/**
 * RoofPitchCalculator.co.uk — Ultra-Responsive, Ergonomic & Hardened CSS
 * Version: 5.0.0 Pro Suite (All-Device Optimized: 320px Mobile to 4K Ultrawide)
 */

:root {
  --rpc-blue-600: #2563eb;
  --rpc-blue-700: #1d4ed8;
  --rpc-blue-800: #1e40af;
  --rpc-blue-500: #3b82f6;
  --rpc-blue-50: #eff6ff;
  --rpc-slate-950: #020617;
  --rpc-slate-900: #0f172a;
  --rpc-slate-800: #1e293b;
  --rpc-slate-700: #334155;
  --rpc-slate-600: #475569;
  --rpc-slate-500: #64748b;
  --rpc-slate-400: #94a3b8;
  --rpc-slate-300: #cbd5e1;
  --rpc-slate-200: #e2e8f0;
  --rpc-slate-100: #f1f5f9;
  --rpc-slate-50: #f8fafc;
  --rpc-emerald-600: #059669;
  --rpc-emerald-50: #ecfdf5;
  --rpc-amber-600: #d97706;
  --rpc-amber-50: #fffbeb;
  --rpc-red-600: #dc2626;
  --rpc-red-50: #fef2f2;
  --rpc-shadow-card: 0 20px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
  --rpc-shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --rpc-shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08);
  --rpc-radius-xl: 20px;
  --rpc-radius-lg: 14px;
  --rpc-radius-md: 10px;
}

/* Master Calculator Card */
.roofpitch-calc-container {
  background: #ffffff;
  border: 1px solid var(--rpc-slate-200);
  border-radius: var(--rpc-radius-xl);
  box-shadow: var(--rpc-shadow-card);
  margin: 1.5rem 0 3rem 0;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--rpc-slate-800);
  transition: box-shadow 0.2s ease;
}

/* Quick Project Presets Bar - Fully Wrapping & Zero Cutoff */
.project-presets-bar {
  background: var(--rpc-slate-100);
  border-bottom: 1px solid var(--rpc-slate-200);
  padding: 0.85rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

@media (max-width: 640px) {
  .project-presets-bar {
    padding: 0.65rem 0.85rem;
    gap: 0.4rem;
  }
}

.preset-bar-title {
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--rpc-slate-500);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  white-space: nowrap;
  margin-right: 0.2rem;
}

.project-preset-chip {
  background: #ffffff;
  border: 1.5px solid var(--rpc-slate-300);
  border-radius: 9999px;
  padding: 0.45rem 0.95rem;
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--rpc-slate-700);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  box-shadow: var(--rpc-shadow-sm);
  user-select: none;
  touch-action: manipulation;
  min-height: 38px;
}

.project-preset-chip:hover {
  background: var(--rpc-blue-50);
  border-color: var(--rpc-blue-600);
  color: var(--rpc-blue-600);
  transform: translateY(-1px);
}

.project-preset-chip:active {
  transform: scale(0.96);
}

.project-preset-chip.active {
  background: var(--rpc-blue-600);
  border-color: var(--rpc-blue-600);
  color: #ffffff;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.35);
}

/* Header */
.calc-header-modern {
  padding: 1.25rem 1.75rem;
  border-bottom: 1px solid var(--rpc-slate-200);
  background: #ffffff;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

@media (max-width: 640px) {
  .calc-header-modern {
    padding: 1rem;
  }
}

.calc-title-group {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.calc-title-main {
  margin: 0;
  font-size: clamp(1.15rem, 2.5vw, 1.4rem);
  font-weight: 800;
  color: var(--rpc-slate-900);
  display: flex;
  align-items: center;
  gap: 0.55rem;
  letter-spacing: -0.02em;
}

.calc-title-main svg {
  color: var(--rpc-blue-600);
  flex-shrink: 0;
}

.calc-subtitle-main {
  font-size: clamp(0.75rem, 2vw, 0.8125rem);
  color: var(--rpc-slate-500);
  margin: 0;
  font-weight: 500;
}

.unit-selector-wrapper {
  display: inline-flex;
  align-items: center;
  background: var(--rpc-slate-50);
  border: 1.5px solid var(--rpc-slate-300);
  border-radius: var(--rpc-radius-md);
  padding: 0.35rem 0.65rem 0.35rem 0.85rem;
  box-shadow: var(--rpc-shadow-sm);
  min-height: 40px;
}

