Galería de Estilos de Formularios

<form class="form-glass">
    <h2>Crear Cuenta</h2>
    <p class="form-subtitle">Completa el formulario para registrarte</p>
    
    <div class="form-group">
        <input type="text" id="name" required>
        <label for="name">Nombre completo</label>
        <span class="input-line"></span>
        <span class="error-message">Por favor ingresa tu nombre</span>
    </div>

    <div class="form-group">
        <input type="email" id="email" required>
        <label for="email">Correo electrónico</label>
        <span class="input-line"></span>
        <span class="error-message">Ingresa un correo válido</span>
    </div>

    <div class="form-group">
        <input type="password" id="password" required>
        <label for="password">Contraseña</label>
        <span class="input-line"></span>
        <span class="error-message">La contraseña debe tener al menos 8 caracteres</span>
    </div>

    <div class="form-group">
        <select id="country" required>
            <option value="" disabled selected></option>
            <option value="es">España</option>
            <option value="mx">México</option>
            <option value="ar">Argentina</option>
            <option value="co">Colombia</option>
            <option value="cl">Chile</option>
        </select>
        <label for="country">País</label>
        <span class="input-line"></span>
    </div>

    <div class="form-group">
        <textarea id="message" required></textarea>
        <label for="message">Mensaje (opcional)</label>
        <span class="input-line"></span>
    </div>

    <div class="form-checkbox">
        <input type="checkbox" id="terms">
        <span class="checkbox-custom"></span>
        <label for="terms">Acepto los términos y condiciones</label>
    </div>

    <div class="form-submit">
        <button type="submit" class="submit-btn">Crear Cuenta</button>
    </div>
</form>

.form-glass {
    width: 100%;
    max-width: 450px;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 50px 40px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.form-glass h2 {
    font-size: 2rem;
    margin-bottom: 10px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.form-group {
    position: relative;
    margin-bottom: 35px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 15px 0;
    background: transparent;
    border: none;
    border-bottom: 2px solid rgba(255, 255, 255, 0.1);
    color: #fff;
    font-size: 16px;
    transition: all 0.3s ease;
    outline: none;
}

.form-group label {
    position: absolute;
    left: 0;
    top: 15px;
    color: rgba(255, 255, 255, 0.5);
    font-size: 16px;
    transition: all 0.3s ease;
    pointer-events: none;
}

.form-group input:focus,
.form-group input:valid,
.form-group textarea:focus,
.form-group textarea:valid,
.form-group select:focus,
.form-group select:valid {
    border-bottom-color: #667eea;
}

.form-group input:focus ~ label,
.form-group input:valid ~ label,
.form-group textarea:focus ~ label,
.form-group textarea:valid ~ label,
.form-group select:focus ~ label,
.form-group select:valid ~ label {
    top: -20px;
    font-size: 14px;
    color: #667eea;
}

.form-group .input-line {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #667eea, #764ba2);
    transition: width 0.3s ease;
}

.form-group input:focus ~ .input-line,
.form-group textarea:focus ~ .input-line,
.form-group select:focus ~ .input-line {
    width: 100%;
}

.form-checkbox {
    display: flex;
    align-items: center;
    margin-bottom: 30px;
    cursor: pointer;
}

.form-checkbox input[type="checkbox"] {
    width: 0;
    height: 0;
    opacity: 0;
    position: absolute;
}

.form-checkbox .checkbox-custom {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 4px;
    margin-right: 12px;
    position: relative;
    transition: all 0.3s ease;
}

.form-checkbox input[type="checkbox"]:checked ~ .checkbox-custom {
    background: linear-gradient(45deg, #667eea, #764ba2);
    border-color: #667eea;
}

.form-checkbox .checkbox-custom::after {
    content: '';
    position: absolute;
    top: 3px;
    left: 6px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.form-checkbox input[type="checkbox"]:checked ~ .checkbox-custom::after {
    opacity: 1;
}

.submit-btn {
    width: 100%;
    padding: 15px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    border: none;
    border-radius: 50px;
    color: white;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.submit-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, transparent, 
                rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.submit-btn:hover::before {
    left: 100%;
}