/*
 * styles.css — Custom styles for the Matrix Calculator
 * Theme variables drive dark/light mode without JS class toggling.
 */

/* ─── Google Font ─────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ─── CSS Variables ───────────────────────────────── */
:root {
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  /* Light theme defaults */
  --bg:        #f0f4ff;
  --surface:   #ffffff;
  --surface2:  #f8fafc;
  --border:    #e2e8f0;
  --text:      #0f172a;
  --text-muted:#64748b;
  --accent:    #6366f1;
  --accent-2:  #8b5cf6;
  --success:   #10b981;
  --danger:    #ef4444;
  --warning:   #f59e0b;

  /* Matrix cell */
  --cell-bg:      #ffffff;
  --cell-border:  #cbd5e1;
  --cell-focus:   #6366f1;
  --cell-highlight-row: #ede9fe;
  --cell-highlight-col: #dbeafe;
  --cell-highlight-result: #d1fae5;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow:    0 4px 16px rgba(0,0,0,.10), 0 2px 4px rgba(0,0,0,.06);
  --shadow-lg: 0 10px 30px rgba(0,0,0,.14), 0 4px 10px rgba(0,0,0,.08);

  --radius: 12px;
  --radius-sm: 8px;
  --radius-xs: 4px;
}

/* Dark theme */
html.dark {
  --bg:        #0d0f1a;
  --surface:   #161828;
  --surface2:  #1e2135;
  --border:    #2a2d45;
  --text:      #e2e8f0;
  --text-muted:#8892a4;
  --accent:    #818cf8;
  --accent-2:  #a78bfa;
  --success:   #34d399;
  --danger:    #f87171;
  --warning:   #fbbf24;

  --cell-bg:      #1e2135;
  --cell-border:  #2e3250;
  --cell-focus:   #818cf8;
  --cell-highlight-row: #2d2458;
  --cell-highlight-col: #1a3a5c;
  --cell-highlight-result: #14402e;

  --shadow-sm: 0 1px 3px rgba(0,0,0,.3);
  --shadow:    0 4px 16px rgba(0,0,0,.4);
  --shadow-lg: 0 10px 30px rgba(0,0,0,.5);
}

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

html { font-family: var(--font-sans); scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background .3s, color .3s;
  font-size: 15px;
  line-height: 1.6;
}

/* ─── Layout ──────────────────────────────────────── */
.app-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

.main-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 900px) {
  .main-grid {
    grid-template-columns: 1fr;
  }
  .op-panel { order: -1; }
}

/* ─── Card / Surface ────────────────────────────────  */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.25rem;
  transition: background .3s, border-color .3s, box-shadow .3s;
}

.card-title {
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: .02em;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: .5rem;
  color: var(--text);
}

/* ─── Header ──────────────────────────────────────── */
.app-header {
  padding: 1.25rem 0 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -.03em;
}

.header-actions { display: flex; gap: .6rem; align-items: center; }

/* ─── Matrix Grid ─────────────────────────────────── */
.matrix-wrapper {
  overflow-x: auto;
  overflow-y: auto;
  max-height: 480px;
  border-radius: var(--radius-sm);
  /* Custom scrollbar */
  scrollbar-width: thin;
  scrollbar-color: var(--accent) transparent;
}
.matrix-wrapper::-webkit-scrollbar { width: 6px; height: 6px; }
.matrix-wrapper::-webkit-scrollbar-track { background: transparent; }
.matrix-wrapper::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }

.matrix-grid {
  display: inline-grid;
  gap: 3px;
  padding: 4px;
  position: relative;
}

/* ─── Matrix Cell ─────────────────────────────────── */
.matrix-cell {
  width: 54px;
  height: 40px;
  background: var(--cell-bg);
  border: 1.5px solid var(--cell-border);
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  text-align: center;
  color: var(--text);
  outline: none;
  transition: border-color .15s, background .15s, box-shadow .15s, transform .1s;
  padding: 0 4px;
  -moz-appearance: textfield;
}

.matrix-cell::-webkit-inner-spin-button,
.matrix-cell::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }

.matrix-cell:focus {
  border-color: var(--cell-focus);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--cell-focus) 25%, transparent);
  z-index: 1;
  position: relative;
  transform: scale(1.06);
}

