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

:root {
  --c-bg: #f5f7fa;
  --c-surface: #ffffff;
  --c-border: #e2e8f0;
  --c-text: #1a202c;
  --c-text-secondary: #64748b;
  --c-primary: #2563eb;
  --c-primary-light: #dbeafe;
  --c-primary-dark: #1d4ed8;
  --c-success: #16a34a;
  --c-success-light: #dcfce7;
  --c-warning: #d97706;
  --c-warning-light: #fef3c7;
  --c-danger: #dc2626;
  --c-danger-light: #fee2e2;
  --c-low: #dc2626;
  --c-medium: #d97706;
  --c-high: #16a34a;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 4px 12px rgba(0,0,0,0.1);
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  --transition: 0.2s ease;
}

html { font-size: 16px; }
body {
  font-family: var(--font);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.6;
  min-height: 100vh;
}

/* ── Layout ──────────────────────────────────────────────────────── */
.app-header {
  background: var(--c-surface);
  border-bottom: 1px solid var(--c-border);
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}
.app-header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--c-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.app-header h1 .icon { font-size: 1.4rem; }
.header-actions { display: flex; gap: 0.5rem; }

.app-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* ── Stepper ─────────────────────────────────────────────────────── */
.stepper {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 2rem;
  gap: 0;
  flex-wrap: wrap;
}
.stepper-step {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius);
  transition: background var(--transition);
  white-space: nowrap;
}
.stepper-step:hover { background: var(--c-primary-light); }
.stepper-step.active .stepper-num {
  background: var(--c-primary);
  color: #fff;
}
.stepper-step.completed .stepper-num {
  background: var(--c-success);
  color: #fff;
}
.stepper-step.skipped { opacity: 0.4; pointer-events: none; }
.stepper-num {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--c-border);
  color: var(--c-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 600;
  flex-shrink: 0;
}
.stepper-label {
  font-size: 0.8rem;
  color: var(--c-text-secondary);
  font-weight: 500;
}
.stepper-step.active .stepper-label { color: var(--c-primary); font-weight: 600; }
.stepper-step.completed .stepper-label { color: var(--c-success); }
.stepper-connector {
  width: 24px;
  height: 2px;
  background: var(--c-border);
  flex-shrink: 0;
}
.stepper-connector.completed { background: var(--c-success); }

/* ── Card ────────────────────────────────────────────────────────── */
.card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem;
  margin-bottom: 1.5rem;
}
.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}
.card-subtitle {
  color: var(--c-text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
}

/* ── Form Elements ───────────────────────────────────────────────── */
.form-group {
  margin-bottom: 1.25rem;
}
.form-group:last-child { margin-bottom: 0; }
.form-label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.35rem;
  color: var(--c-text);
}
.form-label .optional {
  font-weight: 400;
  color: var(--c-text-secondary);
  font-size: 0.8rem;
}
.form-help {
  font-size: 0.8rem;
  color: var(--c-text-secondary);
  margin-top: 0.25rem;
}

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: var(--font);
  transition: border-color var(--transition), box-shadow var(--transition);
  background: #fff;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px var(--c-primary-light);
}
textarea { resize: vertical; min-height: 80px; }

/* Checkbox / multi-select list */
.checkbox-group { display: flex; flex-direction: column; gap: 0.5rem; }
.checkbox-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}
.checkbox-item:hover { background: var(--c-primary-light); border-color: var(--c-primary); }
.checkbox-item.selected { background: var(--c-primary-light); border-color: var(--c-primary); }
.checkbox-item input[type="checkbox"] {
  width: auto;
  accent-color: var(--c-primary);
}
.checkbox-item label { cursor: pointer; font-size: 0.9rem; flex: 1; }

/* Radio group */
.radio-group { display: flex; flex-direction: column; gap: 0.5rem; }
.radio-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}
.radio-item:hover { background: var(--c-primary-light); border-color: var(--c-primary); }
.radio-item.selected { background: var(--c-primary-light); border-color: var(--c-primary); }
.radio-item input[type="radio"] { width: auto; accent-color: var(--c-primary); }
.radio-item label { cursor: pointer; font-size: 0.9rem; flex: 1; }

/* Slider */
.slider-container {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.slider-container input[type="range"] {
  flex: 1;
  accent-color: var(--c-primary);
}
.slider-value {
  font-weight: 600;
  font-size: 0.95rem;
  min-width: 3rem;
  text-align: right;
}

