diff --git a/Proyecto_Final_MemberFlow_v1.pdf b/Proyecto_Final_MemberFlow_v1.pdf
new file mode 100644
index 0000000..6e45cbf
Binary files /dev/null and b/Proyecto_Final_MemberFlow_v1.pdf differ
diff --git a/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar b/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar
index c9650ee..dfe6bb1 100644
Binary files a/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar and b/memberflow-api/libs/memberflow-data-1.0-SNAPSHOT.jar differ
diff --git a/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java b/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
index a53b52f..ff95ced 100644
--- a/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
+++ b/memberflow-api/src/main/java/com/denniseckerskorn/controllers/finance_management/PaymentController.java
@@ -34,8 +34,15 @@ public class PaymentController {
             throws DuplicateEntityException, EntityNotFoundException {
 
         Invoice invoice = paymentService.getInvoiceById(dto.getInvoiceId());
+        if (invoice == null) {
+            throw new EntityNotFoundException("Invoice not found with ID: " + dto.getInvoiceId());
+        }
+
         Payment saved = paymentService.save(dto.toEntityWithInvoice(invoice));
 
+        if (saved == null) {
+            throw new DuplicateEntityException("Payment already exists for invoice ID: " + dto.getInvoiceId());
+        }
         return new ResponseEntity<>(new PaymentDTO(saved), HttpStatus.CREATED);
     }
 
@@ -46,8 +53,15 @@ public class PaymentController {
             throws EntityNotFoundException, InvalidDataException {
 
         Invoice invoice = paymentService.getInvoiceById(dto.getInvoiceId());
+        if (invoice == null) {
+            throw new EntityNotFoundException("Invoice not found with ID: " + dto.getInvoiceId());
+        }
         Payment updated = paymentService.update(dto.toEntityWithInvoice(invoice));
 
+        if (updated == null) {
+            throw new InvalidDataException("Payment update failed for invoice ID: " + dto.getInvoiceId());
+        }
+        
         return new ResponseEntity<>(new PaymentDTO(updated), HttpStatus.OK);
     }
 
diff --git a/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java b/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
index 4fb78fe..83b99ca 100644
--- a/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
+++ b/memberflow-data/src/main/java/com/denniseckerskorn/services/finance_services/PaymentService.java
@@ -50,7 +50,7 @@ public class PaymentService extends AbstractService<Payment, Integer> {
 
         Payment savedPayment = super.save(payment);
 
-        invoice.setPayment(savedPayment);
+        //invoice.setPayment(savedPayment);
         invoice.setStatus(StatusValues.PAID);
         invoiceService.update(invoice);
 
@@ -58,14 +58,28 @@ public class PaymentService extends AbstractService<Payment, Integer> {
     }
 
 
-
     @Override
     @Transactional
-    public Payment update(Payment entity) throws EntityNotFoundException, InvalidDataException {
-        logger.info("Updating payment: {}", entity);
-        validate(entity);
-        updateInvoiceStatus(entity);
-        return super.update(entity);
+    public Payment update(Payment payment) throws EntityNotFoundException, InvalidDataException {
+        logger.info("Updating payment: {}", payment);
+        validate(payment);
+
+        Payment existingPayment = findById(payment.getId());
+
+        if (existingPayment == null) {
+            throw new EntityNotFoundException("Payment not found");
+        }
+
+        Invoice invoice = payment.getInvoice();
+
+        if (invoice == null || invoiceService.findById(invoice.getId()) == null) {
+            throw new EntityNotFoundException("Invoice not found for the payment");
+        }
+
+        invoice.setStatus(StatusValues.PAID);
+        invoiceService.update(invoice);
+
+        return super.update(payment);
     }
 
     @Override
@@ -102,18 +116,17 @@ public class PaymentService extends AbstractService<Payment, Integer> {
         }
     }
 
-    @Transactional
-    private void updateInvoiceStatus(Payment payment) {
-        Invoice invoice = payment.getInvoice();
-        invoice.setStatus(StatusValues.PAID);
-        invoiceService.update(invoice);
-    }
-
     @Transactional
     public void removePayment(Integer paymentId) {
         Payment payment = findById(paymentId);
+        if (payment == null) {
+            throw new EntityNotFoundException("The payment doesn't exist.");
+        }
+
         Invoice invoice = payment.getInvoice();
+
         super.deleteById(paymentId);
+
         invoice.setStatus(StatusValues.NOT_PAID);
         invoiceService.update(invoice);
     }
diff --git a/memberflow-frontend.zip b/memberflow-frontend.zip
deleted file mode 100644
index 0a01b46..0000000
Binary files a/memberflow-frontend.zip and /dev/null differ
diff --git a/memberflow-frontend/src/components/forms/IVATypeManager.jsx b/memberflow-frontend/src/components/forms/IVATypeManager.jsx
index fd06df9..6067bcc 100644
--- a/memberflow-frontend/src/components/forms/IVATypeManager.jsx
+++ b/memberflow-frontend/src/components/forms/IVATypeManager.jsx
@@ -1,35 +1,39 @@
 import React, { useEffect, useState } from "react";
 import api from "../../api/axiosConfig";
-
+import ErrorMessage from "../common/ErrorMessage";
+import "../styles/ContentArea.css";
 
 const IVATypeManager = () => {
   const [ivaTypes, setIvaTypes] = useState([]);
   const [newIva, setNewIva] = useState({ percentage: "", description: "" });
-  const [error, setError] = useState("");
+  const [errorMsg, setErrorMsg] = useState("");
+  const [successMsg, setSuccessMsg] = useState("");
+
+  useEffect(() => {
+    fetchIvaTypes();
+  }, []);
 
   const fetchIvaTypes = async () => {
     try {
       const res = await api.get("/iva-types/getAll");
       setIvaTypes(res.data);
+      setErrorMsg("");
     } catch (err) {
       console.error(err);
-      setError("Error al obtener los tipos de IVA.");
+      setErrorMsg("❌ Error al obtener los tipos de IVA.");
     }
   };
 
