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

html, body {
    height: 100%;
    margin: 0;
    padding: 0;
}

body {
    display: flex;
    flex-direction: column;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.container {
    margin: 20px auto;
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 20px;
    width: 100%;
    max-width: 1200px; /* 큰 화면에서는 여유 있게 */
    min-height: 700px;
}

.main-content {
    flex: 1;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
    overflow-y: auto;
}

.hidden {
    display: none !important;
}

/* 📱 모바일 최적화 */
@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr; /* 한 줄 */
        grid-template-rows: auto 1fr;
        width: 100%;
        max-width: 100%;
        min-height: auto; /* 고정 제거 */
        gap: 15px;
        padding: 10px;
    }

    .main-content {
        padding: 15px;
        border-radius: 12px;
    }
}