/* ── Buttons ─────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1.2rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}
.btn-primary {
  background: var(--c-primary);
  color: #fff;
}
.btn-primary:hover { background: var(--c-primary-dark); }
.btn-secondary {
  background: var(--c-surface);
  color: var(--c-text);
  border-color: var(--c-border);
}
.btn-secondary:hover { background: var(--c-bg); }
.btn-ghost {
  background: transparent;
  color: var(--c-primary);
}
.btn-ghost:hover { background: var(--c-primary-light); }
.btn-sm { padding: 0.4rem 0.8rem; font-size: 0.8rem; }
.btn-success { background: var(--c-success); color: #fff; }
.btn-success:hover { background: #15803d; }

.btn-group {
  display: flex;
  gap: 0.75rem;
  margin-top: 1.5rem;
}
.btn-group-right { justify-content: flex-end; }
.btn-group-between { justify-content: space-between; }

/* ── Scenario Toggle ─────────────────────────────────────────────── */
.scenario-toggle {
  display: flex;
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  overflow: hidden;
  width: fit-content;
  margin: 0 auto 1.5rem;
}
.scenario-btn {
  padding: 0.5rem 1rem;
  border: none;
  background: none;
  font-size: 0.85rem;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  color: var(--c-text-secondary);
  transition: all var(--transition);
  border-right: 1px solid var(--c-border);
}
.scenario-btn:last-child { border-right: none; }
.scenario-btn:hover { background: var(--c-primary-light); color: var(--c-primary); }
.scenario-btn.active {
  background: var(--c-primary);
  color: #fff;
}

/* ── Tabs ────────────────────────────────────────────────────────── */
.tabs {
  display: flex;
  border-bottom: 2px solid var(--c-border);
  margin-bottom: 1.5rem;
  gap: 0;
}
.tab-btn {
  padding: 0.75rem 1.25rem;
  border: none;
  background: none;
  font-size: 0.9rem;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  color: var(--c-text-secondary);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all var(--transition);
}
.tab-btn:hover { color: var(--c-primary); }
.tab-btn.active {
  color: var(--c-primary);
  border-bottom-color: var(--c-primary);
}

/* ── Tooltip ─────────────────────────────────────────────────────── */
.tooltip-trigger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--c-border);
  color: var(--c-text-secondary);
  font-size: 0.7rem;
  font-weight: 700;
  cursor: help;
  margin-left: 0.35rem;
  position: relative;
  vertical-align: middle;
}
.tooltip-trigger:hover .tooltip-content {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}
.tooltip-content {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  background: var(--c-text);
  color: #fff;
  padding: 0.6rem 0.8rem;
  border-radius: var(--radius);
  font-size: 0.78rem;
  font-weight: 400;
  line-height: 1.5;
  width: 280px;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  pointer-events: none;
}
.tooltip-content::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--c-text);
}

/* ── Result Elements ─────────────────────────────────────────────── */
.result-hero {
  text-align: center;
  padding: 1.5rem;
  background: linear-gradient(135deg, var(--c-primary-light), #ede9fe);
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
}
.result-hero .big-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--c-primary);
}
.result-hero .range-text {
  font-size: 0.9rem;
  color: var(--c-text-secondary);
  margin-top: 0.25rem;
}

.confidence-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 600;
}
.confidence-badge.high { background: var(--c-success-light); color: var(--c-success); }
.confidence-badge.medium { background: var(--c-warning-light); color: var(--c-warning); }
.confidence-badge.low { background: var(--c-danger-light); color: var(--c-danger); }

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
.breakdown-table th {
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 2px solid var(--c-border);
  font-weight: 600;
  color: var(--c-text-secondary);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.breakdown-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--c-border);
}
.breakdown-table tr:last-child td { border-bottom: none; }
.breakdown-table .num { text-align: right; font-variant-numeric: tabular-nums; }
.breakdown-table tfoot td {
  font-weight: 700;
  border-top: 2px solid var(--c-border);
  border-bottom: none;
}

/* Bar chart */
.bar-chart { margin: 1rem 0; }
.bar-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}
.bar-label {
  font-size: 0.85rem;
  font-weight: 500;
  min-width: 100px;
  text-align: right;
}
.bar-track {
  flex: 1;
  height: 24px;
  background: var(--c-bg);
  border-radius: 4px;
  overflow: hidden;
}
.bar-fill {
  height: 100%;
  border-radius: 4px;
  transition: width 0.5s ease;
  min-width: 2px;
}
.bar-fill.cloud { background: var(--c-primary); }
.bar-fill.onprem { background: #8b5cf6; }
.bar-fill.saas { background: #06b6d4; }
.bar-fill.training { background: #f59e0b; }
.bar-fill.inference { background: #10b981; }
.bar-fill.internal { background: #6366f1; }
.bar-value {
  font-size: 0.8rem;
  font-weight: 600;
  min-width: 80px;
  font-variant-numeric: tabular-nums;
}

