:root{--primary-color: #4CAF50;--secondary-color: #388E3C;--text-color: #333;--background-color: #f4f7f6;--card-background: #fff;--border-color: #ddd;--shadow-light: 0 2px 5px rgba(0,0,0,.1);--shadow-hover: 0 4px 10px rgba(0,0,0,.2)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background-color:var(--background-color);color:var(--text-color);line-height:1.6}.app-container{max-width:900px;margin:0 auto;padding:20px}.app-header{background-color:var(--primary-color);color:#fff;padding:20px;text-align:center;border-radius:8px;margin-bottom:20px;box-shadow:var(--shadow-light)}.new-post-form-container{background-color:var(--card-background);padding:25px;border-radius:8px;box-shadow:var(--shadow-light);margin-bottom:20px}.new-post-form-container h2{margin-bottom:15px;color:var(--primary-color)}.new-post-form-container form div{margin-bottom:15px}.new-post-form-container label{display:block;font-weight:700;margin-bottom:5px}.new-post-form-container input,.new-post-form-container textarea{width:100%;padding:10px;border:1px solid var(--border-color);border-radius:5px;font-size:16px;transition:border-color .3s}.new-post-form-container input:focus,.new-post-form-container textarea:focus{outline:none;border-color:var(--primary-color)}.new-post-form-container textarea{resize:vertical;min-height:100px}.submit-btn{display:block;width:100%;padding:12px;background-color:var(--primary-color);color:#fff;border:none;border-radius:5px;font-size:18px;cursor:pointer;transition:background-color .3s ease,transform .2s ease}.submit-btn:hover{background-color:var(--secondary-color);transform:translateY(-2px)}.post-list-container{display:grid;gap:20px}.post-item{background-color:var(--card-background);padding:20px;border-radius:8px;box-shadow:var(--shadow-light);transition:box-shadow .3s ease,transform .3s ease}.post-item:hover{box-shadow:var(--shadow-hover);transform:translateY(-5px)}.post-item h3{color:var(--primary-color);margin-bottom:10px}