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

:root {
  --bg: #000000;
  --text: #FFFFFF;
  --text-dim: #888888;
  --accent: #FFD700;
  --border: #333333;
  --font: 'Courier New', Courier, 'Roboto Mono', monospace;
}

html {
  font-size: 16px;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.4;
  min-height: 100vh;
  min-height: 100dvh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  max-width: 600px;
  margin: 0 auto;
  padding: 1rem;
  padding-bottom: 4rem;
}

/* HEADER */
header {
  border-bottom: 2px solid var(--accent);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}

h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--accent);
  margin-bottom: 0.25rem;
}

#date-display {
  font-size: 0.875rem;
  color: var(--text-dim);
  text-transform: uppercase;
}

#storage-status {
  font-size: 0.75rem;
  color: var(--text-dim);
  padding: 1rem;
  padding-bottom: 0;
}

#storage-status.persisted {
  color: var(--accent);
}

/* PROGRESS */
#progress-section {
  margin-bottom: 1.5rem;
}

#progress-bar {
  height: 8px;
  background-color: var(--border);
  border: 1px solid var(--text-dim);
}

#progress-fill {
  height: 100%;
  width: 0%;
  background-color: var(--accent);
}

#progress-text {
  font-size: 0.875rem;
  color: var(--text-dim);
  margin-top: 0.5rem;
  text-align: right;
}

/* HABITS LIST */
#habits-section {
  margin-bottom: 1.5rem;
}

#habits-list {
  list-style: none;
}

.habit-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  border: 1px solid var(--border);
  margin-bottom: -1px;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

.habit-item:active {
  background-color: var(--border);
}

.habit-item.completed {
  opacity: 0.5;
}

.habit-item.completed .habit-title {
  text-decoration: line-through;
  color: var(--text-dim);
}

.habit-check {
  width: 24px;
  height: 24px;
  border: 2px solid var(--text-dim);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.habit-item.completed .habit-check {
  border-color: var(--accent);
  color: var(--accent);
}

.habit-title {
  font-size: 1rem;
  flex: 1;
  word-break: break-word;
}

.empty-state {
  color: var(--text-dim);
  text-align: center;
  padding: 2rem;
  border: 1px dashed var(--border);
  font-size: 0.875rem;
}

/* ADD INPUT */
#add-section {
  margin-bottom: 2rem;
}

#habit-input {
  width: 100%;
  padding: 1rem;
  background-color: var(--bg);
  border: 2px solid var(--border);
  color: var(--text);
  font-family: var(--font);
  font-size: 1rem;
}

#habit-input:focus {
  outline: none;
  border-color: var(--accent);
}

#habit-input::placeholder {
  color: var(--text-dim);
}

/* HEATMAP */
#heatmap-section {
  margin-bottom: 2rem;
}

#heatmap-section h2 {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-dim);
  margin-bottom: 1rem;
  letter-spacing: 0.1em;
}

#heatmap {
  display: grid;
  grid-template-columns: repeat(53, 1fr);
  gap: 2px;
}

.heatmap-cell {
  aspect-ratio: 1;
  border: 1px solid var(--border);
  min-width: 0;
}

.heatmap-cell[data-level="0"] {
  background-color: transparent;
}

.heatmap-cell[data-level="1"] {
  background-color: rgba(255, 215, 0, 0.2);
  border-color: rgba(255, 215, 0, 0.3);
}

.heatmap-cell[data-level="2"] {
  background-color: rgba(255, 215, 0, 0.4);
  border-color: rgba(255, 215, 0, 0.5);
}

.heatmap-cell[data-level="3"] {
  background-color: rgba(255, 215, 0, 0.6);
  border-color: rgba(255, 215, 0, 0.7);
}

.heatmap-cell[data-level="4"] {
  background-color: rgba(255, 215, 0, 0.8);
  border-color: rgba(255, 215, 0, 0.9);
}

.heatmap-cell[data-level="5"] {
  background-color: var(--accent);
  border-color: var(--accent);
}

.heatmap-cell.future {
  opacity: 0.3;
}

/* DATA MANAGEMENT */
#data-management {
  border: 1px solid var(--border);
  margin-top: 2rem;
}

#data-management summary {
  padding: 1rem;
  cursor: pointer;
  font-size: 0.875rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  user-select: none;
  -webkit-user-select: none;
}

#data-management summary:hover {
  color: var(--text);
}

#data-management[open] summary {
  border-bottom: 1px solid var(--border);
}

.data-controls {
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.data-controls button,
#import-label {
  width: 100%;
  padding: 0.875rem 1rem;
  background-color: var(--bg);
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.875rem;
  cursor: pointer;
  text-align: center;
  letter-spacing: 0.05em;
}

.data-controls button:hover,
#import-label:hover {
  border-color: var(--text-dim);
  color: var(--text);
}

#import-label {
  display: block;
}

#import-input {
  display: none;
}

#clear-btn {
  border-color: #660000;
  color: #AA0000;
}

#clear-btn:hover {
  border-color: #AA0000;
  color: #FF0000;
}

/* DIALOG */
dialog {
  background-color: var(--bg);
  border: 2px solid var(--accent);
  color: var(--text);
  font-family: var(--font);
  padding: 0;
  max-width: 90vw;
  width: 300px;
}

dialog::backdrop {
  background-color: rgba(0, 0, 0, 0.85);
}

#dialog-title {
  font-size: 0.875rem;
  font-weight: 400;
  padding: 1rem;
  border-bottom: 1px solid var(--border);
  letter-spacing: 0.1em;
  color: var(--text-dim);
}

.dialog-buttons {
  display: flex;
  flex-direction: column;
}

.dialog-buttons button {
  width: 100%;
  padding: 1rem;
  background-color: var(--bg);
  border: none;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  font-family: var(--font);
  font-size: 1rem;
  cursor: pointer;
  text-align: left;
}

.dialog-buttons button:last-child {
  border-bottom: none;
}

.dialog-buttons button:hover {
  background-color: var(--border);
}

#delete-btn {
  color: #FF0000;
}

#cancel-btn {
  color: var(--text-dim);
}

/* RESPONSIVE */
@media (max-width: 400px) {
  main {
    padding: 0.75rem;
  }

  h1 {
    font-size: 1.25rem;
  }

  .habit-item {
    padding: 0.875rem;
  }

  #heatmap {
    gap: 1px;
  }
}

@media (min-width: 600px) {
  #heatmap {
    gap: 3px;
  }

  .heatmap-cell {
    border-width: 2px;
  }
}