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

html {
    width: 100%;
    height: 100%;
    overflow: hidden;
    overscroll-behavior: none;
}

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    width: 100%;
    height: 100%;
    min-height: 100%;
    color: #333;
    overflow: hidden;
    overscroll-behavior: none;
}

/* 画面管理 */
.screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: grid;
    place-items: center;
    transition: opacity 0.5s ease-in-out;
}

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

.screen-scale-screen {
    overflow: hidden;
    padding: 0;
}

.screen-scale-target {
    --screen-scale: 1;
    transform: scale(var(--screen-scale));
    transform-origin: center center;
    will-change: transform;
}