html,body{height:100%;margin:0;display:flex;flex-direction:column}h2{text-align:left;color:#333}hr{border:0;height:1px;background-color:#325ca6;margin-bottom:20px}.alert{max-width:600px;margin:0 auto 20px;padding:12px 20px;font-size:1rem}@media (min-width: 768px){.alert{font-size:1.15rem}}@media (min-width: 1024px){.alert{font-size:1.25rem}}@media (min-width: 1366px){.alert{font-size:1.4rem}}.btn{font-size:1rem;padding:12px 25px;background-color:#007bff;border:none;color:#fff}@media (min-width: 768px){.btn{font-size:1.2rem}}@media (min-width: 1024px){.btn{font-size:1.4rem}}@media (min-width: 1366px){.btn{font-size:1.6rem}}.text-center{display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}.code-input{font-size:1.2rem;text-align:center;margin:0 5px;border:1px solid #ddd;border-radius:5px}@media (min-width: 768px){.code-input{width:50px;height:50px;font-size:2rem}}@media (max-width: 767px){.code-input{width:40px;height:40px;font-size:1.5rem}}@media (max-width: 400px){.code-input{width:30px;height:30px;font-size:1rem}}