.unit-selector-wrapper label {
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--rpc-slate-500);
  text-transform: uppercase;
  margin-right: 0.4rem;
}

.calc-unit-select {
  border: none;
  background: transparent;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-slate-800);
  cursor: pointer;
  outline: none;
}

/* Nav Tabs - 4 Columns on Desktop, 2x2 Grid on Mobile */
.calc-nav-segmented {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  background: var(--rpc-slate-100);
  padding: 0.35rem;
  border-bottom: 1px solid var(--rpc-slate-200);
  gap: 0.35rem;
}

@media (max-width: 600px) {
  .calc-nav-segmented {
    grid-template-columns: repeat(2, 1fr);
  }
}

.calc-tab-btn {
  padding: 0.75rem 0.5rem;
  background: transparent;
  border: none;
  border-radius: var(--rpc-radius-md);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-slate-600);
  cursor: pointer;
  transition: all 0.15s ease;
  text-align: center;
  white-space: nowrap;
  touch-action: manipulation;
  min-height: 42px;
}

.calc-tab-btn:hover {
  color: var(--rpc-slate-900);
  background: rgba(255, 255, 255, 0.7);
}

.calc-tab-btn.active {
  background: #ffffff;
  color: var(--rpc-blue-600);
  box-shadow: var(--rpc-shadow-sm);
}

/* Grid Layout */
.calc-body-grid {
  display: grid;
  grid-template-columns: 1fr 1.25fr;
  gap: 2rem;
  padding: 1.75rem;
}

@media (max-width: 1024px) {
  .calc-body-grid {
    grid-template-columns: 1fr;
    gap: 1.75rem;
    padding: 1.25rem;
  }
}

@media (max-width: 480px) {
  .calc-body-grid {
    padding: 0.85rem;
    gap: 1.25rem;
  }
}

/* Inputs & Ergonomic Steppers */
.calc-inputs-pane {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.calc-tab-pane {
  display: none;
  flex-direction: column;
  gap: 1.15rem;
}

.calc-tab-pane.active {
  display: flex;
}

.calc-input-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.calc-label {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-slate-700);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.25rem;
}

.calc-input-help {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--rpc-slate-500);
}

.calc-input-wrap-stepper {
  display: flex;
  align-items: center;
  position: relative;
}

.calc-input-wrap-stepper .calc-input {
  width: 100%;
  padding: 0.85rem 3.5rem 0.85rem 3.25rem;
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  font-weight: 700;
  color: var(--rpc-slate-900);
  background: var(--rpc-slate-50);
  border: 1.5px solid var(--rpc-slate-300);
  border-radius: var(--rpc-radius-md);
  text-align: center;
  font-family: ui-monospace, SFMono-Regular, monospace;
  min-height: 48px;
}

.calc-input-wrap-stepper .calc-input:focus {
  outline: none;
  background: #ffffff;
  border-color: var(--rpc-blue-600);
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.15);
}

.calc-input-wrap-stepper .calc-input.calc-input-invalid {
  border-color: var(--rpc-red-500, #ef4444);
  background: #fff5f5;
  color: #b91c1c;
  box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.18);
}

.calc-field-error-msg {
  font-size: 0.75rem;
  font-weight: 700;
  color: #dc2626;
  margin-top: 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.btn-stepper {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 38px;
  height: 38px;
  background: #ffffff;
  border: 1.5px solid var(--rpc-slate-300);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--rpc-slate-700);
  cursor: pointer;
  z-index: 2;
  transition: all 0.12s ease;
  user-select: none;
  touch-action: manipulation;
  box-shadow: var(--rpc-shadow-sm);
}

.btn-stepper:hover {
  background: var(--rpc-blue-50);
  border-color: var(--rpc-blue-600);
  color: var(--rpc-blue-600);
}

.btn-stepper:active {
  transform: translateY(-50%) scale(0.92);
}

.btn-stepper.minus { left: 5px; }
.btn-stepper.plus { right: 54px; }

.calc-input-wrap-stepper .input-suffix {
  position: absolute;
  right: 14px;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-slate-500);
  pointer-events: none;
}

/* Range Slider Control */
.calc-slider-wrap {
  margin-top: 0.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.calc-range-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 10px;
  border-radius: 5px;
  background: var(--rpc-slate-200);
  outline: none;
  cursor: pointer;
  touch-action: manipulation;
}

