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

/* ── Design tokens ── */
:root {
  --font: 'Inter', system-ui, sans-serif;

  /* Blue palette */
  --blue-50:  #eff6ff;
  --blue-100: #dbeafe;
  --blue-200: #bfdbfe;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --blue-700: #1d4ed8;
  --blue-800: #1e40af;

  /* Orange palette */
  --orange-50:  #fff7ed;
  --orange-100: #ffedd5;
  --orange-200: #fed7aa;
  --orange-400: #fb923c;
  --orange-500: #f97316;
  --orange-600: #ea580c;

  /* Semantic */
  --primary:       var(--blue-600);
  --primary-light: var(--blue-100);
  --primary-hover: var(--blue-700);
  --accent:        var(--orange-500);
  --accent-light:  var(--orange-100);

  /* Surfaces */
  --bg:           #f5f8ff;
  --panel:        #ffffff;
  --panel-raised: #ffffff;
  --border:       #e2e8f0;
  --border-subtle:#f0f4ff;

  /* Text */
  --text-primary:   #0f172a;
  --text-secondary: #475569;
  --text-muted:     #94a3b8;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(37,99,235,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 16px rgba(37,99,235,.08), 0 2px 6px rgba(0,0,0,.05);
  --shadow-lg: 0 8px 32px rgba(37,99,235,.12), 0 4px 12px rgba(0,0,0,.06);

  /* Shape */
  --radius:    10px;
  --radius-sm: 7px;
  --radius-xs: 5px;
}

/* ── DARK MODE ── */
[data-theme="dark"] {
  --bg:           #0a0f1e;
  --panel:        #111827;
  --panel-raised: #1a2235;
  --border:       #1e2d45;
  --border-subtle:#151f30;
  --text-primary:  #f1f5f9;
  --text-secondary:#94a3b8;
  --text-muted:    #4b6080;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.4);
  --shadow-md: 0 4px 16px rgba(0,0,0,.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,.6);
  --blue-50:  #0f1f3d;
  --blue-100: #1e3a6e;
  --orange-50:  #1c1208;
  --orange-100: #2c1a06;
}

html, body { height: 100%; font-family: var(--font); background: var(--bg); color: var(--text-primary); }
#app { display: flex; flex-direction: column; height: 100vh; overflow: hidden; }

/* ── TOP BAR ── */
.topbar {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 20px; height: 56px; flex-shrink: 0;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  z-index: 20;
  gap: 16px;
}
/* Thin gradient accent line at top */
.topbar::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--blue-600) 0%, #60a5fa 50%, var(--orange-500) 100%);
}

.topbar-brand {
  display: flex; align-items: center; gap: 9px;
  font-weight: 800; font-size: 1rem; white-space: nowrap;
  background: linear-gradient(135deg, var(--blue-600), var(--orange-500));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  justify-self: start;
}

/* Epoch counter — center column */
.topbar-center {
  display: flex; align-items: center; justify-content: center;
  pointer-events: none;
}
.epoch-counter {
  display: flex; align-items: baseline; gap: 6px;
  background: var(--blue-50); border: 1px solid var(--blue-200);
  border-radius: 20px; padding: 5px 18px; pointer-events: auto; white-space: nowrap;
}
.epoch-label {
  font-size: .65rem; font-weight: 600; color: var(--blue-600);
  text-transform: uppercase; letter-spacing: .07em;
}
.epoch-value {
  font-size: .92rem; font-weight: 800; color: var(--text-primary);
  min-width: 88px; text-align: center;
}

/* Right controls — always flush right */
.topbar-right {
  display: flex; align-items: center; gap: 8px;
  justify-self: end; white-space: nowrap;
}

/* Speed + divider */
.speed-control { display: flex; align-items: center; gap: 6px; }
.speed-label { font-size: .63rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: .06em; white-space: nowrap; }
.speed-slider { width: 70px; height: 4px; cursor: pointer; accent-color: var(--primary); }
.speed-val { font-size: .76rem; font-weight: 700; color: var(--text-secondary); min-width: 30px; }
.speed-val small { font-size: .6rem; color: var(--text-muted); }

/* Thin divider between speed and action buttons */
.topbar-divider {
  width: 1px; height: 22px; background: var(--border); flex-shrink: 0;
}

