:root {
    --primary-glow: rgba(173, 8, 255, 0.8); --secondary-glow: rgba(28, 117, 255, 0.8); --text-primary: #f0f0f0; --text-secondary: #a9a9c9; --solid-bg: #191932; --glass-bg: rgba(20, 20, 50, 0.5); --glass-border: rgba(255, 255, 255, 0.15);
}
* { box-sizing: border-box; }
body, html { margin: 0; padding: 0; font-family: 'Noto Sans SC', sans-serif; color: var(--text-primary); overflow-x: hidden; background-color: #0a0a1f; }
body { background-repeat: no-repeat; background-position: center center; background-attachment: fixed; background-size: cover; }
.container { display: flex; justify-content: center; align-items: center; min-height: 100vh; padding: 20px; }
.content-wrapper { width: 100%; max-width: 500px; border-radius: 20px; padding: 30px; box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37); text-align: center; animation: fade-in 1s ease-out; background-color: var(--solid-bg); border: 1px solid var(--glass-border); }
@supports (backdrop-filter: blur(15px)) or (-webkit-backdrop-filter: blur(15px)) { .content-wrapper { background-color: var(--glass-bg); backdrop-filter: blur(15px); -webkit-backdrop-filter: blur(15px); } }
@keyframes fade-in { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
section { margin-bottom: 40px; }
.hero-section .title-image-placeholder { width: 100%; max-width: 300px; height: auto; aspect-ratio: 16 / 9; margin: 0 auto 15px; background-repeat: no-repeat; background-position: center center; background-size: contain; }
.hero-section h1 { font-size: 24px; font-weight: 700; margin: 0 0 10px; text-shadow: 0 0 10px var(--primary-glow); }
.hero-section .subtitle { font-size: 16px; color: var(--text-secondary); margin: 0; }
.features-section { display: flex; justify-content: space-around; gap: 15px; }
.feature-card { flex: 1; min-width: 80px; opacity: 0; transform: translateY(20px); animation: fade-in 1s ease-out forwards; }
.feature-card:nth-child(1) { animation-delay: 0.2s; } .feature-card:nth-child(2) { animation-delay: 0.4s; } .feature-card:nth-child(3) { animation-delay: 0.6s; }
.feature-card .icon { font-size: 32px; } .feature-card h3 { font-size: 14px; margin: 10px 0 5px; font-weight: 500; } .feature-card p { font-size: 12px; color: var(--text-secondary); margin: 0; }
.cta-section h2 { font-size: 18px; margin-bottom: 20px; color: var(--text-secondary); font-weight: 400; }
.level-selector { display: flex; justify-content: center; background-color: rgba(0,0,0,0.2); border-radius: 50px; padding: 5px; margin-bottom: 25px; }
.level-btn { flex: 1; padding: 10px; border: none; background: transparent; color: var(--text-secondary); font-size: 16px; font-weight: 500; border-radius: 50px; cursor: pointer; transition: all 0.3s ease; }
.level-btn.active { background-color: var(--solid-bg); color: var(--text-primary); box-shadow: 0 2px 10px rgba(0,0,0,0.3); }
.grade-group-container { position: relative; }
.grade-group { display: none; flex-direction: column; gap: 15px; animation: fade-in-group 0.5s ease; }
.grade-group.active { display: flex; }
@keyframes fade-in-group { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.choice-btn { padding: 15px; font-size: 18px; font-weight: 700; color: white; background-image: linear-gradient(90deg, var(--primary-glow), var(--secondary-glow)); background-size: 200% 100%; border: none; border-radius: 50px; cursor: pointer; transition: all 0.4s ease; box-shadow: 0 4px 15px rgba(0,0,0,0.3); }
.choice-btn:hover { background-position: 100% 0; transform: translateY(-3px); box-shadow: 0 8px 20px rgba(0,0,0,0.5); }
.modal-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.7); display: flex; justify-content: center; align-items: center; opacity: 0; visibility: hidden; transition: opacity 0.3s ease, visibility 0.3s ease; z-index: 1000; }
.modal-overlay.visible { opacity: 1; visibility: visible; }
.modal-content { background: white; color: #333; padding: 30px; border-radius: 15px; text-align: center; width: 90%; max-width: 350px; transform: scale(0.9); transition: transform 0.3s ease; }
.modal-overlay.visible .modal-content { transform: scale(1); }
.modal-text { font-size: 16px; margin-top: 0; }
#qr-image { width: 100%; max-width: 250px; margin: 15px auto; display: block; }
.close-btn { margin-top: 10px; padding: 10px 30px; background: #f0f0f0; color: #333; border: 1px solid #ccc; border-radius: 50px; cursor: pointer; font-size: 16px; transition: background-color 0.2s; }
.close-btn:hover { background-color: #e0e0e0; }