html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow-x: hidden;
    font-family: system-ui, -apple-system, sans-serif;
}

* {
    box-sizing: border-box;
}

.container {
    display: flex;
    flex-direction: column;
    min-height: 100dvh; /* รองรับมือถือ */
    width: 100%;
}

/* Header */
.header {
    background: #333;
    color: white;
    padding: 0px 12px;
    padding-top: calc(12px + env(safe-area-inset-top));
}

/* Content */
.content {
    flex: 1;
    background: #f0f0f0;
    padding: 10px;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    padding: 10px 16px;
    padding-bottom: calc(10px + env(safe-area-inset-bottom));
    text-align: center;
}

/* Tablet / จอใหญ่ขึ้น */
@media (min-width: 768px) {
    .content {
        padding: 24px;
    }
}