/* ==========================================================================
   PULSE — Expense Tracker (Premium Light Theme)
   Design tokens: soft lavender canvas, white cards, indigo → purple gradient
   ========================================================================== */

:root {
  /* Color — surfaces */
  --bg-canvas:      #f4f5fb;
  --bg-surface:     #ffffff;
  --bg-surface-alt: #f7f7fc;
  --bg-elevated:    #fbfaff;
  --border-subtle:  #eceafb;
  --border-strong:  #ded9f7;

  /* Color — brand */
  --indigo:         #4f46e5;
  --indigo-dark:    #4338ca;
  --purple:         #7c3aed;
  --gradient-brand: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
  --gradient-brand-hover: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  --accent-soft:    #eef0fd;

  /* Color — semantic */
  --income:         #0d9f6e;
  --income-soft:    #e7f9f1;
  --expense:        #e11d48;
  --expense-soft:   #fdeaee;

  /* Color — text */
  --text-primary:   #1c1934;
  --text-secondary: #6b7290;
  --text-tertiary:  #a3a8c3;

  /* Type */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

  /* Layout */
  --max-width: 1180px;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-pill: 999px;

  --shadow-xs: 0 1px 2px rgba(28, 25, 52, 0.04);
  --shadow-card: 0 1px 1px rgba(28, 25, 52, 0.03), 0 16px 32px -20px rgba(79, 70, 229, 0.22);
  --shadow-card-hover: 0 1px 1px rgba(28, 25, 52, 0.04), 0 22px 40px -18px rgba(79, 70, 229, 0.28);
  --shadow-btn: 0 10px 24px -10px rgba(79, 70, 229, 0.55);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ==========================================================================
   RESET
   ========================================================================== */

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

body {
  margin: 0;
  background: var(--bg-canvas);
  background-image:
    radial-gradient(circle at 12% -8%, rgba(99, 102, 241, 0.08), transparent 40%),
    radial-gradient(circle at 88% 6%, rgba(139, 92, 246, 0.07), transparent 38%);
  background-attachment: fixed;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "tnum" 1, "cv02" 1;
}

h1, h2, h3 { margin: 0; letter-spacing: -0.01em; }
p { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

:focus-visible {
  outline: 2px solid var(--indigo);
  outline-offset: 2px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--indigo);
  color: #fff;
  padding: 0.75rem 1.25rem;
  z-index: 1000;
  border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   NAVBAR
   ========================================================================== */

.navbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.navbar__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.15rem 1.5rem;
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.brand__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.1rem;
  height: 2.1rem;
  border-radius: var(--radius-sm);
  background: var(--gradient-brand);
  color: #fff;
  box-shadow: 0 6px 14px -6px rgba(79, 70, 229, 0.55);
}

.navbar__tagline {
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

/* ==========================================================================
   APP LAYOUT
   ========================================================================== */

.app {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.75rem 1.5rem 4rem;
}

.app-grid {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 1.5rem;
  align-items: start;
  margin-top: 1.5rem;
}

.panel {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.85rem;
  box-shadow: var(--shadow-card);
  animation: rise 0.5s var(--ease) backwards;
}

.panel h2 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 1.4rem;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   STAT CARDS
   ========================================================================== */

.stat-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 1.25rem;
}

.stat-card {
  position: relative;
  overflow: hidden;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.6rem;
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.25s ease, transform 0.25s ease;
  animation: rise 0.5s var(--ease) backwards;
}

.stat-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.stat-grid .stat-card:nth-child(1) { animation-delay: 0.02s; }
.stat-grid .stat-card:nth-child(2) { animation-delay: 0.08s; }
.stat-grid .stat-card:nth-child(3) { animation-delay: 0.14s; }
.stat-grid .stat-card:nth-child(4) { animation-delay: 0.2s; }

.stat-card__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.stat-card--income .stat-card__icon { background: var(--income-soft); color: var(--income); }
.stat-card--expense .stat-card__icon { background: var(--expense-soft); color: var(--expense); }
.stat-card--count .stat-card__icon { background: var(--accent-soft); color: var(--indigo); }

.stat-card__label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.stat-card__value {
  font-variant-numeric: tabular-nums;
  font-size: 1.65rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.stat-card--income .stat-card__value { color: var(--income); }
.stat-card--expense .stat-card__value { color: var(--expense); }

.stat-card--balance {
  background: linear-gradient(160deg, var(--bg-elevated), var(--bg-surface));
  padding: 1.85rem;
}