.topbar-buttons { display: flex; gap: 6px; }
.btn {
  display: inline-flex; align-items: center; gap: 5px; padding: 7px 14px;
  border: none; border-radius: var(--radius-sm); font-size: .8rem; font-weight: 700;
  cursor: pointer; transition: all .15s; white-space: nowrap; font-family: var(--font);
  letter-spacing: .01em;
}
.btn:active { transform: scale(.95); }

.btn-run {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-700));
  color: #fff;
  box-shadow: 0 2px 8px rgba(37,99,235,.35);
}
.btn-run:hover {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
  box-shadow: 0 4px 14px rgba(37,99,235,.45);
}
.btn-pause {
  background: var(--panel); color: var(--text-secondary);
  border: 1px solid var(--border);
}
.btn-pause:hover { background: var(--bg); border-color: var(--blue-200); color: var(--primary); }

.btn-reset {
  background: var(--orange-50); color: var(--orange-600);
  border: 1px solid var(--orange-200);
}
.btn-reset:hover { background: var(--orange-100); box-shadow: 0 2px 8px rgba(249,115,22,.2); }

.btn-icon {
  background: var(--bg); border: 1px solid var(--border);
  color: var(--text-muted); padding: 7px 10px;
}
.btn-icon:hover { background: var(--blue-50); border-color: var(--blue-200); color: var(--primary); }

.status-badge {
  font-size: .68rem; font-weight: 700; padding: 4px 11px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text-muted);
  white-space: nowrap; letter-spacing: .02em;
}
.status-badge.running {
  background: #dcfce7; border-color: #86efac; color: #15803d;
}
.status-badge.paused {
  background: var(--orange-50); border-color: var(--orange-200); color: var(--orange-600);
}

/* ── WORKSPACE ── */
.workspace { display: grid; grid-template-columns: 268px 1fr 288px; flex: 1; overflow: hidden; }

/* ── LEFT PANEL ── */
.panel-left {
  background: var(--panel); border-right: 1px solid var(--border);
  overflow-y: auto; padding: 16px 0; display: flex; flex-direction: column;
}
.panel-section { padding: 0 16px 20px; }
.panel-section + .panel-section { border-top: 1px solid var(--border-subtle); padding-top: 18px; }

.section-label {
  font-size: .65rem; font-weight: 800; text-transform: uppercase;
  letter-spacing: .09em; color: var(--text-muted); margin-bottom: 12px;
}

/* Algorithm selector */
.algo-select {
  width: 100%; padding: 9px 30px 9px 11px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: var(--bg);
  font-size: .82rem; font-weight: 600; color: var(--text-primary);
  cursor: pointer; outline: none; appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2.5'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 10px center;
  transition: border-color .15s, box-shadow .15s; font-family: var(--font);
}
.algo-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.12);
}

/* ── Param controls ── */
.param-box { display: flex; flex-direction: column; gap: 20px; }
.param-field { display: flex; flex-direction: column; gap: 6px; padding-bottom: 12px; border-bottom: 1px solid var(--border-subtle); }
.param-field:last-child { padding-bottom: 0; border-bottom: none; }
.param-header { display: flex; justify-content: space-between; align-items: center; }
.param-header label {
  font-size: .69rem; font-weight: 600; color: var(--text-primary); cursor: default;
}
.param-value-display {
  font-size: .68rem; font-weight: 700; color: var(--blue-600);
  background: var(--blue-50); border: 1px solid var(--blue-200);
  padding: 1px 7px; border-radius: 10px; min-width: 36px; text-align: center;
}

input[type="range"].param-slider {
  width: 100%; height: 4px; cursor: pointer;
  accent-color: var(--primary); border-radius: 2px; display: block;
}

.toggle-row { display: flex; align-items: center; justify-content: space-between; }
.toggle-row label { font-size: .69rem; font-weight: 600; color: var(--text-primary); }
input[type="checkbox"].toggle {
  width: 34px; height: 19px; appearance: none; background: #cbd5e1;
  border-radius: 10px; cursor: pointer; position: relative; transition: background .2s; flex-shrink: 0;
}
input[type="checkbox"].toggle::before {
  content: ''; position: absolute; top: 2.5px; left: 2.5px; width: 14px; height: 14px;
  border-radius: 50%; background: #fff; transition: left .2s; box-shadow: 0 1px 4px rgba(0,0,0,.2);
}
input[type="checkbox"].toggle:checked { background: var(--primary); }
input[type="checkbox"].toggle:checked::before { left: 17px; }

