時間帯切替とゴールデンアワー付きのThree.js草原シーン

Build an interactive Three.js landscape of a wide green field seen from ground level, with thousands of animated grass blades swaying in the wind, distant hills and trees fading into haze, and a soft sky. Overlay an elegant serif headline reading a sea of green in the lower left, and a compact control panel in the corner with a time-of-day selector offering morning, afternoon and golden hour. Changing the time of day smoothly shifts sky color, fog, light direction and grass tint, from cool misty morning to warm amber light. Add gentle automatic camera movement and short camera cuts for a cinematic feel. Use fog for depth and keep the frame rate smooth. Deliver one self-contained HTML file. Done means the field looks lush and natural, the lighting transitions work without jumps, and the interface stays minimal and readable over the scene.