:root {
  --bg-color: #f7f9fc;
  --surface-color: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --border-color: #e2e8f0;
  --primary-color: #0f172a;
  --primary-hover: #334155;
  --danger-color: #ef4444;
  --accent-color: #3b82f6;
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --radius: 12px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
}

[data-theme='dark'] {
  --bg-color: #0f172a;
  --surface-color: #1e293b;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --border-color: #334155;
  --primary-color: #f8fafc;
  --primary-hover: #e2e8f0;
  --danger-color: #f87171;
  --accent-color: #60a5fa;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s, color 0.3s;
}

.app-container {
  max-width: 600px;
  margin: 0 auto;
  width: 100%;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  background-color: var(--bg-color);
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
  background-color: var(--surface-color);
  position: sticky;
  top: 0;
  z-index: 10;
}

#main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

h1,
h2,
h3,
h4 {
  font-weight: 600;
}

h1 {
  font-size: 1.5rem;
}

h2 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-sm);
}

h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-sm);
}

.hidden {
  display: none !important;
}

.active {
  display: block !important;
}

.view {
  display: none;
  padding: var(--spacing-lg);
  flex: 1;
  overflow-y: auto;
  padding-bottom: 80px;
  /* space for bottom nav */
}

/* Forms & Inputs */
.form-group {
  margin-bottom: var(--spacing-md);
}

label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

input[type="email"],
input[type="password"],
input[type="text"],
input[type="date"],
textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  background-color: var(--surface-color);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.2s;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* Sliders */
.slider-group {
  margin-bottom: var(--spacing-md);
}

.slider-labels {
  display: flex;
  justify-content: space-between;
  margin-bottom: 4px;
  font-size: 0.875rem;
}

.val-badge {
  background: var(--primary-color);
  color: var(--bg-color);
  padding: 2px 8px;
  border-radius: 12px;
  font-weight: bold;
}

.slider {
  -webkit-appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--border-color);
  outline: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent-color);
  cursor: pointer;
}

/* Buttons */
button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
  font-size: 1rem;
}

.btn-primary,
.btn-secondary {
  width: 100%;
  padding: 14px;
  border-radius: var(--radius);
  font-weight: 600;
  text-align: center;
  transition: opacity 0.2s;
}

.btn-primary {
  background-color: var(--primary-color);
  color: var(--bg-color);
  margin-bottom: var(--spacing-sm);
}

.btn-primary:active {
  opacity: 0.8;
}

.btn-secondary {
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.icon-btn {
  font-size: 1.25rem;
  padding: 8px;
  color: var(--text-secondary);
}

.text-danger {
  color: var(--danger-color);
}

.text-center {
  text-align: center;
}

.w-full {
  width: 100%;
}

.mb-1 {
  margin-bottom: var(--spacing-sm);
}

/* Dashboard & Cards */
.card,
.form-card,
.stat-card {
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.quick-stats,
.metrics-row {
  display: flex;
  justify-content: space-around;
  margin-top: var(--spacing-sm);
}

.stat-item {
  text-align: center;
  font-size: 1.25rem;
  font-weight: bold;
}

.view-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.date-display {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.flex-between {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-sm);
}

/* Lists */
.entries-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.entry-item {
  background-color: var(--surface-color);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  cursor: pointer;
}

.entry-item:hover {
  border-color: var(--text-secondary);
}

.entry-item-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 4px;
}

.entry-item-date {
  font-weight: 600;
  font-size: 0.9rem;
}

.entry-item-preview {
  color: var(--text-secondary);
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Detail View */
.detail-block {
  margin-bottom: var(--spacing-lg);
}

.detail-block h4 {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 4px;
}

.metric {
  text-align: center;
}

.metric .lbl {
  display: block;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.metric .val {
  font-weight: bold;
  font-size: 1.25rem;
}

/* Tags */
.tags-container {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  background: var(--border-color);
  padding: 4px 10px;
  border-radius: 16px;
  font-size: 0.75rem;
}

/* Stats View */
.huge-number {
  font-size: 3rem;
  font-weight: bold;
  text-align: center;
  color: var(--accent-color);
}

.chart-container {
  width: 100%;
  height: 200px;
  margin-top: var(--spacing-md);
}

/* Navigation */
#bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  justify-content: space-around;
  background-color: var(--surface-color);
  border-top: 1px solid var(--border-color);
  padding: 12px 0;
  z-index: 100;
}

.nav-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  color: var(--text-secondary);
  font-size: 1.2rem;
}

.nav-btn span {
  font-size: 0.65rem;
  margin-top: 4px;
}

.nav-btn.active {
  color: var(--accent-color);
}

/* Utilities */
.msg-error {
  color: var(--danger-color);
  font-size: 0.875rem;
  margin-top: 8px;
  text-align: center;
}

@media (min-width: 768px) {
  body {
    align-items: center;
    justify-content: center;
  }

  .app-container {
    max-width: 1000px;
    height: 94vh;
    margin-top: 0;
    border-radius: var(--radius);
    display: grid;
    grid-template-columns: 220px 1fr;
    grid-template-rows: auto 1fr;
    overflow: hidden;
  }

  header {
    grid-column: 2;
    grid-row: 1;
    border-left: 1px solid var(--border-color);
  }

  #main-content {
    grid-column: 2;
    grid-row: 2;
    border-left: 1px solid var(--border-color);
  }

  #bottom-nav {
    position: relative;
    grid-column: 1;
    grid-row: 1 / 3;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    padding-top: var(--spacing-lg);
    border-top: none;
    background-color: var(--surface-color);
  }

  .nav-btn {
    flex-direction: row;
    gap: 16px;
    padding: 16px 24px;
    justify-content: flex-start;
  }

  .nav-btn span {
    font-size: 1.1rem;
    margin-top: 0;
  }

  .view {
    padding: 40px 10%;
  }
}