body {
  font-family: 'Poppins', Arial, sans-serif;
  margin: 20px;
  background: #f7f7f7;
}

header {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 10px;
}

#logo {
  width: 60px;
  height: auto;
}

.main-title {
  color: #e74c3c;
  font-weight: 700;
  font-size: 2rem;
}

#top-nav {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 20px;
}

.nav-btn {
  background: #cec10d;
  border: none;
  color: white;
  font-size: 14px;
  padding: 8px 16px;
  border-radius: 5px;
  cursor: pointer;
  font-weight: bold;
  transition: all 0.2s;
}

.nav-btn:hover {
  background: #2980b9;
}

.nav-btn.active {
  font-size: 16px;
  background-color: #f1c40f;
  transform: scale(1.05);
}

.container {
  display: flex;
  gap: 20px;
}

.left-column {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.right-column {
  flex: 2;
  display: flex;
  flex-direction: column;
  gap: 15px;
}

form, #resume, table {
  background: #fff;
  padding: 15px;
  border-radius: 8px;
}

#period-select label {
  display: block;
  margin-top: 10px;
}

input, select {
  width: 100%;
  padding: 6px;
  margin-top: 5px;
  margin-bottom: 10px;
  border-radius: 4px;
  border: 1px solid #ccc;
}

button {
  padding: 8px 12px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
}

.btn-add {
  background-color: #27ae60;
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  transition: all 0.2s;
}

.btn-add:hover {
  background-color: #2ecc71;
  transform: scale(1.05);
}

.btn-pdf {
  background-color: #2980b9;
  color: #fff;
}

.delete-btn {
  background-color: #c0392b;
  color: #fff;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 8px;
  border: 1px solid #ccc;
  text-align: left;
}

@media (max-width: 900px) {
  .container {
    flex-direction: column;
  }
  .left-column, .right-column {
    flex: unset;
  }
}