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

body {
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    background: #f0f0f0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft JhengHei', 'PingFang SC', sans-serif;
}

/* Intro Screen */
#introScreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    transition: opacity 0.5s ease-in-out;
}

#introScreen.hidden {
    display: none;
    opacity: 0;
    pointer-events: none;
}

.intro-container {
    background: white;
    border-radius: 20px;
    padding: 60px;
    max-width: 700px;
    width: 90%;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    text-align: center;
    animation: slideIn 0.6s ease-out;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.intro-company {
    display: block;
    max-width: 100%;
    height: auto;
    margin-bottom: 20px;
    max-height: 120px;
}

.intro-title {
    font-size: 35px;
    font-weight: bold;
    color: #333;
    margin-bottom: 30px;
    line-height: 1.2;
}

.intro-description {
    font-size: 16px;
    color: #666;
    line-height: 1.8;
    margin-bottom: 40px;
    text-align: justify;
}

.mode-section {
    margin-bottom: 40px;
}

.mode-label {
    font-size: 14px;
    color: #999;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 15px;
    display: block;
}

.mode-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.mode-btn {
    flex: 1;
    min-width: 150px;
    padding: 15px 30px;
    border: 2px solid #ddd;
    background: white;
    border-radius: 10px;
    font-size: 15px;
    font-weight: 600;
    color: #666;
    cursor: pointer;
    transition: all 0.3s ease;
}

.mode-btn:hover {
    border-color: #667eea;
    color: #667eea;
    transform: translateY(-2px);
}

.mode-btn.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-color: #667eea;
}

.start-button {
    padding: 16px 60px;
    font-size: 18px;
    font-weight: bold;
    color: white;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.4);
}

.start-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 35px rgba(102, 126, 234, 0.6);
}

.start-button:active {
    transform: translateY(-1px);
}

/* Game Container */
#gameContainer {
    width: 100%;
    height: 100vh;
    margin: 0;
    padding: 0;
    overflow: hidden;
    display: none;
}

#gameContainer.active {
    display: block;
}

#myCanvasDiv {
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#myCanvas {
    display: block;
    background: #fff;
}