-  useEffect(() => {
-    fetchIvaTypes();
-  }, []);
-
   const handleChange = (e) => {
     const { name, value } = e.target;
     setNewIva((prev) => ({ ...prev, [name]: value }));
   };
 
   const handleAddIva = async () => {
-    setError("");
+    setErrorMsg("");
+    setSuccessMsg("");
     if (!newIva.percentage || isNaN(newIva.percentage)) {
-      setError("Introduce un porcentaje válido.");
+      setErrorMsg("❌ Introduce un porcentaje válido.");
       return;
     }
 
@@ -41,10 +45,11 @@ const IVATypeManager = () => {
 
       await api.post("/iva-types/create", payload);
       setNewIva({ percentage: "", description: "" });
+      setSuccessMsg("✅ Tipo de IVA añadido correctamente.");
       fetchIvaTypes();
     } catch (err) {
       console.error(err);
-      setError("No se pudo crear el tipo de IVA.");
+      setErrorMsg("❌ No se pudo crear el tipo de IVA.");
     }
   };
 
@@ -52,66 +57,70 @@ const IVATypeManager = () => {
     if (!window.confirm("¿Seguro que deseas eliminar este tipo de IVA?")) return;
     try {
       await api.delete(`/iva-types/deleteById/${id}`);
+      setSuccessMsg("✅ Tipo de IVA eliminado correctamente.");
       fetchIvaTypes();
     } catch (err) {
       console.error(err);
-      setError("No se pudo eliminar el tipo de IVA.");
+      setErrorMsg("❌ No se pudo eliminar el tipo de IVA.");
     }
   };
 
   return (
-    <div className="content-area">
+    <div className="card">
       <h2>Gestión de Tipos de IVA</h2>
 
-      {error && <p style={{ color: "red" }}>{error}</p>}
+      <ErrorMessage message={errorMsg} type="error" />
+      <ErrorMessage message={successMsg} type="success" />
 
-      <div className="form-section">
-        <label>Porcentaje:</label>
+      <div className="form-inline" style={{ marginBottom: "1.5rem" }}>
         <input
           type="number"
           name="percentage"
+          placeholder="Porcentaje (%)"
           value={newIva.percentage}
           onChange={handleChange}
           step="0.01"
+          className="form-input"
         />
-
-        <label>Descripción:</label>
         <input
           type="text"
           name="description"
+          placeholder="Descripción"
           value={newIva.description}
           onChange={handleChange}
+          className="form-input"
         />
-
         <button className="btn btn-primary" onClick={handleAddIva}>
           + Añadir IVA
         </button>
       </div>
 
-      <table className="table" style={{ marginTop: "2rem" }}>
-        <thead>
-          <tr>
-            <th>ID</th>
-            <th>Porcentaje</th>
-            <th>Descripción</th>
-            <th>Acciones</th>
-          </tr>
-        </thead>
-        <tbody>
-          {ivaTypes.map((iva) => (
-            <tr key={iva.id}>
-              <td>{iva.id}</td>
-              <td>{iva.percentage}%</td>
-              <td>{iva.description}</td>
-              <td>
-                <button className="btn btn-danger btn-sm" onClick={() => handleDelete(iva.id)}>
-                  🗑️ Eliminar
-                </button>
-              </td>
+      <div className="table-wrapper">
+        <table className="styled-table">
+          <thead>
+            <tr>
+              <th>ID</th>
+              <th>Porcentaje</th>
+              <th>Descripción</th>
+              <th>Acciones</th>
             </tr>
-          ))}
-        </tbody>
-      </table>
+          </thead>
+          <tbody>
+            {ivaTypes.map((iva) => (
+              <tr key={iva.id}>
+                <td>{iva.id}</td>
+                <td>{iva.percentage}%</td>
+                <td>{iva.description}</td>
+                <td>
+                  <button className="delete-btn" onClick={() => handleDelete(iva.id)}>
+                    🗑️
+                  </button>
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+      </div>
     </div>
   );
 };
diff --git a/memberflow-frontend/src/components/forms/InvoiceForm.jsx b/memberflow-frontend/src/components/forms/InvoiceForm.jsx
index 9f47838..ad27428 100644
--- a/memberflow-frontend/src/components/forms/InvoiceForm.jsx
+++ b/memberflow-frontend/src/components/forms/InvoiceForm.jsx
@@ -2,6 +2,7 @@ import React, { useEffect, useState } from "react";
 import InvoiceLineItem from "./InvoiceLineItem";
 import ErrorMessage from "../common/ErrorMessage";
 import api from "../../api/axiosConfig";
+import "../styles/ContentArea.css";
 
 const InvoiceForm = () => {
   const [students, setStudents] = useState([]);
@@ -17,9 +18,7 @@ const InvoiceForm = () => {
     api.get("/products-services/getAll").then((res) => setProducts(res.data));
   }, []);
 
-  const addLine = () => {
-    setLines([...lines, { productServiceId: "", quantity: 1 }]);
-  };
+  const addLine = () => setLines([...lines, { productServiceId: "", quantity: 1 }]);
 
   const updateLine = (index, updatedLine) => {
     const newLines = [...lines];
@@ -31,27 +30,21 @@ const InvoiceForm = () => {
     setLines(lines.filter((_, i) => i !== index));
   };
 
-  const calculateSubtotal = () => {
-    return lines.reduce((acc, line) => {
+  const calculateSubtotal = () =>
+    lines.reduce((acc, line) => {
       const product = products.find((p) => p.id === parseInt(line.productServiceId));
-      if (!product) return acc;
-      return acc + product.price * (parseInt(line.quantity) || 1);
+      return product ? acc + product.price * (parseInt(line.quantity) || 1) : acc;
     }, 0);
-  };
 
