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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: #f5f5f5;
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1 {
    color: #333;
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-align: center;
}

#formulario {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    flex-wrap: wrap;
}

#mensaje {
    flex: 1;
    min-width: 200px;
    padding: 0.875rem 1.25rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
}

#mensaje:focus {
    border-color: #0099ff;
    box-shadow: 0 0 0 3px rgba(0, 153, 255, 0.1);
}

#mensaje::placeholder {
    color: #999;
}

#submit {
    padding: 0.875rem 2rem;
    background: #0099ff;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

#submit:hover {
    background: #0088ee;
    box-shadow: 0 4px 15px rgba(0, 153, 255, 0.3);
}

#notas {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

#notas > div {
    background: white;
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: all 0.3s ease;
}

#notas > div:hover {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
}

#notas p {
    flex: 1;
    color: #333;
    font-size: 1rem;
    line-height: 1.5;
    word-break: break-word;
}

#notas button {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    color: white;
}

#notas button:first-of-type {
    background: #0099ff;
}

#notas button:first-of-type:hover {
    background: #0088ee;
}

#notas button:last-of-type {
    background: #ff4444;
}

#notas button:last-of-type:hover {
    background: #ee3333;
}

.alerta {
    width: 100%;
    padding: 1rem;
    margin-top: 1rem;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 500;
    text-align: center;
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.alerta.error {
    background: #ffebee;
    color: #c62828;
    border: 1px solid #ef5350;
}

.alerta.exito {
    background: #e8f5e9;
    color: #2e7d32;
    border: 1px solid #66bb6a;
}

@media (max-width: 600px) {
    body {
        padding: 1rem;
    }

    h1 {
        font-size: 1.5rem;
        margin-bottom: 1.5rem;
    }

    #formulario {
        padding: 1.5rem;
    }

    #notas > div {
        flex-direction: column;
        align-items: stretch;
    }

    #notas button {
        width: 100%;
    }
}

.notas-vacias {
    text-align: center;
}