:root {
    --primary-color: #007bff;
    --error-color: #dc3545;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --border-color: #ced4da;
    --text-color: #333;
    --bg-color: #fff;
}


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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #f5f5f5;
    padding: 20px;
}


.container {
    max-width: 600px;
    margin: 0 auto;
    background-color: var(--bg-color);
    padding: 40px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    margin-bottom: 30px;
    text-align: center;
    color: var(--primary-color);
}


form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}


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

label {
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 14px;
}

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


input,
textarea {
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    font-size: 16px;
    font-family: inherit;
    transition: border-color 0.3s, box-shadow 0.3s, background-color 0.3s;
}


input:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

textarea {
    resize: vertical;
    min-height: 100px;
}


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


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


input:invalid:not(:placeholder-shown),
textarea:invalid:not(:placeholder-shown) {
    border-color: var(--error-color);
    background-color: #fff5f5;
    border-left: 4px solid var(--error-color);
}


input:valid:not(:placeholder-shown),
textarea:valid:not(:placeholder-shown) {
    border-color: var(--success-color);
    border-left: 4px solid var(--success-color);
    background-color: #f0fff4;
}


input:valid:not(:placeholder-shown)::after,
textarea:valid:not(:placeholder-shown)::after {
    content: '✓';
    color: var(--success-color);
}


input[type="email"]:invalid:not(:placeholder-shown) {
    border-color: var(--error-color);
    background-color: #fff5f5;
}

input[type="email"]:valid:not(:placeholder-shown) {
    border-color: var(--success-color);
    background-color: #f0fff4;
}


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); }
}


button {
    padding: 12px 24px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
    margin-top: 10px;
}

button:hover {
    background-color: #0056b3;
}

button:active {
    transform: translateY(1px);
}

button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}


button:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}


.error-message,
.info-message {
    padding: 12px;
    border-radius: 4px;
    font-size: 14px;
    min-height: 20px;
}

.error-message {
    color: var(--error-color);
    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;
}


input:focus-visible,
textarea:focus-visible,
button:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}


.form-group {
    min-height: fit-content;
}


input,
textarea {
    transition: all 0.2s ease-in-out;
}


.char-counter {
    font-size: 14px;
    color: #666;
    margin-top: 5px;
    text-align: right;
    transition: color 0.3s;
}

.char-counter.warning {
    color: var(--warning-color);
    font-weight: bold;
}

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


.field-error {
    animation: shake 0.3s, flash 0.5s;
    border-color: var(--error-color) !important;
    background-color: #fff5f5 !important;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    50% { transform: translateX(10px); }
    75% { transform: translateX(-10px); }
}

@keyframes flash {
    0%, 100% { background-color: #fff5f5; }
    50% { background-color: #ffcccc; }
}


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

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

.error-message:not(:empty),
.info-message:not(:empty) {
    display: block;
}

.form-nav {
    display: flex;
    justify-content: center;
    background-color: var(--primary-color);
    padding: 1rem;
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.form-nav ul {
    display: flex;
    gap: 1.5rem;
    list-style: none;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0;
    margin: 0;
}

.form-nav li {
    padding: 0;
}

.form-nav a {
    color: white;
    text-decoration: none;
    padding: 0.5em 1em;
    border-radius: 0.25rem;
    transition: all 0.3s ease;
    display: block;
}

.form-nav a:hover {
    background-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.form-nav a[aria-current="page"] {
    background-color: rgba(255, 255, 255, 0.3);
    font-weight: 600;
}

/* Responsive navigation */
@media (max-width: 768px) {
    .form-nav ul {
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
    }
    
    .form-nav a {
        padding: 0.75rem 2rem;
        width: 200px;
        text-align: center;
    }
}