-  const calculateIVA = () => {
-    return lines.reduce((acc, line) => {
+  const calculateIVA = () =>
+    lines.reduce((acc, line) => {
       const product = products.find((p) => p.id === parseInt(line.productServiceId));
       if (!product || !product.ivaType) return acc;
       const quantity = parseInt(line.quantity) || 1;
-      const iva = product.ivaType.percentage || 0;
-      return acc + (product.price * quantity * (iva / 100));
+      return acc + (product.price * quantity * (product.ivaType.percentage / 100));
     }, 0);
-  };
 
-  const calculateTotal = () => {
-    return calculateSubtotal() + calculateIVA();
-  };
+  const calculateTotal = () => calculateSubtotal() + calculateIVA();
 
   const createInvoice = async () => {
     setError("");
@@ -84,7 +77,6 @@ const InvoiceForm = () => {
       setCreatedInvoice(res.data);
       alert("✅ Factura creada correctamente.");
     } catch (err) {
-      console.error(err);
       setError("❌ Error al crear la factura: " + (err.response?.data?.message || err.message));
     }
   };
@@ -102,7 +94,6 @@ const InvoiceForm = () => {
       document.body.appendChild(link);
       link.click();
     } catch (err) {
-      console.error(err);
       setError("❌ Error al descargar el PDF.");
     }
   };
@@ -112,32 +103,30 @@ const InvoiceForm = () => {
       <div className="card">
         <h2>Crear Factura</h2>
 
-        <label>Seleccionar estudiante:</label>
-        <select
-          className="form-select"
-          value={userId}
-          onChange={(e) => setUserId(e.target.value)}
-        >
-          <option value="">-- Selecciona un estudiante --</option>
-          {students.map((s) =>
-            s.user ? (
-              <option key={s.id} value={s.user.id}>
-                {s.user.name} {s.user.lastName} ({s.user.email})
-              </option>
-            ) : null
-          )}
-        </select>
+        <div className="form-column">
+          <label>Estudiante</label>
+          <select className="form-select" value={userId} onChange={(e) => setUserId(e.target.value)} required>
+            <option value="">-- Selecciona un estudiante --</option>
+            {students.map((s) =>
+              s.user ? (
+                <option key={s.id} value={s.user.id}>
+                  {s.user.name} {s.user.lastName} ({s.user.email})
+                </option>
+              ) : null
+            )}
+          </select>
 
-        <label>Fecha de emisión:</label>
-        <input
-          className="form-input"
-          type="datetime-local"
-          value={date}
-          onChange={(e) => setDate(e.target.value)}
-        />
+          <label>Fecha de emisión</label>
+          <input
+            className="form-input"
+            type="datetime-local"
+            value={date}
+            onChange={(e) => setDate(e.target.value)}
+            required
+          />
+        </div>
 
         <h3>Productos / Servicios</h3>
-
         {lines.map((line, i) => (
           <InvoiceLineItem
             key={i}
@@ -149,34 +138,33 @@ const InvoiceForm = () => {
           />
         ))}
 
-        <div style={{ marginTop: "1rem" }}>
-          <h4>Subtotal: <strong>{calculateSubtotal().toFixed(2)} €</strong></h4>
-          <h4>IVA: <strong>{calculateIVA().toFixed(2)} €</strong></h4>
-          <h4>Total estimado con IVA: <strong>{calculateTotal().toFixed(2)} €</strong></h4>
+        <div className="invoice-summary">
+          <div>
+            <h4>Subtotal:</h4>
+            <p><strong>{calculateSubtotal().toFixed(2)} €</strong></p>
+          </div>
+          <div>
+            <h4>IVA:</h4>
+            <p><strong>{calculateIVA().toFixed(2)} €</strong></p>
+          </div>
+          <div>
+            <h4>Total con IVA:</h4>
+            <p><strong>{calculateTotal().toFixed(2)} €</strong></p>
+          </div>
         </div>
 
         <ErrorMessage message={error} />
 
-        <div style={{ marginTop: "1rem" }}>
-          <button className="btn btn-secondary" onClick={addLine}>
-            + Añadir Producto
-          </button>
-          <button
-            className="btn btn-primary"
-            onClick={createInvoice}
-            style={{ marginLeft: "1rem" }}
-          >
-            ✅ Crear Factura
-          </button>
+        <div style={{ display: "flex", gap: "10px", marginTop: "1rem" }}>
+          <button className="btn btn-success" onClick={addLine}>+ Añadir Producto</button>
+          <button className="btn btn-primary" onClick={createInvoice}>Crear Factura</button>
         </div>
 
         {createdInvoice && (
           <div style={{ marginTop: "2rem" }}>
-            <h4>Factura creada: #{createdInvoice.id}</h4>
-            <h4>Total con IVA: <strong>{createdInvoice.total.toFixed(2)} €</strong></h4>
-            <button className="btn btn-primary" onClick={downloadPdf}>
-              📄 Descargar PDF
-            </button>
+            <h4>Factura #{createdInvoice.id} creada correctamente</h4>
+            <p><strong>Total:</strong> {createdInvoice.total.toFixed(2)} €</p>
+            <button className="btn btn-primary" onClick={downloadPdf}>📄 Descargar PDF</button>
           </div>
         )}
       </div>
diff --git a/memberflow-frontend/src/components/forms/InvoiceLineItem.jsx b/memberflow-frontend/src/components/forms/InvoiceLineItem.jsx
index c71ab8d..926a097 100644
--- a/memberflow-frontend/src/components/forms/InvoiceLineItem.jsx
+++ b/memberflow-frontend/src/components/forms/InvoiceLineItem.jsx
@@ -8,47 +8,51 @@ const InvoiceLineItem = ({ index, line, products, onUpdate, onRemove }) => {
   const selectedProduct = products.find(p => p.id === parseInt(line.productServiceId));
   const quantity = parseInt(line.quantity) || 1;
   const price = selectedProduct?.price || 0;
-  const ivaPercentage = selectedProduct?.ivaType?.percentage || 0;
-  const totalConIVA = price * quantity * (1 + ivaPercentage / 100);
+  const iva = selectedProduct?.ivaType?.percentage || 0;
+  const totalConIVA = price * quantity * (1 + iva / 100);
 