.calc-range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--rpc-blue-600);
  border: 3px solid #ffffff;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
  cursor: grab;
  transition: transform 0.1s ease;
}

.calc-range-slider::-webkit-slider-thumb:active {
  cursor: grabbing;
  transform: scale(1.15);
}

.slider-ticks {
  display: flex;
  justify-content: space-between;
  font-size: 0.6875rem;
  color: var(--rpc-slate-500);
  font-weight: 700;
}

/* Plain English Explainer Card */
.calc-plain-english-card {
  background: #f0fdf4;
  border: 1.5px solid #bbf7d0;
  border-radius: var(--rpc-radius-md);
  padding: 1rem 1.25rem;
  font-size: 0.875rem;
  line-height: 1.6;
  color: #166534;
  box-shadow: var(--rpc-shadow-sm);
}

.plain-english-title {
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #15803d;
  margin-bottom: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* Material Compatibility List */
.calc-material-compat-section {
  background: #ffffff;
  border: 1px solid var(--rpc-slate-200);
  border-radius: var(--rpc-radius-md);
  padding: 1rem;
}

.material-compat-title {
  font-size: 0.8125rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--rpc-slate-800);
  margin-bottom: 0.65rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.material-compat-list {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  max-height: 200px;
  overflow-y: auto;
  padding-right: 0.3rem;
}

.material-compat-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  font-size: 0.8125rem;
  border: 1px solid transparent;
  gap: 0.5rem;
}

.material-compat-row.status-green { background: var(--rpc-emerald-50); border-color: #a7f3d0; }
.material-compat-row.status-amber { background: var(--rpc-amber-50); border-color: #fde68a; }
.material-compat-row.status-red { background: var(--rpc-red-50); border-color: #fecaca; }

.mat-info {
  display: flex;
  flex-direction: column;
}

.mat-name {
  font-weight: 700;
  color: var(--rpc-slate-900);
}

.mat-standard {
  font-size: 0.6875rem;
  color: var(--rpc-slate-500);
}

.mat-status-chip {
  font-size: 0.6875rem;
  font-weight: 800;
  text-transform: uppercase;
  padding: 0.25rem 0.55rem;
  border-radius: 4px;
  white-space: nowrap;
  flex-shrink: 0;
}

.mat-status-chip.compatible { background: #d1fae5; color: #065f46; }
.mat-status-chip.conditional { background: #fef3c7; color: #92400e; }
.mat-status-chip.prohibited { background: #fee2e2; color: #991b1b; }

/* Visual Results Column */
.calc-visual-results-pane {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Primary Metric Hero Card - Fluid & Responsive */
.calc-results-hero-modern {
  display: grid;
  grid-template-columns: 1.3fr 1fr 1fr;
  gap: 0.75rem;
  background: linear-gradient(135deg, var(--rpc-slate-950) 0%, var(--rpc-slate-900) 50%, var(--rpc-slate-800) 100%);
  color: #ffffff;
  border-radius: var(--rpc-radius-lg);
  padding: 1.35rem 1.6rem;
  box-shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.2);
}

@media (max-width: 600px) {
  .calc-results-hero-modern {
    grid-template-columns: 1fr;
    gap: 1rem;
    padding: 1.15rem;
  }
}

.result-card-hero {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.result-lbl-hero {
  font-size: 0.6875rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--rpc-slate-400);
}

.result-val-angle {
  font-size: clamp(1.8rem, 4vw, 2.3rem);
  font-weight: 900;
  color: #60a5fa;
  font-family: ui-monospace, SFMono-Regular, monospace;
  line-height: 1.05;
  letter-spacing: -0.02em;
}

.result-val-sub-white {
  font-size: clamp(1.1rem, 2.5vw, 1.3rem);
  font-weight: 800;
  color: #ffffff;
  font-family: ui-monospace, SFMono-Regular, monospace;
  line-height: 1.2;
}

/* Architectural Diagram Box */
.calc-diagram-box {
  background: #ffffff;
  border: 1.5px solid var(--rpc-slate-200);
  border-radius: var(--rpc-radius-lg);
  overflow: hidden;
  position: relative;
}

.diagram-canvas-wrapper {
  display: flex;
  flex-direction: column;
  width: 100%;
}