.stat-card--balance .stat-card__value {
  font-size: 2.5rem;
}

.stat-card--balance .stat-card__hint {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  margin-top: 0.4rem;
}

.stat-card__content { position: relative; z-index: 1; }

/* Signature element: soft rotating gradient glow behind the balance figure */
.pulse-ring {
  position: absolute;
  top: -70px;
  right: -70px;
  width: 220px;
  height: 220px;
  border-radius: 50%;
  background: conic-gradient(from 90deg, #6366f1, #8b5cf6, #6366f1);
  opacity: 0.16;
  filter: blur(34px);
  animation: pulse-spin 12s linear infinite;
}

@keyframes pulse-spin {
  to { transform: rotate(360deg); }
}

.stat-card--balance.is-negative .pulse-ring {
  background: conic-gradient(from 90deg, var(--expense), #8b5cf6, var(--expense));
}

/* ==========================================================================
   FORM CONTROLS — shared, consistent styling for inputs & dropdowns
   ========================================================================== */

.form-field {
  margin-bottom: 1.2rem;
}

.form-field label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.form-field input,
.form-field select {
  width: 100%;
  padding: 0.75rem 0.9rem;
  background: var(--bg-surface-alt);
  border: 1.5px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.95rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.form-field input::placeholder { color: var(--text-tertiary); }

.form-field input:focus,
.form-field select:focus {
  border-color: var(--indigo);
  background: #fff;
  box-shadow: 0 0 0 4px var(--accent-soft);
  outline: none;
}

.form-field select {
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%236b7290' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.85rem center;
  background-size: 16px;
  padding-right: 2.5rem;
  cursor: pointer;
}

.form-field select option {
  color: var(--text-primary);
  background: #fff;
}

.field-error {
  display: block;
  min-height: 1.1rem;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--expense);
  margin-top: 0.4rem;
}

.form-field.has-error input,
.form-field.has-error select {
  border-color: var(--expense);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

/* ==========================================================================
   ADD TRANSACTION — type toggle
   ========================================================================== */

.type-toggle {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: var(--bg-surface-alt);
  border: 1.5px solid var(--border-subtle);
  border-radius: var(--radius-pill);
  padding: 4px;
  margin-bottom: 1.6rem;
}

.type-toggle input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.type-toggle__option {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 0.6rem 0.5rem;
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: color 0.25s var(--ease);
}

.type-toggle__thumb {
  position: absolute;
  top: 4px;
  left: 4px;
  width: calc(50% - 4px);
  height: calc(100% - 8px);
  border-radius: var(--radius-pill);
  background: linear-gradient(135deg, #fb7185, var(--expense));
  box-shadow: 0 6px 14px -6px rgba(225, 29, 72, 0.45);
  transition: transform 0.3s var(--ease), background 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

#type-income:checked ~ .type-toggle__thumb {
  transform: translateX(100%);
  background: linear-gradient(135deg, #34d399, var(--income));
  box-shadow: 0 6px 14px -6px rgba(13, 159, 110, 0.45);
}

#type-expense:checked ~ .type-toggle__option--expense,
#type-income:checked ~ .type-toggle__option--income {
  color: #ffffff;
}

/* ==========================================================================
   BUTTONS — gradient, modern
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.85rem 1.4rem;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.15s var(--ease), box-shadow 0.2s ease, filter 0.2s ease;
}

.btn--primary {
  background: var(--gradient-brand);
  color: #fff;
  box-shadow: var(--shadow-btn);
}

.btn--primary:hover { filter: brightness(1.06); box-shadow: 0 14px 28px -10px rgba(79, 70, 229, 0.6); }
.btn--primary:active { transform: scale(0.98); }

.btn--block { width: 100%; margin-top: 0.5rem; }

/* ==========================================================================
   TRANSACTION HISTORY — header & controls
   ========================================================================== */

.history__header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.4rem;
}

.history__header h2 { margin-bottom: 0; }

.history__controls {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.search-field {
  position: relative;
  display: flex;
  align-items: center;
}

.search-field__icon {
  position: absolute;
  left: 0.85rem;
  color: var(--text-tertiary);
  pointer-events: none;
}

.search-field input {
  width: 230px;
  padding: 0.7rem 0.9rem 0.7rem 2.35rem;
  background: var(--bg-surface-alt);
  border: 1.5px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.9rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.search-field input::placeholder { color: var(--text-tertiary); }