   return (
-    <div className="content-area" style={{ marginBottom: "1rem", display: "flex", flexDirection: "column", gap: "0.5rem" }}>
-      <select
-        name="productServiceId"
-        value={line.productServiceId}
-        onChange={handleChange}
-        className="form-select"
-      >
-        <option value="">Selecciona producto</option>
-        {products.map(p => (
-          <option key={p.id} value={p.id}>
-            {p.name} - {p.price}€ ({p.type})
-          </option>
-        ))}
-      </select>
+    <div className="card" style={{ padding: "20px", marginBottom: "1rem" }}>
+      <div className="form-column">
+        <label>Producto</label>
+        <select
+          name="productServiceId"
+          value={line.productServiceId}
+          onChange={handleChange}
+          className="form-select"
+          required
+        >
+          <option value="">Selecciona producto</option>
+          {products.map((p) => (
+            <option key={p.id} value={p.id}>
+              {p.name} - {p.price}€ ({p.type})
+            </option>
+          ))}
+        </select>
 
-      <input
-        type="number"
-        name="quantity"
-        min="1"
-        value={line.quantity}
-        onChange={handleChange}
-        className="form-input"
-        placeholder="Cantidad"
-      />
+        <label>Cantidad</label>
+        <input
+          type="number"
+          name="quantity"
+          min="1"
+          value={line.quantity}
+          onChange={handleChange}
+          className="form-input"
+          required
+        />
 
-      {selectedProduct && (
-        <>
-          <div style={{ fontSize: '0.9rem', color: '#666' }}>
-            <strong>{selectedProduct.name}</strong>: {selectedProduct.description}
+        {selectedProduct && (
+          <div className="invoice-line-summary">
+            <p><strong>{selectedProduct.name}</strong>: {selectedProduct.description}</p>
+            <p><strong>IVA:</strong> {iva}%</p>
+            <p><strong>Total con IVA:</strong> {totalConIVA.toFixed(2)} €</p>
           </div>
-          <div style={{ fontSize: '0.9rem', color: '#333' }}>
-            <strong>Total con IVA:</strong> {totalConIVA.toFixed(2)} €
-          </div>
-        </>
-      )}
+        )}
 
-      <button className="btn btn-danger" onClick={() => onRemove(index)}>Eliminar producto</button>
+        <button className="btn btn-danger" onClick={() => onRemove(index)}>
+          ❌ Eliminar Producto
+        </button>
+      </div>
     </div>
   );
 };
diff --git a/memberflow-frontend/src/components/forms/PaymentForm.jsx b/memberflow-frontend/src/components/forms/PaymentForm.jsx
index 3b463d7..c0283a7 100644
--- a/memberflow-frontend/src/components/forms/PaymentForm.jsx
+++ b/memberflow-frontend/src/components/forms/PaymentForm.jsx
@@ -88,81 +88,82 @@ const PaymentForm = () => {
       <div className="card">
         <h2>Registrar Pago de una Factura</h2>
 
-        <label>Seleccionar estudiante:</label>
-        <select
-          className="form-select"
-          value={selectedUserId}
-          onChange={handleStudentChange}
-        >
-          <option value="">-- Selecciona un estudiante --</option>
-          {students.map((s) =>
-            s.user ? (
-              <option key={s.id} value={s.user.id}>
-                {s.user.name} {s.user.lastName} ({s.user.email})
-              </option>
-            ) : null
-          )}
-        </select>
-
-        {invoices.length > 0 && (
-          <>
-            <label>Seleccionar factura:</label>
-            <select
-              className="form-select"
-              value={selectedInvoiceId}
-              onChange={(e) => setSelectedInvoiceId(e.target.value)}
-            >
-              <option value="">-- Selecciona una factura --</option>
-              {invoices.map((inv) => (
-                <option key={inv.id} value={inv.id}>
-                  #{inv.id} - {new Date(inv.date).toLocaleDateString()} - Total:{" "}
-                  {inv.total.toFixed(2)} €
+        <form className="form-column" onSubmit={handleSubmit}>
+          <label>Seleccionar estudiante:</label>
+          <select
+            className="form-select"
+            value={selectedUserId}
+            onChange={handleStudentChange}
+            required
+          >
+            <option value="">-- Selecciona un estudiante --</option>
+            {students.map((s) =>
+              s.user ? (
+                <option key={s.id} value={s.user.id}>
+                  {s.user.name} {s.user.lastName} ({s.user.email})
                 </option>
-              ))}
-            </select>
-          </>
-        )}
+              ) : null
+            )}
+          </select>
 
-        {invoices.length === 0 && selectedUserId && (
-          <p style={{ marginTop: "1rem", color: "gray" }}>
-            No hay facturas pendientes de pago para este estudiante.
-          </p>
-        )}
+          {invoices.length > 0 && (
+            <>
+              <label>Seleccionar factura:</label>
+              <select
+                className="form-select"
+                value={selectedInvoiceId}
+                onChange={(e) => setSelectedInvoiceId(e.target.value)}
+                required
+              >
+                <option value="">-- Selecciona una factura --</option>
+                {invoices.map((inv) => (
+                  <option key={inv.id} value={inv.id}>
+                    #{inv.id} - {new Date(inv.date).toLocaleDateString()} - Total: {inv.total.toFixed(2)} €
+                  </option>
+                ))}
+              </select>
+            </>
+          )}
 
