* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #f3f5f8;
  color: #263445;
  font-family: "Segoe UI", Arial, sans-serif;
}

.container {
  max-width: 1100px;
  margin: 35px auto;
  padding: 0 20px;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 25px;
}

h1 {
  margin: 0;
  font-size: 25px;
}

header p,
.send-area p {
  color: #718096;
  margin-bottom: 0;
}

.status {
  background: #e2e8f0;
  padding: 8px 13px;
  border-radius: 20px;
  font-size: 12px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
  margin-bottom: 20px;
}

.stat,
.panel {
  background: white;
  border-radius: 9px;
  padding: 20px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.stat span {
  display: block;
  color: #718096;
  font-size: 13px;
}

.stat strong {
  display: block;
  font-size: 27px;
  margin-top: 8px;
}

.panel {
  margin-bottom: 20px;
}

h2 {
  font-size: 17px;
  margin-top: 0;
}

.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
  margin-bottom: 15px;
}

label {
  display: block;
  margin-bottom: 7px;
  font-size: 13px;
  font-weight: 600;
}

input {
  width: 100%;
  padding: 11px;
  border: 1px solid #dce2ea;
  border-radius: 6px;
  font-size: 14px;
}

input:focus {
  outline: none;
  border-color: #3977c3;
}

.btn {
  border: none;
  border-radius: 6px;
  padding: 11px 17px;
  cursor: pointer;
  font-weight: 600;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: #2463a6;
  color: white;
}

.btn-secondary {
  background: #e8eef7;
  color: #24558a;
}

.btn-light {
  background: #f0f2f5;
  color: #44546a;
}

.section-heading,
.send-area {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 15px;
}

.table-container {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

th,
td {
  padding: 13px 10px;
  text-align: left;
  border-bottom: 1px solid #edf0f4;
}

th {
  color: #718096;
  font-weight: 600;
}

.estado {
  display: inline-block;
  padding: 5px 9px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
}

.estado-enviado {
  background: #dcfce7;
  color: #166534;
}

.estado-pendiente {
  background: #fef3c7;
  color: #92400e;
}

.send-area {
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px solid #edf0f4;
}

.mensaje {
  padding: 14px;
  margin-bottom: 20px;
  border-radius: 7px;
  background: #e0f2fe;
  color: #075985;
}

.mensaje.error {
  background: #fee2e2;
  color: #991b1b;
}

.hidden {
  display: none;
}

@media (max-width: 650px) {
  .stats {
    grid-template-columns: 1fr;
  }

  .form-grid {
    grid-template-columns: 1fr;
  }

  header,
  .section-heading,
  .send-area {
    align-items: stretch;
    flex-direction: column;
  }

  .send-area .btn {
    width: 100%;
  }
}