* {
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: #f0f0f0;
    margin: 0;
    padding: 20px;
    box-sizing: border-box;
}

h1 {
    color: #333;
    margin-bottom: 10px;
}

.back-to-hub {
    font-size: 0.8rem;
    color: #777;
    text-decoration: none;
}
.back-to-hub:hover {
    color: #1e88e5;
    text-decoration: underline;
}

/* Hide once installed as a home-screen app -- there's no "back" to a
   browsing session to offer, and it'd break out of the app shell. */
@media (display-mode: standalone), (display-mode: fullscreen), (display-mode: minimal-ui) {
    .back-to-hub { display: none; }
}

.game-info {
    display: flex;
    justify-content: space-between;
    width: 100%;
    max-width: 600px;
    margin-bottom: 20px;
}

.score, .timer {
    font-size: 1.2rem;
    font-weight: bold;
    padding: 10px 20px;
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.board-size {
    font-size: 1.2rem;
    font-weight: bold;
    padding: 10px 20px;
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    gap: 10px;
}

.board-size select {
    padding: 4px 8px;
    border-radius: 4px;
    border: 1px solid #ccc;
    font-size: 1rem;
    cursor: pointer;
}

.game-board {
    display: grid;
    gap: 4px;
    background-color: #ccc;
    padding: 10px;
    border-radius: 5px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 600px;
    aspect-ratio: 1 / 1;
}

.tile {
    background-color: #888;
    border-radius: 5px;
    cursor: pointer;
    transition: transform var(--flip-duration) ease;
    transform-style: preserve-3d;
    position: relative;
}

.tile:hover {
    transform: scale(0.95);
}

.tile.flipped {
    transform: rotateY(180deg);
}

.tile.matched {
    visibility: hidden;
}

.tile-front, .tile-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 5px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.tile-front {
    background-color: #888;
}

.tile-back {
    transform: rotateY(180deg);
}

.actions {
    margin-top: 20px;
}

button {
    padding: 10px 20px;
    font-size: 1rem;
    border: none;
    border-radius: 5px;
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    margin: 0 10px;
}

button:hover {
    background-color: #45a049;
}

/* Records panel */
.records {
    background-color: #fff;
    padding: 15px 20px;
    border-radius: 5px;
    margin-top: 20px;
    width: 100%;
    max-width: 600px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.records h3 {
    margin: 0 0 12px 0;
    color: #333;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.records-grid {
    display: grid;
    grid-template-columns: auto 1fr 1fr;
    gap: 6px 16px;
    font-size: 0.95rem;
}

.records-grid .col-header {
    font-weight: bold;
    color: #666;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding-bottom: 4px;
    border-bottom: 1px solid #eee;
}

.records-grid .size-label {
    font-weight: bold;
    color: #333;
}

.records-grid .record-val {
    color: #333;
}

.records-grid .record-val.no-record {
    color: #aaa;
    font-style: italic;
}

.records-grid .record-val.new-record {
    color: #4CAF50;
    font-weight: bold;
}

/* Game over overlay */
.game-over {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    color: white;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s ease;
}

.game-over.show {
    opacity: 1;
    pointer-events: all;
}

.game-over h2 {
    font-size: 3rem;
    margin-bottom: 20px;
}

.game-over p {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.game-over .new-record-banner {
    font-size: 1.2rem;
    color: #FFD700;
    margin-bottom: 20px;
    min-height: 1.5em;
    text-align: center;
}

/* Instructions */
.instructions {
    background-color: #fff;
    padding: 15px;
    border-radius: 5px;
    margin-top: 20px;
    width: 100%;
    max-width: 600px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    line-height: 1.5;
}

.instructions h3 {
    margin-top: 0;
    color: #333;
}

@media (max-width: 640px) {
    body {
        padding: 10px;
    }
    .game-board {
        gap: 2px;
        padding: 5px;
    }
    .score, .timer, .board-size {
        font-size: 0.9rem;
        padding: 6px 10px;
    }
    .board-size select {
        font-size: 0.9rem;
        padding: 2px 4px;
    }
    h1 {
        font-size: 1.5rem;
        margin-bottom: 10px;
    }
    .instructions p {
        font-size: 0.9rem;
    }
}

/* Speed control */
:root {
    --flip-duration: 0.3s;
}

.speed-control {
    display: flex;
    align-items: center;
    gap: 8px;
    width: 100%;
    max-width: 600px;
    margin-bottom: 12px;
}

.speed-label {
    font-size: 0.95rem;
    font-weight: bold;
    color: #555;
    margin-right: 4px;
}

.speed-btn {
    padding: 6px 16px;
    font-size: 0.9rem;
    background-color: #e0e0e0;
    color: #444;
    border: 2px solid transparent;
    border-radius: 20px;
    cursor: pointer;
    margin: 0;
    transition: all 0.15s ease;
}

.speed-btn:hover {
    background-color: #d0d0d0;
}

.speed-btn.active {
    background-color: #4CAF50;
    color: white;
    border-color: #388e3c;
}