:root {
    --bg-color: #f0f4f8;
    --text-color: #102a43;
    --board-bg: #243b53;
    --board-shadow: rgba(0, 0, 0, 0.2);
    --cell-empty: #e2e8f0;
    --cell-empty-shadow: inset 0 3px 6px rgba(0,0,0,0.1);
    --player1-color: #e53e3e; /* Red */
    --player2-color: #ecc94b; /* Yellow */
    --player1-shadow: #c53030;
    --player2-shadow: #d69e2e;
    --hover-bg: rgba(255, 255, 255, 0.05);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.game-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 30px;
    width: 100%;
    max-width: 600px;
}

header {
    text-align: center;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    margin-bottom: 15px;
    color: var(--board-bg);
}

.turn-indicator {
    display: inline-block;
    font-size: 1.25rem;
    font-weight: 600;
    padding: 10px 24px;
    border-radius: 50px;
    background: white;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.turn-indicator.player1 {
    color: var(--player1-color);
    border: 2px solid var(--player1-color);
}

.turn-indicator.player2 {
    color: var(--player2-color);
    border: 2px solid var(--player2-color);
}

.board-container {
    background-color: var(--board-bg);
    padding: 15px;
    border-radius: 16px;
    box-shadow: 0 10px 25px var(--board-shadow), inset 0 2px 0 rgba(255,255,255,0.2);
    position: relative;
    overflow: hidden;
}

.board {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    grid-template-rows: repeat(6, 1fr);
    gap: 10px;
}

.column {
    display: flex;
    flex-direction: column;
    gap: 10px;
    cursor: pointer;
    position: relative;
    padding: 5px;
    border-radius: 40px;
    transition: background-color 0.2s ease;
}

.column:hover {
    background-color: var(--hover-bg);
}

.cell {
    width: 60px;
    height: 60px;
    background-color: var(--cell-empty);
    border-radius: 50%;
    box-shadow: var(--cell-empty-shadow);
    position: relative;
    overflow: hidden;
    z-index: 2;
}

/* Tokens */
.token {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    position: absolute;
    top: 0;
    left: 0;
    animation: dropIn 0.5s cubic-bezier(0.25, 1, 0.5, 1) forwards;
}

.token.player1 {
    background: radial-gradient(circle at 30% 30%, #fc8181, var(--player1-color));
    box-shadow: inset -3px -3px 8px var(--player1-shadow), 0 3px 6px rgba(0,0,0,0.3);
}

.token.player2 {
    background: radial-gradient(circle at 30% 30%, #f6e05e, var(--player2-color));
    box-shadow: inset -3px -3px 8px var(--player2-shadow), 0 3px 6px rgba(0,0,0,0.3);
}

@keyframes dropIn {
    0% {
        transform: translateY(-400px);
        opacity: 0;
    }
    60% {
        transform: translateY(20px);
        opacity: 1;
    }
    80% {
        transform: translateY(-10px);
    }
    100% {
        transform: translateY(0);
    }
}

/* Overlay */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(36, 59, 83, 0.85);
    display: flex;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(4px);
    z-index: 10;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.overlay-content {
    background: white;
    padding: 30px 40px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 15px 35px rgba(0,0,0,0.2);
    transform: translateY(0);
    transition: transform 0.3s ease;
}

.overlay.hidden .overlay-content {
    transform: translateY(20px);
}

#winnerMessage {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--board-bg);
}

.btn {
    background-color: var(--board-bg);
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: inherit;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(36, 59, 83, 0.3);
}

.btn:active {
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 600px) {
    .cell {
        width: 40px;
        height: 40px;
    }
    .board {
        gap: 6px;
    }
    .column {
        gap: 6px;
        padding: 3px;
    }
    h1 {
        font-size: 2rem;
    }
}