-        {selectedInvoiceId && (
-          <>
-            <label>Importe pagado (€):</label>
-            <input
-              className="form-input"
-              type="number"
-              step="0.01"
-              value={amount}
-              onChange={(e) => setAmount(e.target.value)}
-            />
+          {invoices.length === 0 && selectedUserId && (
+            <p className="text-muted">
+              No hay facturas pendientes de pago para este estudiante.
+            </p>
+          )}
 
-            <label>Método de pago:</label>
-            <select
-              className="form-select"
-              value={paymentMethod}
-              onChange={(e) => setPaymentMethod(e.target.value)}
-            >
-              <option value="CASH">Efectivo</option>
-              <option value="CREDIT_CARD">Tarjeta</option>
-              <option value="BANK_TRANSFER">Transferencia</option>
-            </select>
+          {selectedInvoiceId && (
+            <>
+              <label>Importe pagado (€):</label>
+              <input
+                className="form-input"
+                type="number"
+                step="0.01"
+                value={amount}
+                onChange={(e) => setAmount(e.target.value)}
+                required
+              />
 
-            <ErrorMessage message={error} type="error" />
-            <ErrorMessage message={success} type="success" />
+              <label>Método de pago:</label>
+              <select
+                className="form-select"
+                value={paymentMethod}
+                onChange={(e) => setPaymentMethod(e.target.value)}
+                required
+              >
+                <option value="CASH">Efectivo</option>
+                <option value="CREDIT_CARD">Tarjeta</option>
+                <option value="BANK_TRANSFER">Transferencia</option>
+              </select>
 
-            <button
-              className="btn btn-primary"
-              style={{ marginTop: "1rem" }}
-              onClick={handleSubmit}
-            >
-              💳 Confirmar Pago
-            </button>
-          </>
-        )}
+              <ErrorMessage message={error} type="error" />
+              <ErrorMessage message={success} type="success" />
+
+              <button type="submit" className="btn btn-primary">
+                💳 Confirmar Pago
+              </button>
+            </>
+          )}
+        </form>
       </div>
     </div>
   );
diff --git a/memberflow-frontend/src/components/layout/MainLayout.jsx b/memberflow-frontend/src/components/layout/MainLayout.jsx
index 9cde849..3b125ad 100644
--- a/memberflow-frontend/src/components/layout/MainLayout.jsx
+++ b/memberflow-frontend/src/components/layout/MainLayout.jsx
@@ -24,7 +24,6 @@ import MembershipList from '../lists/MembershipList';
 import InvoiceForm from '../forms/InvoiceForm';
 import InvoiceList from '../lists/InvoiceList';
 import PaymentForm from '../forms/PaymentForm';
-import PaymentList from '../lists/PaymentList';
 import ProductForm from '../forms/ProductForm';
 import ProductList from '../lists/ProductList';
 import IVATypeManager from '../forms/IVATypeManager';
@@ -67,7 +66,6 @@ const MainLayout = () => {
             <Route path="/admin/finance/invoices/create" element={<InvoiceForm />} />
             <Route path="/admin/finance/invoices/list" element={<InvoiceList />} />
             <Route path="/admin/finance/payments/create" element={<PaymentForm />} />
-            <Route path="/admin/finance/payments/list" element={<PaymentList />} />
             <Route path="/admin/finance/products/create" element={<ProductForm />} />
             <Route path="/admin/finance/products/list" element={<ProductList />} />
             <Route path="/admin/finance/ivatypes/create" element={<IVATypeManager />} />
diff --git a/memberflow-frontend/src/components/layout/SidebarAdmin.jsx b/memberflow-frontend/src/components/layout/SidebarAdmin.jsx
index 288f6de..9727f08 100644
--- a/memberflow-frontend/src/components/layout/SidebarAdmin.jsx
+++ b/memberflow-frontend/src/components/layout/SidebarAdmin.jsx
@@ -40,7 +40,6 @@ const SidebarAdmin = () => {
           <button onClick={() => navigate('/admin/finance/invoices/create')}>🧾 Crear Factura</button>
           <button onClick={() => navigate('/admin/finance/invoices/list')}>📄 Ver Facturas</button>
           <button onClick={() => navigate('/admin/finance/payments/create')}>📄 Nuevo Pago</button>
-          <button onClick={() => navigate('/admin/finance/payments/list')}>💳 Facturas Pagadas</button>
           <button onClick={() => navigate('/admin/finance/products/create')}>🛒 Añadir Productos</button>
           <button onClick={() => navigate('/admin/finance/products/list')}>📦 Ver Productos</button>
           <button onClick={() => navigate('/admin/finance/ivatypes/create')}>💱 Añadir Tipo de IVA</button>
diff --git a/memberflow-frontend/src/components/lists/ProductList.jsx b/memberflow-frontend/src/components/lists/ProductList.jsx
index cbb8ce3..c437baf 100644
--- a/memberflow-frontend/src/components/lists/ProductList.jsx
+++ b/memberflow-frontend/src/components/lists/ProductList.jsx
@@ -1,5 +1,6 @@
 import React, { useEffect, useState } from "react";
 import api from "../../api/axiosConfig";
+import ErrorMessage from "../common/ErrorMessage";
 import "../styles/ContentArea.css";
 
 const ProductList = () => {
@@ -7,29 +8,35 @@ const ProductList = () => {
   const [ivaTypes, setIvaTypes] = useState([]);
   const [editIndex, setEditIndex] = useState(null);
   const [editableProduct, setEditableProduct] = useState(null);
-
-  const fetchProducts = async () => {
-    const res = await api.get("/products-services/getAll");
-    setProducts(res.data);
-  };
-
-  const fetchIvaTypes = async () => {
-    const res = await api.get("/iva-types/getAll");
-    setIvaTypes(res.data);
-  };
+  const [errorMsg, setErrorMsg] = useState("");
+  const [successMsg, setSuccessMsg] = useState("");
 
   useEffect(() => {
     fetchProducts();
     fetchIvaTypes();
   }, []);
 