/* ── Tooltip icon ── */
.tip-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--blue-100); color: var(--blue-600);
  font-size: .62rem; font-weight: 800; font-style: italic; line-height: 1;
  cursor: default; flex-shrink: 0; user-select: none;
  transition: background .15s, color .15s, transform .15s;
  border: 1px solid var(--blue-200);
}
.tip-icon:hover, .tip-icon:focus {
  background: var(--primary); color: #fff;
  border-color: var(--primary); transform: scale(1.15); outline: none;
}

#tip-bubble {
  position: fixed; z-index: 9999; pointer-events: none;
  max-width: 230px; padding: 8px 12px;
  background: var(--text-primary); color: var(--panel);
  font-size: .73rem; line-height: 1.5; font-family: var(--font);
  border-radius: var(--radius-sm); box-shadow: var(--shadow-lg);
  opacity: 0; transition: opacity .12s;
  white-space: normal; word-break: break-word;
}
#tip-bubble.visible { opacity: 1; }

/* ── CENTER ── */
.panel-center {
  display: flex; align-items: center; justify-content: center;
  overflow: hidden; background: var(--bg); padding: 16px;
}
.simulation-root { width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; }
.simulation-root canvas {
  max-width: 100%; max-height: 100%; width: auto; height: auto;
  border-radius: var(--radius); box-shadow: var(--shadow-lg);
  display: block; background: #fff; aspect-ratio: 1;
  border: 1px solid var(--border);
}

/* ── RIGHT PANEL ── */
.panel-right {
  background: var(--panel); border-left: 1px solid var(--border);
  overflow-y: auto; padding: 16px 12px; display: flex; flex-direction: column; gap: 6px;
}
.metrics { display: flex; flex-direction: column; gap: 10px; margin-top: 6px; }

.metric-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-left: 3px solid var(--blue-200);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  transition: border-left-color .2s;
}
.metric-card:hover { border-left-color: var(--primary); }

.metric-card-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 4px; }
.metric-name-wrap { display: flex; align-items: center; gap: 5px; }
.metric-name {
  font-size: .62rem; font-weight: 800; text-transform: uppercase;
  letter-spacing: .07em; color: var(--text-muted);
}
.metric-last-value {
  font-size: .88rem; font-weight: 800; color: var(--text-primary);
}
.metric-last-value[data-metric-val="loss"],
.metric-last-value[data-metric-val="testLoss"] { color: #dc2626; }
.metric-last-value[data-metric-val="accuracy"],
.metric-last-value[data-metric-val="testAccuracy"],
.metric-last-value[data-metric-val="f1"],
.metric-last-value[data-metric-val="testF1"] { color: #16a34a; }
.metric-last-value[data-metric-val="mape"],
.metric-last-value[data-metric-val="testMAPE"] { color: var(--orange-500); }

.metric-card canvas { width: 100%; height: 52px; border-radius: 4px; display: block; }

/* ── Metric Train/Test toggle ── */
.metric-tab-row {
  display: flex; gap: 4px; margin-bottom: 8px;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 3px;
}
.metric-tab {
  flex: 1; padding: 5px 8px; border: none; border-radius: var(--radius-xs);
  background: transparent; font-size: .75rem; font-weight: 700;
  color: var(--text-muted); cursor: pointer; transition: all .15s;
  font-family: var(--font);
}
.metric-tab.active {
  background: var(--primary); color: #fff;
  box-shadow: 0 2px 6px rgba(37,99,235,.3);
}
.metrics-train-group,
.metrics-test-group { display: flex; flex-direction: column; gap: 10px; }

/* ── Task type tabs ── */
.task-tabs { display: flex; gap: 4px; margin-bottom: 10px; }
.task-tab {
  flex: 1; padding: 7px 8px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: var(--bg);
  font-size: .75rem; font-weight: 700; color: var(--text-muted);
  cursor: pointer; transition: all .15s; font-family: var(--font);
  text-transform: capitalize;
}
.task-tab:hover { border-color: var(--blue-200); color: var(--primary); background: var(--blue-50); }
.task-tab.active {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-700));
  border-color: var(--blue-700); color: #fff;
  box-shadow: 0 2px 8px rgba(37,99,235,.3);
}

/* ── Dataset chips ── */
.dataset-chips { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 4px; }
.dataset-chip {
  padding: 4px 10px; border: 1px solid var(--border);
  border-radius: 12px; background: var(--panel);
  font-size: .71rem; font-weight: 600; color: var(--text-secondary);
  cursor: pointer; transition: all .15s; font-family: var(--font); white-space: nowrap;
}
.dataset-chip:hover { border-color: var(--blue-200); color: var(--primary); background: var(--blue-50); }
.dataset-chip.active {
  background: var(--blue-50); border-color: var(--primary); color: var(--primary);
  font-weight: 700;
}