.search-field input:focus {
  border-color: var(--indigo);
  background: #fff;
  box-shadow: 0 0 0 4px var(--accent-soft);
  outline: none;
}

.form-field--inline {
  margin-bottom: 0;
  min-width: 170px;
}

.form-field--inline select {
  padding: 0.7rem 2.5rem 0.7rem 0.9rem;
}

/* ==========================================================================
   TRANSACTION TABLE
   ========================================================================== */

.transaction-table {
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.transaction-table__head {
  display: grid;
  grid-template-columns: 2fr 1.1fr 1fr 1fr 2.75rem;
  gap: 0.75rem;
  align-items: center;
  padding: 0.85rem 1.1rem;
  background: var(--bg-surface-alt);
  border-bottom: 1px solid var(--border-subtle);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-tertiary);
}

.transaction-list {
  display: flex;
  flex-direction: column;
}

.transaction {
  display: grid;
  grid-template-columns: 2fr 1.1fr 1fr 1fr 2.75rem;
  gap: 0.75rem;
  align-items: center;
  padding: 0.95rem 1.1rem;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  animation: fade-in 0.35s var(--ease) backwards;
  transition: background 0.2s ease, opacity 0.25s ease;
}

.transaction:last-child { border-bottom: none; }

.transaction:hover {
  background: var(--bg-surface-alt);
}

@keyframes fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.transaction.is-removing {
  opacity: 0;
}

.transaction__col {
  display: flex;
  align-items: center;
  min-width: 0;
}

.transaction__col--desc {
  gap: 0.65rem;
}

.transaction__col--amount {
  justify-content: flex-end;
}

.transaction__col--action {
  justify-content: flex-end;
}

.transaction__dot {
  flex-shrink: 0;
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--indigo);
}

.transaction[data-type="income"] .transaction__dot { background: var(--income); }
.transaction[data-type="expense"] .transaction__dot { background: var(--expense); }

.transaction__description {
  font-weight: 600;
  font-size: 0.92rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.transaction__category {
  display: inline-block;
  font-size: 0.76rem;
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-pill);
  background: var(--accent-soft);
  color: var(--indigo-dark);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}

.transaction[data-type="income"] .transaction__category {
  background: var(--income-soft);
  color: var(--income);
}

.transaction__date {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.transaction__amount {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 0.95rem;
  white-space: nowrap;
}

.transaction[data-type="income"] .transaction__amount { color: var(--income); }
.transaction[data-type="expense"] .transaction__amount { color: var(--expense); }

.transaction__delete {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.1rem;
  height: 2.1rem;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-tertiary);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.transaction__delete:hover {
  background: var(--expense-soft);
  color: var(--expense);
}

/* ==========================================================================
   EMPTY STATE
   ========================================================================== */

.empty-state {
  text-align: center;
  padding: 3.25rem 1.5rem;
  color: var(--text-tertiary);
  animation: rise 0.4s var(--ease);
}

.empty-state__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 4rem;
  height: 4rem;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--indigo);
  margin-bottom: 1.1rem;
}

.empty-state__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.empty-state__hint {
  font-size: 0.88rem;
  max-width: 32ch;
  margin: 0 auto;
  color: var(--text-secondary);
}

/* ==========================================================================
   FOOTER
   ========================================================================== */

.site-footer {
  text-align: center;
  padding: 2rem 1.5rem;
  color: var(--text-tertiary);
  font-size: 0.82rem;
  border-top: 1px solid var(--border-subtle);
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */

@media (max-width: 1024px) {
  .stat-grid {
    grid-template-columns: 1fr 1fr;
  }
  .stat-card--balance {
    grid-column: span 2;
  }
  .app-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 780px) {
  .transaction-table__head {
    display: none;
  }

  .transaction {
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "desc action"
      "category amount"
      "date amount";
    row-gap: 0.4rem;
  }

  .transaction__col--desc { grid-area: desc; }
  .transaction__col--category { grid-area: category; }
  .transaction__col--date { grid-area: date; justify-content: flex-start; }
  .transaction__col--amount { grid-area: amount; align-items: flex-end; }
  .transaction__col--action { grid-area: action; }
}

@media (max-width: 640px) {
  .navbar__tagline { display: none; }

  .stat-grid {
    grid-template-columns: 1fr;
  }
  .stat-card--balance {
    grid-column: span 1;
  }

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

  .history__header {
    flex-direction: column;
    align-items: stretch;
  }

  .history__controls {
    flex-direction: column;
  }

  .search-field input {
    width: 100%;
  }
}