.diagram-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.6rem 0.85rem;
  background: var(--rpc-slate-50);
  border-bottom: 1px solid var(--rpc-slate-200);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.diagram-type-toggle {
  display: flex;
  gap: 0.35rem;
}

.btn-diag-toggle {
  background: #ffffff;
  border: 1px solid var(--rpc-slate-300);
  border-radius: 6px;
  padding: 0.3rem 0.65rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--rpc-slate-700);
  cursor: pointer;
  transition: all 0.12s ease;
  touch-action: manipulation;
}

.btn-diag-toggle.active {
  background: var(--rpc-blue-600);
  border-color: var(--rpc-blue-600);
  color: #ffffff;
}

.diagram-metric-pill {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--rpc-slate-700);
  background: #ffffff;
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  border: 1px solid var(--rpc-slate-200);
}

.roof-diagram-svg {
  width: 100%;
  height: auto;
  display: block;
  background: radial-gradient(circle at center, #f8fafc 20%, #ffffff 100%);
}

/* Secondary Metrics Grid */
.calc-secondary-results {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.65rem;
  background: var(--rpc-slate-50);
  border: 1px solid var(--rpc-slate-200);
  border-radius: var(--rpc-radius-md);
  padding: 1.15rem;
}

@media (max-width: 500px) {
  .calc-secondary-results {
    grid-template-columns: 1fr;
  }
}

.sec-result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  padding: 0.4rem 0;
  border-bottom: 1px dashed var(--rpc-slate-200);
  gap: 0.5rem;
}

.sec-result-row:last-child,
.sec-result-row:nth-last-child(2) {
  border-bottom: none;
}

.sec-lbl {
  color: var(--rpc-slate-600);
  font-weight: 600;
}

.sec-val {
  font-weight: 800;
  color: var(--rpc-slate-900);
  font-family: ui-monospace, SFMono-Regular, monospace;
  text-align: right;
}

/* Action Bar */
.calc-action-bar {
  background: var(--rpc-slate-50);
  border-top: 1px solid var(--rpc-slate-200);
  padding: 1.15rem 1.75rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

@media (max-width: 640px) {
  .calc-action-bar {
    padding: 1rem;
    flex-direction: column;
    align-items: stretch;
  }
  .calc-action-group {
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
  }
}

.calc-action-group {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.btn-calc-action {
  background: #ffffff;
  border: 1.5px solid var(--rpc-slate-300);
  border-radius: var(--rpc-radius-md);
  padding: 0.55rem 1rem;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-slate-700);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  transition: all 0.15s ease;
  box-shadow: var(--rpc-shadow-sm);
  touch-action: manipulation;
  min-height: 42px;
}

.btn-calc-action:hover {
  background: var(--rpc-slate-100);
  color: var(--rpc-slate-900);
  transform: translateY(-1px);
}

.btn-calc-action.btn-accent {
  background: var(--rpc-blue-600);
  border-color: var(--rpc-blue-600);
  color: #ffffff;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
}

.btn-calc-action.btn-accent:hover {
  background: var(--rpc-blue-700);
}

/* Formula Transparency Accordion */
.calc-formula-accordion {
  border-top: 1px solid var(--rpc-slate-200);
  padding: 1.15rem 1.75rem;
  background: #ffffff;
}

.calc-formula-accordion summary {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--rpc-blue-600);
  cursor: pointer;
  user-select: none;
}

.formula-step-list {
  margin: 0.75rem 0 0 0;
  padding-left: 1.25rem;
  font-size: 0.875rem;
  color: var(--rpc-slate-700);
  line-height: 1.6;
  font-family: ui-monospace, SFMono-Regular, monospace;
}

/* Toast Notifications */
.calc-toast-notification {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--rpc-slate-950);
  color: #ffffff;
  padding: 0.85rem 1.4rem;
  border-radius: 10px;
  box-shadow: var(--rpc-shadow-card);
  font-size: 0.875rem;
  font-weight: 700;
  z-index: 9999;
  opacity: 0;
  transform: translateY(12px);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

@media (max-width: 600px) {
  .calc-toast-notification {
    bottom: 1.5rem;
    right: 1.5rem;
    left: 1.5rem;
    text-align: center;
    justify-content: center;
  }
}

.calc-toast-notification.show {
  opacity: 1;
  transform: translateY(0);
}