/* ── Select param ── */
.param-select {
  width: 100%; padding: 8px 28px 8px 10px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: var(--bg);
  font-size: .8rem; font-weight: 500; color: var(--text-primary);
  cursor: pointer; outline: none; appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2.5'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 8px center;
  transition: border-color .15s, box-shadow .15s; font-family: var(--font);
}
.param-select:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37,99,235,.1); }

/* ── Data source tabs ── */
.data-source-tabs {
  display: flex; gap: 4px; margin-bottom: 12px;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 3px;
}
.data-source-tab {
  flex: 1; padding: 5px 8px; border: none; border-radius: var(--radius-xs);
  background: transparent; font-size: .74rem; font-weight: 700; color: var(--text-muted);
  cursor: pointer; transition: all .15s; font-family: var(--font);
}
.data-source-tab.active {
  background: var(--primary); color: #fff;
  box-shadow: 0 2px 6px rgba(37,99,235,.28);
}
.data-section-content { display: flex; flex-direction: column; gap: 0; }

.data-always-section {
  margin-top: 14px; padding-top: 12px;
  border-top: 1px solid var(--border-subtle);
  display: flex; flex-direction: column; gap: 0;
}

/* ── Preset buttons ── */
.preset-row { display: flex; gap: 5px; margin-bottom: 10px; flex-wrap: wrap; }
.preset-btn {
  flex: 1; min-width: 60px; padding: 5px 8px;
  font-size: .7rem; font-weight: 700;
  border: 1px solid var(--border); border-radius: 20px; background: var(--panel);
  color: var(--text-secondary); cursor: pointer; white-space: nowrap;
  font-family: var(--font); transition: all .15s;
}
.preset-btn:hover {
  background: var(--orange-50); color: var(--orange-600);
  border-color: var(--orange-200); box-shadow: 0 2px 6px rgba(249,115,22,.15);
}

/* ── CSV import ── */
.csv-import-section { margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--border-subtle); }
.csv-import-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 6px; }
.csv-import-label { font-size: .68rem; font-weight: 700; color: var(--text-muted); text-transform: uppercase; letter-spacing: .06em; }
.csv-sample-link { font-size: .7rem; color: var(--primary); text-decoration: none; }
.csv-sample-link:hover { text-decoration: underline; }
.csv-status { font-size: .72rem; color: var(--text-muted); margin-bottom: 6px; }
.csv-status.loaded { color: #16a34a; font-weight: 600; }
.csv-file-row { display: flex; align-items: center; gap: 6px; }
.csv-file-input { display: none; }
.csv-choose-btn { padding: 5px 11px; font-size: .75rem; background: var(--bg); color: var(--text-secondary); border: 1px solid var(--border); border-radius: var(--radius-xs); }
.csv-choose-btn:hover { background: var(--blue-50); border-color: var(--blue-200); color: var(--primary); }
.csv-clear-btn { padding: 5px 11px; font-size: .75rem; background: var(--orange-50); color: var(--orange-600); border: 1px solid var(--orange-200); border-radius: var(--radius-xs); }
.csv-clear-btn:hover:not(:disabled) { background: var(--orange-100); }
.csv-clear-btn:disabled { opacity: .4; cursor: not-allowed; }
.csv-format-hint { font-size: .68rem; color: var(--text-muted); margin-top: 6px; line-height: 1.5; }
.csv-format-hint b { color: var(--text-secondary); }
.csv-format-hint code { font-family: monospace; font-size: .72rem; background: var(--surface-alt,#f1f5f9); padding: 0 3px; border-radius: 3px; color: var(--text-secondary); }
[data-theme="dark"] .csv-format-hint code { background: rgba(255,255,255,.07); }

