.gtp-container {
    max-width: 480px;
    margin: 20px auto;
    padding: 24px;
    background: #ffffff;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: #1e293b;
    box-sizing: border-box;
}

.gtp-container * {
    box-sizing: border-box;
}

.gtp-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.gtp-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--gtp-primary, #2563eb);
}

.gtp-stats {
    font-size: 0.95rem;
    color: #64748b;
    display: flex;
    gap: 12px;
}

.gtp-stat-item strong {
    color: #0f172a;
}

.gtp-board-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 1 / 1;
    background: #f8fafc;
    border-radius: 12px;
    overflow: hidden;
    touch-action: none;
    border: 2px solid #e2e8f0;
}

#gtp-canvas {
    width: 100%;
    height: 100%;
    display: block;
    cursor: pointer;
}

.gtp-controls {
    display: flex;
    gap: 12px;
    margin-top: 20px;
}

.gtp-btn {
    flex: 1;
    padding: 12px 18px;
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.gtp-btn-primary {
    background: var(--gtp-primary, #2563eb);
    color: #ffffff;
}

.gtp-btn-primary:hover {
    filter: brightness(0.9);
}

.gtp-btn-secondary {
    background: #f1f5f9;
    color: #475569;
}

.gtp-btn-secondary:hover {
    background: #e2e8f0;
}

.gtp-overlay {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.75);
    display: flex;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(4px);
    animation: gtpFadeIn 0.3s ease;
}

.gtp-overlay.gtp-hidden {
    display: none;
}

.gtp-modal {
    background: #ffffff;
    padding: 28px;
    border-radius: 16px;
    text-align: center;
    max-width: 80%;
    box-shadow: 0 20px 25px -5px rgba(0,0,0,0.2);
}

.gtp-modal h2 {
    margin: 0 0 10px 0;
    color: #0f172a;
}

.gtp-modal p {
    margin: 0 0 16px 0;
    color: #64748b;
}

@keyframes gtpFadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}