.matrix-cell:hover:not(:focus) {
  border-color: var(--accent-2);
}

/* Highlighting states */
.matrix-cell.hl-row {
  background: var(--cell-highlight-row);
  border-color: var(--accent-2);
}
.matrix-cell.hl-col {
  background: var(--cell-highlight-col);
  border-color: #60a5fa;
}
.matrix-cell.hl-result {
  background: var(--cell-highlight-result);
  border-color: var(--success);
}
.matrix-cell.hl-active {
  background: color-mix(in srgb, var(--accent) 20%, var(--cell-bg));
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 30%, transparent);
}
.matrix-cell.hl-swap {
  background: color-mix(in srgb, var(--warning) 20%, var(--cell-bg));
  border-color: var(--warning);
}

/* Result cells (read-only) */
.matrix-cell.result-cell {
  background: var(--surface2);
  border-color: var(--success);
  cursor: default;
  font-weight: 700;
  color: var(--success);
}

/* ─── Brackets ────────────────────────────────────── */
.matrix-bracket-wrap {
  display: flex;
  align-items: center;
  gap: 4px;
}

.bracket {
  font-size: 3em;
  line-height: 1;
  color: var(--accent);
  font-weight: 200;
  user-select: none;
  flex-shrink: 0;
}

/* ─── Buttons ─────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .45rem .9rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: .825rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all .18s;
  white-space: nowrap;
  user-select: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  box-shadow: 0 2px 8px color-mix(in srgb, var(--accent) 40%, transparent);
}
.btn-primary:hover {
  filter: brightness(1.1);
  box-shadow: 0 4px 14px color-mix(in srgb, var(--accent) 50%, transparent);
  transform: translateY(-1px);
}
.btn-primary:active { transform: translateY(0); filter: brightness(.95); }

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border: 1.5px solid var(--border);
}
.btn-ghost:hover {
  background: var(--surface2);
  color: var(--text);
  border-color: var(--accent);
}

.btn-success {
  background: var(--success);
  color: #fff;
}
.btn-success:hover { filter: brightness(1.1); transform: translateY(-1px); }

.btn-danger {
  background: var(--danger);
  color: #fff;
}
.btn-danger:hover { filter: brightness(1.1); }

.btn-sm { padding: .3rem .65rem; font-size: .775rem; }
.btn-xs { padding: .2rem .5rem; font-size: .7rem; }
.btn-icon { padding: .45rem; border-radius: 50%; aspect-ratio: 1; }

/* Icon-only toggle button */
.theme-toggle {
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: 50%;
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all .2s;
  font-size: 1.1rem;
}
.theme-toggle:hover { border-color: var(--accent); background: var(--cell-highlight-row); }

/* ─── Operation Panel ─────────────────────────────── */
.op-panel {
  min-width: 180px;
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

.op-btn {
  width: 100%;
  padding: .6rem 1rem;
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: .85rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  text-align: left;
  transition: all .15s;
  display: flex;
  align-items: center;
  gap: .6rem;
}
.op-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--surface); }
.op-btn.active {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 2px 12px color-mix(in srgb, var(--accent) 40%, transparent);
}

.op-separator {
  height: 1px;
  background: var(--border);
  margin: .25rem 0;
}

/* ─── Result Panel ────────────────────────────────── */
.result-panel {
  margin-top: 1.5rem;
  animation: slideUp .35s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ─── Steps Panel ─────────────────────────────────── */
.steps-panel {
  margin-top: 1rem;
}

.step-card {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: .75rem 1rem;
  margin-bottom: .5rem;
  font-size: .875rem;
  animation: fadeIn .2s ease;
  position: relative;
}
.step-card.active-step {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 20%, transparent);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateX(-6px); }
  to   { opacity: 1; transform: translateX(0); }
}

.step-number {
  position: absolute;
  top: .6rem;
  right: .75rem;
  font-size: .7rem;
  font-weight: 700;
  color: var(--accent);
  opacity: .7;
}

.step-formula {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--text-muted);
  margin-top: .25rem;
}

.katex-display { margin: .3rem 0 !important; }

/* ─── Step Playback Controls ──────────────────────── */
.playback-controls {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-wrap: wrap;
  padding: .75rem 0;
}

.step-counter {
  font-size: .8rem;
  color: var(--text-muted);
  font-weight: 600;
  min-width: 70px;
}

.step-progress {
  flex: 1;
  min-width: 100px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}
.step-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 2px;
  transition: width .3s ease;
}