-  useEffect(() => {
-  console.log("IVA Types cargados:", ivaTypes);
-}, [ivaTypes]);
+  const fetchProducts = async () => {
+    try {
+      const res = await api.get("/products-services/getAll");
+      setProducts(res.data);
+    } catch (err) {
+      setErrorMsg("❌ Error al cargar los productos.");
+    }
+  };
+
+  const fetchIvaTypes = async () => {
+    try {
+      const res = await api.get("/iva-types/getAll");
+      setIvaTypes(res.data);
+    } catch (err) {
+      setErrorMsg("❌ Error al cargar tipos de IVA.");
+    }
+  };
 
   const startEdit = (index) => {
     setEditIndex(index);
-    setEditableProduct({ ...products[index] }); // contiene ivaTypeId directamente
+    setEditableProduct({ ...products[index] });
   };
 
   const cancelEdit = () => {
@@ -47,152 +54,145 @@ const ProductList = () => {
   const handleSave = async () => {
     try {
       const dto = {
-        id: editableProduct.id,
-        name: editableProduct.name,
-        price: parseFloat(editableProduct.price),
-        type: editableProduct.type,
-        status: editableProduct.status,
-        ivaTypeId: editableProduct.ivaTypeId,
+        ...editableProduct,
+        price: parseFloat(editableProduct.price)
       };
-
       await api.put("/products-services/update", dto);
-      alert("✅ Producto actualizado correctamente.");
-      setEditIndex(null);
-      setEditableProduct(null);
+      setSuccessMsg("✅ Producto actualizado correctamente.");
+      setErrorMsg("");
+      cancelEdit();
       fetchProducts();
     } catch (err) {
-      console.error(err);
-      alert("❌ Error al actualizar el producto.");
+      setErrorMsg("❌ Error al actualizar el producto.");
     }
   };
 
   const handleDelete = async (id) => {
-    if (window.confirm("¿Estás seguro de que deseas eliminar este producto?")) {
-      await api.delete(`/products-services/deleteById/${id}`);
-      fetchProducts();
+    if (window.confirm("¿Seguro que quieres eliminar este producto?")) {
+      try {
+        await api.delete(`/products-services/deleteById/${id}`);
+        fetchProducts();
+        setSuccessMsg("✅ Producto eliminado correctamente.");
+        setErrorMsg("");
+      } catch {
+        setErrorMsg("❌ Error al eliminar el producto.");
+      }
     }
   };
 
- const getIVADisplay = (ivaTypeId) => {
-  const iva = ivaTypes.find((i) => i.id === Number(ivaTypeId));
-  return iva ? `${iva.percentage}%` : "Sin IVA";
-};
-
+  const getIVADisplay = (ivaTypeId) => {
+    const iva = ivaTypes.find((i) => i.id === Number(ivaTypeId));
+    return iva?.percentage ? `${iva.percentage}%` : "";
+  };
 
   return (
-    <div className="content-area">
+    <div className="card">
       <h2>Lista de Productos y Servicios</h2>
+      <ErrorMessage message={errorMsg} type="error" />
+      <ErrorMessage message={successMsg} type="success" />
 
