scrollbar {
    width: 6px;
}
.history-container::-webkit-scrollbar-track {
    background: transparent;
}
.history-container::-webkit-scrollbar-thumb {
    background-color: var(--scroll-thumb);
    border-radius: 10px;
}

.history-row {
    display: flex;
    align-items: center;
    padding: 8px 12px;
    background: var(--history-bg);
    border-radius: 8px;
    width: 100%;
    box-sizing: border-box;
    box-shadow: 0 4px 6px var(--shadow-color);
    animation: slideDownFade 0.4s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
    overflow: hidden;
    flex-shrink: 0;
    transition: background 0.3s;
}

@keyframes slideDownFade {
    0% {
        opacity: 0;
        max-height: 0;
        padding-top: 0;
        padding-bottom: 0;
        margin-bottom: -8px; 
        transform: translateY(-10px) scale(0.95);
    }
    100% {
        opacity: 1;
        max-height: 80px;
        padding-top: 8px;
        padding-bottom: 8px;
        margin-bottom: 0;
        transform: translateY(0) scale(1);
    }
}

.history-slots {
    display: flex;
    gap: 15px; 
    padding-left: 5px;
}

.history-cup {
    width: 40px;
    height: 45px;
    border-radius: 6px 6px 8px 8px;
    box-shadow: inset -3px -3px 8px rgba(0,0,0,0.3);
    position: relative;
}

.history-cup::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 6px;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
}

.history-result {
    margin-left: auto;
    font-weight: bold;
    color: #4cd137;
    font-size: 18px;
    text-shadow: 0 1px 2px var(--shadow-color);
}

/* Interactive Board */
.board-container {
    position: relative;
    width: 320px; 
    height: 230px; 
    background: var(--container-bg);
    border-radius: 16px;
    box-shadow: var(--board-shadow);
    transition: background 0.3s, box-shadow 0.3s;
}

/* The physical slots where cups go */
.slot {
    position: absolute;
    width: var(--cup-width);
    height: var(--cup-height);
    border-radius: 10px 10px 15px 15px;
    border: 2px dashed var(--empty-cup-border);
    box-sizing: border-box;
    transition: background 0.2s, border-color 0.3s;
}

.slot:hover {
    background: var(--slot-hover);
}

.table-slot { top: 130px; cursor: pointer; }
.table-slot::after {
    content: attr(data-key);
    position: absolute;
    top: calc(100% + 8px); 
    left: 50%;
    transform: translateX(-50%);
    font-size: 14px;
    font-weight: 800;
    color: var(--instruction-color);
    pointer-events: none;
    font-family: monospace;
}
.pool-slot { top: 20px; border-color: transparent; }

.pos-0 { left: 10px; }
.pos-1 { left: 90px; }
.pos-2 { left: 170px; }
.pos-3 { left: 250px; }

/* The Animated Cups */
.cup {
    position: absolute;
    width: var(--cup-width);
    height: var(--cup-height);
    border-radius: 10px 10px 15px 15px;
    cursor: pointer;
    transition: all 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow: var(--cup-shadow);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    align-items: center;
    padding-bottom: 20px;
    box-sizing: border-box;
    z-index: 10;
}

.cup::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 12px;
    background: rgba(255,255,255,0.3);
    border-radius: 50%;
}

.cup.selected {
    transform: scale(1.1) translateY(-10px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.3), var(--cup-shadow);
    border: 2px solid white;
    z-index: 20;
}

.controls {
    margin-top: 25px;
    display: flex;
    gap: 15px;
    width: 100%;
}

button {
    flex-grow: 1;
    background-color: var(--accent);
    color: white; 
    border: none; 
    padding: 14px 20px; 
    border-radius: 10px; 
    font-size: 16px;
    font-weight: bold; 
    cursor: pointer; 
    transition: 0.2s;
    box-shadow: 0 4px 10px var(--shadow-color);
}

button:hover:not(:disabled) { 
    background-color: #f05a74; 
    transform: translateY(-2px);
    box-shadow: 0 6px 15px var(--shadow-color);
}

button:active:not(:disabled) {
    transform: translateY(0);
}

button:disabled { 
    background-color: #aaa; 
    color: #555;
    cursor: not-allowed; 
    box-shadow: none;
}

[data-theme="dark"] button:disabled {
    background-color: #333; 
    color: #777;
}