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

html, body {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #f0f0f0;
  font-family: Arial, sans-serif;
}

#app {
  width: 400px;
  background: white;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  overflow: hidden;
}

/* Панель вкладок */
.tabs {
  display: flex;
  background: #e9e9e9;
}

.tab-button {
  flex: 1;
  padding: 12px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 16px;
  transition: background 0.2s;
}

.tab-button:hover {
  background: #dcdcdc;
}

.tab-button.active {
  background: white;
  border-bottom: 3px solid #3498db;
  font-weight: bold;
}

/* Содержимое вкладок */
.tab-content {
  display: none;
  padding: 20px;
}

.tab-content.active {
  display: block;
}

/* Вертикально расположенные кнопки */
.buttons-vertical {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 20px;
}

.action-button {
  padding: 12px;
  font-size: 16px;
  cursor: pointer;
  border: 1px solid #bbb;
  border-radius: 6px;
  background-color: #f8f8f8;
  transition: background-color 0.2s, border-color 0.2s;
}

.action-button:hover {
  background-color: #e2e6ea;
  border-color: #999;
}

.close-button {
  background-color: #e74c3c;
  color: white;
  border-color: #c0392b;
}

.close-button:hover {
  background-color: #c0392b;
}

/* Панель частоты */
#frequency-panel {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 14px;
  background-color: #f9f9f9;
  border: 1px solid #ddd;
  border-radius: 6px;
  margin-bottom: 10px;
}

#frequency-label {
  font-weight: bold;
  color: #555;
}

#frequency-value {
  font-size: 18px;
  color: #2c3e50;
}

/* Панель статуса */
#status-panel {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background-color: #f9f9f9;
  border: 1px solid #ddd;
  border-radius: 6px;
}

.indicator {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  display: inline-block;
}

.indicator-red {
  background-color: #e74c3c;
}

.indicator-green {
  background-color: #2ecc71;
}

#status-text {
  font-size: 16px;
  color: #333;
}

/* Модальное окно */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.4);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

.modal.hidden {
  display: none;
}

.modal-content {
  background: white;
  padding: 20px;
  border-radius: 8px;
  width: 300px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.3);
  position: relative;
}

.close-modal {
  position: absolute;
  top: 10px;
  right: 15px;
  font-size: 22px;
  cursor: pointer;
  color: #777;
}

.close-modal:hover {
  color: #333;
}

.modal-content h3 {
  margin-bottom: 15px;
  text-align: center;
}

.freq-input-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 15px;
}

.freq-btn {
  width: 40px;
  height: 40px;
  font-size: 20px;
  background: #3498db;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.2s;
}

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

#freq-input {
  width: 100px;
  padding: 8px;
  font-size: 18px;
  text-align: center;
  border: 1px solid #ccc;
  border-radius: 4px;
}

#btn-set-freq {
  display: block;
  width: 100%;
  margin-top: 10px;
}

.error-msg {
  color: #e74c3c;
  margin-top: 8px;
  text-align: center;
  font-size: 14px;
}

.error-msg.hidden {
  display: none;
}