-      <table className="table" style={{ marginTop: "2rem" }}>
-        <thead>
-          <tr>
-            <th>ID</th>
-            <th>Nombre</th>
-            <th>Precio</th>
-            <th>IVA</th>
-            <th>Tipo</th>
-            <th>Estado</th>
-            <th>Acciones</th>
-          </tr>
-        </thead>
-        <tbody>
-          {products.map((p, index) => {
-            const isEditing = index === editIndex;
-            return (
-              <tr key={p.id}>
-                <td>{p.id}</td>
-                <td>
-                  {isEditing ? (
-                    <input
-                      type="text"
-                      value={editableProduct.name}
-                      onChange={(e) => handleChange("name", e.target.value)}
-                    />
-                  ) : (
-                    p.name
-                  )}
-                </td>
-                <td>
-                  {isEditing ? (
-                    <input
-                      type="number"
-                      value={editableProduct.price}
-                      step="0.01"
-                      onChange={(e) => handleChange("price", e.target.value)}
-                    />
-                  ) : (
-                    `${p.price.toFixed(2)} €`
-                  )}
-                </td>
-                <td>
-                  {isEditing ? (
-                    <select
-                      value={editableProduct.ivaTypeId || ""}
-                      onChange={(e) => handleChange("ivaTypeId", e.target.value)}
-                    >
-                      <option value="">-- IVA --</option>
-                      {ivaTypes.map((iva) => (
-                        <option key={iva.id} value={iva.id}>
-                          {iva.name} ({iva.percentage}%)
-                        </option>
-                      ))}
-                    </select>
-                  ) : (
-                    getIVADisplay(p.ivaTypeId)
-                  )}
-                </td>
-                <td>
-                  {isEditing ? (
-                    <select
-                      value={editableProduct.type}
-                      onChange={(e) => handleChange("type", e.target.value)}
-                    >
-                      <option value="PRODUCT">Producto</option>
-                      <option value="SERVICE">Servicio</option>
-                    </select>
-                  ) : (
-                    p.type
-                  )}
-                </td>
-                <td>
-                  {isEditing ? (
-                    <select
-                      value={editableProduct.status}
-                      onChange={(e) => handleChange("status", e.target.value)}
-                    >
-                      <option value="ACTIVE">Activo</option>
-                      <option value="INACTIVE">Inactivo</option>
-                    </select>
-                  ) : (
-                    p.status
-                  )}
-                </td>
-                <td>
-                  {isEditing ? (
-                    <>
-                      <button className="btn btn-primary btn-sm" onClick={handleSave}>
-                        💾 Guardar
-                      </button>
-                      <button className="btn btn-secondary btn-sm" onClick={cancelEdit}>
-                        ❌ Cancelar
-                      </button>
-                    </>
-                  ) : (
-                    <>
-                      <button className="btn btn-secondary btn-sm" onClick={() => startEdit(index)}>
-                        ✏️ Editar
-                      </button>
-                      <button className="btn btn-danger btn-sm" onClick={() => handleDelete(p.id)}>
-                        🗑️ Eliminar
-                      </button>
-                    </>
-                  )}
-                </td>
-              </tr>
-            );
-          })}
-        </tbody>
-      </table>
+      <div className="table-wrapper">
+        <table className="styled-table">
+          <thead>
+            <tr>
+              <th>Nombre</th>
+              <th>Precio (€)</th>
+              <th>IVA</th>
+              <th>Tipo</th>
+              <th>Estado</th>
+              <th>Acciones</th>
+            </tr>
+          </thead>
+          <tbody>
+            {products.map((p, index) => {
+              const isEditing = index === editIndex;
+              return (
+                <tr key={p.id}>
+                  <td>
+                    {isEditing ? (
+                      <input
+                        type="text"
+                        value={editableProduct.name}
+                        onChange={(e) => handleChange("name", e.target.value)}
+                      />
+                    ) : (
+                      p.name
+                    )}
+                  </td>
+                  <td>
+                    {isEditing ? (
+                      <input
+                        type="number"
+                        step="0.01"
+                        value={editableProduct.price}
+                        onChange={(e) => handleChange("price", e.target.value)}
+                      />
+                    ) : (
+                      `${p.price.toFixed(2)} €`
+                    )}
+                  </td>
+                  <td>
+                    {isEditing ? (
+                      <select
+                        value={editableProduct.ivaTypeId || ""}
+                        onChange={(e) => handleChange("ivaTypeId", e.target.value)}
+                      >
+                        <option value="">-- IVA --</option>
+                        {ivaTypes.map((iva) => (
+                          <option key={iva.id} value={iva.id}>
+                            {iva.percentage}%
+                          </option>
+                        ))}
+                      </select>
+                    ) : (
+                      getIVADisplay(p.ivaTypeId)
+                    )}
+                  </td>
+                  <td>
+                    {isEditing ? (
+                      <select
+                        value={editableProduct.type}
+                        onChange={(e) => handleChange("type", e.target.value)}
+                      >
+                        <option value="PRODUCT">Producto</option>
+                        <option value="SERVICE">Servicio</option>
+                      </select>
+                    ) : (
+                      p.type
+                    )}
+                  </td>
+                  <td>
+                    {isEditing ? (
+                      <select
+                        value={editableProduct.status}
+                        onChange={(e) => handleChange("status", e.target.value)}
+                      >
+                        <option value="ACTIVE">Activo</option>
+                        <option value="INACTIVE">Inactivo</option>
+                      </select>
+                    ) : (
+                      p.status
+                    )}
+                  </td>
+                  <td>
+                    {isEditing ? (
+                      <>
+                        <button className="edit-btn" onClick={handleSave}>💾</button>
+                        <button className="delete-btn" onClick={cancelEdit}>❌</button>
+                      </>
+                    ) : (
+                      <>
+                        <button className="edit-btn" onClick={() => startEdit(index)}>✏️</button>
+                        <button className="delete-btn" onClick={() => handleDelete(p.id)}>🗑️</button>
+                      </>
+                    )}
+                  </td>
+                </tr>
+              );
+            })}
+          </tbody>
+        </table>
+      </div>
     </div>
   );
 };
diff --git a/memberflow-frontend/src/components/styles/ContentArea.css b/memberflow-frontend/src/components/styles/ContentArea.css
index 2c0bb3d..7ab2780 100644
--- a/memberflow-frontend/src/components/styles/ContentArea.css
+++ b/memberflow-frontend/src/components/styles/ContentArea.css
@@ -202,20 +202,6 @@ ul li button:hover {
   background-color: #c0392b;
 }
 
-.add-button {
-  padding: 6px 12px;
-  border: none;
-  border-radius: 8px;
-  background-color: #2ecc71;
-  color: white;
-  cursor: pointer;
-  transition: background-color 0.3s;
-}
-
-.add-button:hover {
-  background-color: #27ae60;
-}
-
 .form-column {
   display: flex;
   flex-direction: column;
@@ -308,6 +294,83 @@ form textarea:focus {
   color: #7f8c8d;
 }
 
+.invoice-summary {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+  gap: 20px;
+  margin-top: 20px;
+  padding: 20px;
+  background-color: #f0f4f8;
+  border-radius: 12px;
+}
+
+.invoice-line-summary {
+  background-color: #ecf0f1;
+  padding: 12px;
+  border-radius: 10px;
+  margin-top: 10px;
+  margin-bottom: 10px;
+  font-size: 15px;
+  color: #2d3436;
+}
+
+/* Botones generales */
+
+.add-button {
+  padding: 6px 12px;
+  border: none;
+  border-radius: 8px;
+  background-color: #2ecc71;
+  color: white;
+  cursor: pointer;
+  transition: background-color 0.3s;
+}
+
+.add-button:hover {
+  background-color: #27ae60;
+}
+
+.btn {
+  padding: 6px 12px;
+  border: none;
+  border-radius: 8px;
+  font-weight: bold;
+  cursor: pointer;
+  transition: background-color 0.3s, transform 0.2s;
+}
+
+/* Botón primario (azul) */
+.btn-primary {
+  background-color: #0984e3;
+  color: white;
+}
+
+.btn-primary:hover {
+  background-color: #74b9ff;
+  transform: translateY(-2px);
+}
+
+/* Botón de peligro (rojo) */
+.btn-danger {
+  background-color: #e74c3c;
+  color: white;
+}
+
+.btn-danger:hover {
+  background-color: #c0392b;
+  transform: translateY(-2px);
+}
+
+/* Botón de éxito (verde) */
+.btn-success {
+  background-color: #2ecc71;
+  color: white;
+}
+
+.btn-success:hover {
+  background-color: #27ae60;
+  transform: translateY(-2px);
+}
 
