.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--card-bg);
    padding: var(--spacing-lg);
    border-radius: 0.75rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

main .container {
    margin-top: var(--spacing-md);
}

main .container h2 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    text-align: left;
}

form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

label {
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-color);
}

.required {
    color: var(--accent-color);
}

input,
textarea {
    padding: 0.875rem;
    border: 2px solid #ced4da;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-family: inherit;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: border-color 0.3s, box-shadow 0.3s, background-color 0.3s;
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.15);
}

textarea {
    resize: vertical;
    min-height: 120px;
}

input:required,
textarea:required {
    border-left: 4px solid var(--secondary-color);
}

input:optional,
textarea:optional {
    border-left: 4px solid #ced4da;
}

input:invalid:not(:placeholder-shown),
textarea:invalid:not(:placeholder-shown) {
    border-color: var(--accent-color);
    background-color: rgba(231, 76, 60, 0.05);
    border-left: 4px solid var(--accent-color);
}

input:valid:not(:placeholder-shown),
textarea:valid:not(:placeholder-shown) {
    border-color: #27ae60;
    border-left: 4px solid #27ae60;
    background-color: rgba(39, 174, 96, 0.05);
}

input[type="email"]:invalid:not(:placeholder-shown) {
    border-color: var(--accent-color);
    background-color: rgba(231, 76, 60, 0.05);
}

input[type="email"]:valid:not(:placeholder-shown) {
    border-color: #27ae60;
    background-color: rgba(39, 174, 96, 0.05);
}

input:invalid:not(:focus):not(:placeholder-shown) {
    animation: shake 0.3s;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

form button[type="submit"] {
    margin-top: var(--spacing-sm);
}

.char-counter {
    font-size: 0.875rem;
    color: #666;
    margin-top: 0.5rem;
    text-align: right;
    transition: color 0.3s;
}

.char-counter.warning {
    color: #f39c12;
    font-weight: 600;
}

.char-counter.error {
    color: var(--accent-color);
    font-weight: 600;
}

.error-message,
.info-message {
    padding: 0.875rem;
    border-radius: 0.5rem;
    font-size: 0.9rem;
    margin-top: var(--spacing-sm);
}

.error-message {
    color: #721c24;
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
}

.info-message {
    color: #004085;
    background-color: #d1ecf1;
    border: 1px solid #bee5eb;
}

.error-message:empty,
.info-message:empty {
    display: none;
}

.field-error {
    animation: shake 0.3s, flash 0.5s;
    border-color: var(--accent-color) !important;
    background-color: rgba(231, 76, 60, 0.1) !important;
}

@keyframes flash {
    0%, 100% { background-color: rgba(231, 76, 60, 0.1); }
    50% { background-color: rgba(231, 76, 60, 0.2); }
}

.fade-out {
    animation: fadeOut 2s forwards;
}

@keyframes fadeOut {
    0% { opacity: 1; }
    70% { opacity: 1; }
    100% { opacity: 0; }
}

main#main-content {
    max-width: 1000px;
    margin: var(--spacing-lg) auto;
    padding: var(--spacing-md);
}

@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
        margin: 0 var(--spacing-sm);
    }
    
    main#main-content {
        padding: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .container {
        padding: var(--spacing-sm);
        border-radius: 0.5rem;
    }
    
    input,
    textarea {
        padding: 0.75rem;
        font-size: 16px; 
    }
}