.game-container {
    position: relative;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    background: linear-gradient(135deg, #8b0000 0%, #4a0404 100%);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.5);
    border: 1px solid rgba(255, 215, 0, 0.3);
}

#gameCanvas {
    width: 100%;
    height: 400px;
    background: linear-gradient(180deg, 
        rgba(74, 4, 4, 0.9) 0%,
        rgba(139, 0, 0, 0.8) 50%,
        rgba(74, 4, 4, 0.9) 100%
    );
}

.game-ui {
    padding: 1rem;
    background-color: rgba(0, 0, 0, 0.4);
    border-top: 1px solid rgba(255, 215, 0, 0.2);
}

@media (max-width: 576px) {
    .game-ui {
        padding: 0.75rem;
    }

    #gameCanvas {
        height: 300px;  /* モバイルでは少し小さく */
    }
}

.score-display {
    margin: 1rem 0;
    font-size: 1.2rem;
    color: #ffd700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: space-around;
    padding: 0.5rem;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    border: 1px solid rgba(255, 215, 0, 0.2);
}

@media (max-width: 576px) {
    .score-display {
        font-size: 1rem;
        margin: 0.75rem 0;
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
    }
}

#inputField {
    background-color: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 215, 0, 0.3);
    color: #fff;
    font-size: 1.2rem;
    padding: 0.8rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    width: 100%;
}

@media (max-width: 576px) {
    #inputField {
        font-size: 1rem;
        padding: 0.6rem;
    }
}

#inputField:focus {
    background-color: rgba(255, 255, 255, 0.15);
    border-color: #ffd700;
    box-shadow: 0 0 10px rgba(255, 215, 0, 0.3);
}

.btn {
    transition: all 0.3s ease;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
    font-weight: bold;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

@media (max-width: 576px) {
    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }

    .btn-sm {
        padding: 0.25rem 0.5rem;
        font-size: 0.8rem;
    }
}

.modal-content {
    background: linear-gradient(135deg, #8b0000 0%, #4a0404 100%);
    border: 1px solid rgba(255, 215, 0, 0.3);
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

.modal-header {
    border-bottom: 1px solid rgba(255, 215, 0, 0.2);
}

.modal-footer {
    border-top: 1px solid rgba(255, 215, 0, 0.2);
}

.collapsible-header {
    cursor: pointer;
    user-select: none;
    position: relative;
    padding: 0.5rem 1rem;
    margin: -0.5rem -1rem 1rem -1rem;
    border-radius: 8px;
    background: rgba(139, 0, 0, 0.4);
    border: 1px solid rgba(255, 215, 0, 0.2);
    transition: background-color 0.3s ease;
}

.collapsible-header:hover {
    background: rgba(139, 0, 0, 0.6);
}

.collapsible-header small {
    float: right;
    transition: transform 0.3s ease;
}

.collapsible-header[aria-expanded="true"] small i {
    transform: rotate(180deg);
}

#highScores {
    margin-top: 2rem;
    background: linear-gradient(135deg, rgba(139, 0, 0, 0.4) 0%, rgba(74, 4, 4, 0.4) 100%);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 215, 0, 0.2);
}

@media (max-width: 576px) {
    #highScores {
        padding: 1rem;
        margin-top: 1.5rem;
    }
}

#highScoresTitle {
    color: #ffd700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

@media (max-width: 576px) {
    #highScoresTitle {
        font-size: 1.4rem;
        margin-bottom: 1rem;
    }
}

.table {
    color: #fff;
    margin-top: 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid rgba(255, 215, 0, 0.2);
}

.table thead th {
    background-color: rgba(139, 0, 0, 0.8);
    border-color: rgba(255, 215, 0, 0.2);
    padding: 1rem;
    font-size: 1.1rem;
    color: #ffd700;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
    font-weight: bold;
}

@media (max-width: 576px) {
    .table thead th {
        padding: 0.75rem;
        font-size: 0.9rem;
    }

    .table tbody td {
        padding: 0.5rem;
        font-size: 0.85rem;
    }
}

.table tbody td {
    border-color: rgba(255, 215, 0, 0.1);
    padding: 0.8rem;
    vertical-align: middle;
    background-color: rgba(255, 255, 255, 0.02);
}

.table tbody tr:nth-child(1) {
    background-color: rgba(255, 215, 0, 0.1);
    font-weight: bold;
}

.table tbody tr:nth-child(2) {
    background-color: rgba(255, 255, 255, 0.07);
}

.table tbody tr:nth-child(3) {
    background-color: rgba(139, 69, 19, 0.15);
}

.table tbody tr:hover {
    background-color: rgba(255, 215, 0, 0.15);
    transition: background-color 0.3s ease;
}

body {
    background: linear-gradient(135deg, #4a0404 0%, #8b0000 100%);
    min-height: 100vh;
    padding: 2rem 0;
    display: flex;
    flex-direction: column;
}

@media (max-width: 576px) {
    body {
        padding: 1rem 0;
    }
}

#startButton {
    width: 100%;
    padding: 0.8rem;
    font-size: 1.2rem;
    margin-top: 1rem;
    background: linear-gradient(45deg, #ffd700 0%, #ffb700 100%);
    border: none;
    color: #4a0404;
    text-transform: uppercase;
    letter-spacing: 1px;
}

@media (max-width: 576px) {
    #startButton {
        padding: 0.6rem;
        font-size: 1rem;
        margin-top: 0.75rem;
    }
}

#startButton:hover {
    background: linear-gradient(45deg, #ffb700 0%, #ffd700 100%);
}

.footer {
    padding: 1.5rem 0;
    background: linear-gradient(135deg, rgba(139, 0, 0, 0.4) 0%, rgba(74, 4, 4, 0.4) 100%);
    border-top: 1px solid rgba(255, 215, 0, 0.2);
    color: #fff;
    margin-top: auto;
}

@media (max-width: 576px) {
    .footer {
        padding: 1rem 0;
    }
}

.social-link {
    color: #ffd700;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    text-decoration: none;
}

.social-link:hover {
    color: #fff;
    transform: translateY(-2px);
}

@media (max-width: 576px) {
    .social-link {
        font-size: 1rem;
    }
}

/* About page styles */
.about-container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background: linear-gradient(135deg, rgba(139, 0, 0, 0.4) 0%, rgba(74, 4, 4, 0.4) 100%);
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.5);
    border: 1px solid rgba(255, 215, 0, 0.3);
}

.about-section {
    margin-bottom: 2.5rem;
}

.about-section h2 {
    color: #ffd700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    margin-bottom: 1rem;
    font-size: 1.6rem;
}

.about-section p, .about-section li {
    color: #fff;
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.about-section ul, .about-section ol {
    padding-left: 1.5rem;
}

@media (max-width: 576px) {
    .about-container {
        margin: 1rem auto;
        padding: 1.5rem;
    }

    .about-section {
        margin-bottom: 2rem;
    }

    .about-section h2 {
        font-size: 1.4rem;
    }
}

/* Footer link styles */
.footer-links {
    margin-bottom: 1rem;
}

.footer-link {
    color: #ffd700;
    text-decoration: none;
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

.footer-link:hover {
    color: #fff;
    text-decoration: underline;
}

@media (max-width: 576px) {
    .footer-link {
        font-size: 1rem;
    }
}