/* ─── History Panel ───────────────────────────────── */
.history-panel {
  max-height: 420px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--accent) transparent;
}

.history-item {
  display: flex;
  align-items: center;
  gap: .75rem;
  padding: .65rem .75rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all .15s;
  margin-bottom: .35rem;
}
.history-item:hover {
  background: var(--surface2);
  border-color: var(--border);
}
.history-item:active { background: var(--cell-highlight-row); }

.history-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
}
.history-meta { flex: 1; min-width: 0; }
.history-label {
  font-size: .825rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.history-time {
  font-size: .7rem;
  color: var(--text-muted);
}
.history-delete {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-muted);
  font-size: .9rem;
  padding: .2rem;
  border-radius: 4px;
  opacity: 0;
  transition: opacity .15s, color .15s;
}
.history-item:hover .history-delete { opacity: 1; }
.history-delete:hover { color: var(--danger); }

/* ─── Scalar input ────────────────────────────────── */
.scalar-input-wrap {
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: .5rem .75rem;
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  margin-top: .5rem;
}
.scalar-label { font-size: .85rem; font-weight: 600; color: var(--accent); white-space: nowrap; }
.scalar-input {
  width: 70px;
  padding: .3rem .5rem;
  background: var(--cell-bg);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-xs);
  font-family: var(--font-mono);
  font-size: .875rem;
  color: var(--text);
  text-align: center;
  outline: none;
  transition: border-color .15s;
  -moz-appearance: textfield;
}
.scalar-input:focus { border-color: var(--accent); }
.scalar-input::-webkit-inner-spin-button { -webkit-appearance: none; }

/* ─── Size Controls ───────────────────────────────── */
.size-controls {
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
  margin-bottom: .75rem;
}
.size-label { font-size: .8rem; color: var(--text-muted); font-weight: 500; }
.size-select {
  padding: .3rem .5rem;
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-xs);
  font-size: .825rem;
  color: var(--text);
  cursor: pointer;
  outline: none;
  font-family: var(--font-sans);
  transition: border-color .15s;
}
.size-select:focus { border-color: var(--accent); }

/* ─── Error / Toast ───────────────────────────────── */
.error-banner {
  background: color-mix(in srgb, var(--danger) 12%, var(--surface));
  border: 1.5px solid var(--danger);
  border-radius: var(--radius-sm);
  padding: .65rem 1rem;
  color: var(--danger);
  font-size: .875rem;
  font-weight: 500;
  margin-top: 1rem;
  animation: slideUp .25s ease;
}

.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: .5rem;
  pointer-events: none;
}

.toast {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: .65rem 1.1rem;
  box-shadow: var(--shadow-lg);
  font-size: .875rem;
  font-weight: 600;
  pointer-events: auto;
  animation: toastIn .3s ease;
  display: flex;
  align-items: center;
  gap: .5rem;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(12px) scale(.95); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

.toast.success { border-color: var(--success); color: var(--success); }
.toast.error   { border-color: var(--danger);  color: var(--danger);  }
.toast.info    { border-color: var(--accent);  color: var(--accent);  }

/* ─── Badge ───────────────────────────────────────── */
.badge {
  display: inline-flex;
  align-items: center;
  padding: .15rem .55rem;
  border-radius: 999px;
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .04em;
  background: color-mix(in srgb, var(--accent) 15%, transparent);
  color: var(--accent);
}

/* ─── Utility ─────────────────────────────────────── */
.hidden { display: none !important; }
.fade-in { animation: fadeIn .3s ease; }
.divider { height: 1px; background: var(--border); margin: 1rem 0; }
.mono { font-family: var(--font-mono); }
.text-accent { color: var(--accent); }
.text-muted  { color: var(--text-muted); }
.text-success{ color: var(--success); }
.text-danger { color: var(--danger); }

/* ─── Responsive ──────────────────────────────────── */
@media (max-width: 640px) {
  .app-header { flex-direction: column; align-items: flex-start; }
  .matrix-cell { width: 44px; height: 36px; font-size: 12px; }
  .bracket { font-size: 2.2em; }
}

/* ─── Print ───────────────────────────────────────── */
@media print {
  .app-header, .op-panel, .history-sidebar, .playback-controls,
  .btn, .size-controls, .matrix-cell:focus { box-shadow: none; }
  body { background: #fff; color: #000; }
}