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

body {
  font-family: system-ui, -apple-system, sans-serif;
  background-color: #111827;
  color: white;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: 400px;
  padding: 2rem;
}

.mode-switcher {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
}

.nav-btn,
.mode-btn {
  background-color: #1f2937;
  border: none;
  color: #9ca3af;
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.nav-btn:hover,
.mode-btn:hover {
  background-color: #374151;
  color: white;
}

.mode-btn.active {
  background-color: #6366f1;
  color: white;
}

.timer {
  position: relative;
  width: 300px;
  height: 300px;
  margin: 0 auto;
}

.progress-ring {
  transform: rotate(-90deg);
}

.progress-ring__circle-bg {
  fill: transparent;
  stroke: #374151;
  stroke-width: 8;
}

.progress-ring__circle {
  fill: transparent;
  stroke: #6366f1;
  stroke-width: 8;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.5s ease;
}

.timer-display {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

#time {
  font-size: 3.75rem;
  font-weight: bold;
}

.controls {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 2rem;
}

.btn {
  background-color: #6366f1;
  border: none;
  color: white;
  width: 3rem;
  height: 3rem;
  border-radius: 9999px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s;
}

.btn:hover {
  background-color: #4f46e5;
}

.btn:not(:first-child) {
  background-color: #374151;
}

.btn:not(:first-child):hover {
  background-color: #4b5563;
}

.modal {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
}

.modal.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-content {
  background-color: #1f2937;
  padding: 1.5rem;
  border-radius: 0.5rem;
  width: 100%;
  max-width: 400px;
  position: relative;
  margin: 1rem;
}

.close-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  color: #9ca3af;
  cursor: pointer;
  padding: 0.5rem;
}

.close-btn:hover {
  color: white;
}

h2 {
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1.5rem;
}

.form-group {
  margin-bottom: 1rem;
}

label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
}

input[type="number"],
input[type="range"],
select {
  width: 100%;
  padding: 0.5rem 0.75rem;
  background-color: #374151;
  border: none;
  border-radius: 0.25rem;
  color: white;
  font-size: 1rem;
}

input[type="range"] {
  padding: 0;
}

select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
  background-position: right 0.5rem center;
  background-repeat: no-repeat;
  background-size: 1.5em 1.5em;
  padding-right: 2.5rem;
}

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 1rem;
  margin-top: 1.5rem;
}

.btn-secondary,
.btn-primary {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 0.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
}

.btn-secondary {
  background: none;
  color: #9ca3af;
}

.btn-secondary:hover {
  color: white;
}

.btn-primary {
  background-color: #6366f1;
  color: white;
}

.btn-primary:hover {
  background-color: #4f46e5;
}