.uncertainty-list {
  list-style: none;
  margin: 0.5rem 0;
}
.uncertainty-list li {
  padding: 0.35rem 0;
  font-size: 0.85rem;
  color: var(--c-text-secondary);
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}
.uncertainty-list li::before {
  content: '\26A0';
  flex-shrink: 0;
}

.actions-list {
  list-style: none;
  counter-reset: action;
}
.actions-list li {
  padding: 0.5rem 0;
  font-size: 0.9rem;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  counter-increment: action;
}
.actions-list li::before {
  content: counter(action);
  flex-shrink: 0;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: var(--c-primary-light);
  color: var(--c-primary);
  font-size: 0.75rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Method & assumptions */
.assumptions-section { margin-bottom: 1.5rem; }
.assumptions-section h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--c-border);
}
.formula-box {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  font-family: var(--mono);
  font-size: 0.85rem;
  margin: 0.5rem 0;
  overflow-x: auto;
}
.disclaimer {
  background: var(--c-warning-light);
  border: 1px solid #fcd34d;
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  font-size: 0.85rem;
  color: #92400e;
  margin-top: 1rem;
}

/* Disclosure */
.disclosure-box {
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 1rem;
  white-space: pre-wrap;
}
.disclosure-box ul {
  margin: 0.5rem 0 0.5rem 1.5rem;
}
.disclosure-box li {
  margin-bottom: 0.25rem;
}

/* ── Warning/Info Boxes ──────────────────────────────────────────── */
.alert {
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}
.alert-warning {
  background: var(--c-warning-light);
  border: 1px solid #fcd34d;
  color: #92400e;
}
.alert-info {
  background: var(--c-primary-light);
  border: 1px solid #93c5fd;
  color: #1e40af;
}
.alert-success {
  background: var(--c-success-light);
  border: 1px solid #86efac;
  color: #166534;
}

/* ── Conditional sections ────────────────────────────────────────── */
.conditional { display: none; }
.conditional.visible { display: block; }

/* ── Copy feedback ───────────────────────────────────────────────── */
.copy-feedback {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--c-text);
  color: #fff;
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 600;
  opacity: 0;
  transition: all 0.3s ease;
  pointer-events: none;
  z-index: 9999;
}
.copy-feedback.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ── Inline number+unit ──────────────────────────────────────────── */
.input-with-unit {
  display: flex;
  align-items: center;
  gap: 0;
}
.input-with-unit input {
  border-top-right-radius: 0;
  border-bottom-right-radius: 0;
  flex: 1;
}
.input-unit {
  padding: 0.6rem 0.75rem;
  background: var(--c-bg);
  border: 1px solid var(--c-border);
  border-left: none;
  border-top-right-radius: var(--radius);
  border-bottom-right-radius: var(--radius);
  font-size: 0.85rem;
  color: var(--c-text-secondary);
  white-space: nowrap;
}

/* ── Print ───────────────────────────────────────────────────────── */
@media print {
  body { background: #fff; }
  .app-header, .stepper, .btn-group, .scenario-toggle,
  .tabs, .header-actions, .no-print { display: none !important; }
  .card { box-shadow: none; border: 1px solid #ccc; break-inside: avoid; }
  .tab-panel { display: block !important; }
  .result-hero { background: #f0f0f0 !important; -webkit-print-color-adjust: exact; }
}

/* ── Responsive ──────────────────────────────────────────────────── */
@media (max-width: 640px) {
  .app-container { padding: 1rem 0.75rem; }
  .card { padding: 1.25rem; }
  .stepper-label { display: none; }
  .stepper-step { padding: 0.4rem; }
  .btn-group { flex-direction: column; }
  .bar-label { min-width: 70px; font-size: 0.78rem; }
  .result-hero .big-number { font-size: 1.5rem; }
  .scenario-toggle { width: 100%; }
  .scenario-btn { flex: 1; }
  .tabs { overflow-x: auto; }
  .tab-btn { padding: 0.6rem 0.75rem; font-size: 0.8rem; white-space: nowrap; }
}

/* ── Footer ──────────────────────────────────────────────────────── */
.app-footer {
  text-align: center;
  padding: 1.5rem 1rem;
  margin-top: 1rem;
  border-top: 1px solid var(--c-border);
  font-size: 0.85rem;
  color: var(--c-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
}
.app-footer a {
  color: var(--c-primary);
  text-decoration: none;
  font-weight: 600;
}
.app-footer a:hover {
  text-decoration: underline;
}