 
 
diff --git a/memberflow-frontend/src/components/styles/Sidebar.css b/memberflow-frontend/src/components/styles/Sidebar.css
index 9ad3338..4909083 100644
--- a/memberflow-frontend/src/components/styles/Sidebar.css
+++ b/memberflow-frontend/src/components/styles/Sidebar.css
@@ -7,6 +7,7 @@
   height: 100vh;
   display: flex;
   flex-direction: column;
+  overflow: hidden; /* Evita overflow exterior */
 }
 
 
@@ -15,6 +16,7 @@
   font-size: 1.1rem;
   font-weight: 600;
   color: #0984e3;
+  margin: 0;
 }
 
 .sidebar button {
@@ -40,9 +42,18 @@
 .sidebar-scroll {
   flex: 1;
   overflow-y: auto;
-  padding: 0 20px 20px;
+  padding: 0 20px 80px; /* MÁS espacio inferior */
   display: flex;
   flex-direction: column;
   gap: 10px;
   min-height: 0;
+}
+
+/* Opcional: para asegurar buen scroll en todos los navegadores */
+.sidebar-scroll::-webkit-scrollbar {
+  width: 6px;
+}
+.sidebar-scroll::-webkit-scrollbar-thumb {
+  background-color: rgba(0, 0, 0, 0.2);
+  border-radius: 4px;
 }
\ No newline at end of file
diff --git a/memberflow-frontend/src/pages/admin/AdminDashboard.jsx b/memberflow-frontend/src/pages/admin/AdminDashboard.jsx
index f7568f8..1f3ce9e 100644
--- a/memberflow-frontend/src/pages/admin/AdminDashboard.jsx
+++ b/memberflow-frontend/src/pages/admin/AdminDashboard.jsx
@@ -5,29 +5,60 @@ import '../../components/styles/DashboardCards.css';
 const AdminDashboard = () => {
   const navigate = useNavigate();
 
-  const options = [
-    { title: '➕ Crear Usuario', route: '/admin/user-management/users/create' },
-    { title: '📜 Listar Usuarios', route: '/admin/user-management/users/list' },
-    { title: '🔔 Crear Notificación', route: '/admin/user-management/notifications/create' },
-    { title: '🕓 Crear Historial', route: '/admin/user-management/student-history/create' },
-    { title: '📜 Ver Historial', route: '/admin/user-management/student-history/list' },
-    { title: '🎓 Gestión Estudiantes', route: '/admin/user-management/students' },
-    { title: '👨‍🏫 Gestión Profesores', route: '/admin/user-management/teachers' },
-    { title: '🛡️ Gestión Admins', route: '/admin/user-management/admins' },
-    { title: '📚 Gestión de Clases', route: '/admin/class-management' },
-    { title: '💰 Finanzas', route: '/admin/finance' }
+  const sections = [
+    {
+      title: '👥 Administración de Usuarios',
+      options: [
+        { title: '➕ Crear Usuario', route: '/admin/user-management/users/create' },
+        { title: '📋 Ver Usuarios', route: '/admin/user-management/users/list' },
+        { title: '🔔 Crear Notificación', route: '/admin/user-management/notifications/create' },
+        { title: '📨 Ver Notificaciones', route: '/admin/user-management/notifications/list' },
+        { title: '🕒 Crear Historial', route: '/admin/user-management/student-history/create' },
+        { title: '📜 Ver Historial', route: '/admin/user-management/student-history/list' },
+      ]
+    },
+    {
+      title: '📚 Administración de Clases',
+      options: [
+        { title: '➕ Crear Grupo', route: '/admin/class-management/training-groups/create' },
+        { title: '👥 Ver Grupos', route: '/admin/class-management/training-groups/list' },
+        { title: '🧑‍🏫 Administrar Grupos', route: '/admin/class-management/training-groups/manage-students' },
+        { title: '🗓️ Ver Horario', route: '/admin/class-management/training-groups/view-timetable' },
+        { title: '📆 Ver Sesiones', route: '/admin/class-management/training-session/list' },
+        { title: '📝 Registrar Asistencia', route: '/admin/class-management/assistance/create' },
+        { title: '📋 Ver Asistencias', route: '/admin/class-management/assistance/list' },
+        { title: '➕ Detalles de las Membresías', route: '/admin/class-management/memberships/details' },
+        { title: '🏷️ Asignar Membresías', route: '/admin/class-management/memberships/list' },
+      ]
+    },
+    {
+      title: '💵 Finanzas',
+      options: [
+        { title: '🧾 Crear Factura', route: '/admin/finance/invoices/create' },
+        { title: '📄 Ver Facturas', route: '/admin/finance/invoices/list' },
+        { title: '📄 Nuevo Pago', route: '/admin/finance/payments/create' },
+        { title: '🛒 Añadir Productos', route: '/admin/finance/products/create' },
+        { title: '📦 Ver Productos', route: '/admin/finance/products/list' },
+        { title: '💱 Añadir Tipo de IVA', route: '/admin/finance/ivatypes/create' },
+      ]
+    },
   ];
 
   return (
     <div className="dashboard">
       <h2>Panel de Control del Administrador</h2>
-      <div className="card-grid">
-        {options.map((opt, index) => (
-          <div key={index} className="dashboard-card" onClick={() => navigate(opt.route)}>
-            {opt.title}
+      {sections.map((section, index) => (
+        <div key={index} className="dashboard-section">
+          <h3>{section.title}</h3>
+          <div className="card-grid">
+            {section.options.map((opt, idx) => (
+              <div key={idx} className="dashboard-card" onClick={() => navigate(opt.route)}>
+                {opt.title}
+              </div>
+            ))}
           </div>
-        ))}
-      </div>
+        </div>
+      ))}
     </div>
   );
 };