/* ── Feature config (appears after CSV upload) ── */
.csv-feature-config {
  margin-top: 10px; padding: 8px 10px;
  background: var(--surface-alt, #f8fafc);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
}
[data-theme="dark"] .csv-feature-config { background: rgba(255,255,255,.03); }
.feat-config-title {
  font-size: .66rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .06em; color: var(--text-muted); margin-bottom: 7px;
}
.feat-checkboxes { display: flex; flex-wrap: wrap; gap: 5px 10px; margin-bottom: 8px; }
.feat-checkbox-label {
  display: flex; align-items: center; gap: 4px;
  font-size: .72rem; color: var(--text-secondary); cursor: pointer;
  padding: 2px 6px 2px 3px; border-radius: 4px;
  border: 1px solid var(--border-subtle);
  transition: background .15s, border-color .15s;
}
.feat-checkbox-label:has(input:checked) {
  background: rgba(59,130,246,.10); border-color: var(--primary);
  color: var(--primary); font-weight: 600;
}
.feat-checkbox-label input { cursor: pointer; accent-color: var(--primary); }
.feat-config-preview {
  font-size: .7rem; color: var(--text-muted); margin-bottom: 7px;
  font-style: italic; min-height: 14px;
}
.feat-apply-btn {
  width: 100%; padding: 5px; font-size: .75rem; font-weight: 600;
  background: var(--primary); color: #fff; border: none; border-radius: 5px;
  cursor: pointer; transition: opacity .15s;
}
.feat-apply-btn:hover { opacity: .88; }

/* ── Collapsible panels ── */
.panel-collapse-header {
  display: flex; align-items: center; justify-content: space-between;
  cursor: pointer; user-select: none; margin-bottom: 10px;
  padding: 6px 8px; border-radius: var(--radius-xs);
  transition: background .15s;
}
.panel-collapse-header:hover { background: var(--blue-50); }
.panel-collapse-header .section-label { margin-bottom: 0; }
.section-chevron { color: var(--text-muted); transition: transform .22s; flex-shrink: 0; }
.panel-collapse-header.collapsed .section-chevron { transform: rotate(-90deg); }
.panel-collapse-body { overflow: hidden; transition: max-height .3s ease; max-height: 1400px; }
.panel-collapse-body.collapsed { max-height: 0; }

/* ── Algo info panel ── */
.algo-info-header {
  display: flex; align-items: center; justify-content: space-between;
  cursor: pointer; user-select: none; padding: 8px;
  margin-top: 8px; border-radius: var(--radius-xs);
  border: 1px solid var(--border-subtle); background: var(--bg);
  transition: background .15s, border-color .15s;
}
.algo-info-header:hover { background: var(--blue-50); border-color: var(--blue-200); }
.algo-info-chevron { color: var(--text-muted); transition: transform .22s; flex-shrink: 0; }
.algo-info-header.collapsed .algo-info-chevron { transform: rotate(-90deg); }
.algo-info-body { overflow: hidden; transition: max-height .3s ease; max-height: 800px; }
.algo-info-body.collapsed { max-height: 0; }
.algo-info-tagline {
  font-size: .68rem; font-weight: 800; text-transform: uppercase; letter-spacing: .07em;
  color: var(--orange-500); margin: 10px 0 6px;
}
.algo-info-desc { font-size: .75rem; color: var(--text-secondary); line-height: 1.55; margin-bottom: 8px; }
.algo-info-insights { list-style: none; display: flex; flex-direction: column; gap: 5px; }
.algo-info-insights li {
  font-size: .71rem; color: var(--text-muted); line-height: 1.4;
  padding: 4px 8px 4px 20px; position: relative;
  background: var(--bg); border-radius: var(--radius-xs);
  border-left: 2px solid var(--blue-200);
}
.algo-info-insights li::before {
  content: "→"; position: absolute; left: 6px; color: var(--primary);
}

/* ── Scrollbars ── */
.panel-left::-webkit-scrollbar, .panel-right::-webkit-scrollbar { width: 3px; }
.panel-left::-webkit-scrollbar-thumb, .panel-right::-webkit-scrollbar-thumb {
  background: var(--blue-200); border-radius: 2px;
}
.panel-left::-webkit-scrollbar-track, .panel-right::-webkit-scrollbar-track { background: transparent; }

/* ── Responsive ── */
@media (max-width: 1100px) { .workspace { grid-template-columns: 248px 1fr 256px; } }
@media (max-width: 900px) {
  .topbar { grid-template-columns: auto 1fr; gap: 10px; }
  .topbar-center { justify-content: flex-end; }
  .topbar-right { display: none; } /* collapse on small screens */
}
@media (max-width: 860px) {
  #app { height: auto; overflow: auto; }
  .workspace { grid-template-columns: 1fr; }
  .topbar { grid-template-columns: 1fr; height: auto; padding: 10px 14px; gap: 8px; }
  .panel-center { min-height: 80vw; }
}