/* ============================================================
   IntelliTC Solutions — Shared Calculator Design Tokens
   ============================================================ */
:root {
  /* Type */
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);

  /* Spacing */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Fonts */
  --font-body: 'DM Sans', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
}

/* ============================================================
   Color — Light (default)
   ============================================================ */
:root, [data-theme="light"] {
  --color-bg:             #f7f6f2;
  --color-surface:        #ffffff;
  --color-surface-2:      #fbfbf9;
  --color-surface-offset: #f3f0ec;
  --color-border:         #d4d1ca;
  --color-divider:        #e6e4df;
  --color-text:           #28251d;
  --color-text-muted:     #7a7974;
  --color-text-faint:     #bab9b4;
  --color-text-inverse:   #f9f8f4;
  --color-primary:        #01696f;
  --color-primary-hover:  #0c4e54;
  --color-primary-surface: #e8f4f5;
  --color-error:          #a13544;
  --color-success:        #437a22;
  --color-warning:        #964219;

  /* Chart palette */
  --chart-1:          #20808D;
  --chart-2:          #A84B2F;
  --chart-3:          #1B474D;
  --chart-4:          #BCE2E7;
  --chart-5:          #944454;
  --chart-6:          #FFC553;
  --chart-7:          #848456;
  --chart-8:          #6E522B;
  --chart-1-light:    rgba(32, 128, 141, 0.12);
  --chart-2-light:    rgba(168, 75, 47, 0.12);

  --shadow-sm: 0 1px 2px rgba(40, 37, 29, 0.06);
  --shadow-md: 0 4px 12px rgba(40, 37, 29, 0.08);
  --shadow-lg: 0 12px 32px rgba(40, 37, 29, 0.12);
}

/* ============================================================
   Color — Dark
   ============================================================ */
[data-theme="dark"] {
  --color-bg:             #141312;
  --color-surface:        #1c1b19;
  --color-surface-2:      #201f1d;
  --color-surface-offset: #1d1c1a;
  --color-border:         #393836;
  --color-divider:        #2d2c2a;
  --color-text:           #cdccca;
  --color-text-muted:     #8a8985;
  --color-text-faint:     #5a5957;
  --color-text-inverse:   #2b2a28;
  --color-primary:        #4f98a3;
  --color-primary-hover:  #6bb0ba;
  --color-primary-surface: #1d2f32;
  --color-error:          #dd6974;
  --color-success:        #6daa45;
  --color-warning:        #bb653b;

  --chart-1:          #4f98a3;
  --chart-2:          #d18a6f;
  --chart-3:          #6bb0ba;
  --chart-4:          #3a5c62;
  --chart-5:          #c27888;
  --chart-6:          #e8af34;
  --chart-7:          #a8a86e;
  --chart-8:          #b08a5b;
  --chart-1-light:    rgba(79, 152, 163, 0.12);
  --chart-2-light:    rgba(209, 138, 111, 0.12);

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg:             #141312;
    --color-surface:        #1c1b19;
    --color-surface-2:      #201f1d;
    --color-surface-offset: #1d1c1a;
    --color-border:         #393836;
    --color-divider:        #2d2c2a;
    --color-text:           #cdccca;
    --color-text-muted:     #8a8985;
    --color-text-faint:     #5a5957;
    --color-text-inverse:   #2b2a28;
    --color-primary:        #4f98a3;
    --color-primary-hover:  #6bb0ba;
    --color-primary-surface: #1d2f32;
    --color-error:          #dd6974;
    --color-success:        #6daa45;
    --color-warning:        #bb653b;
    --chart-1:          #4f98a3;
    --chart-2:          #d18a6f;
    --chart-3:          #6bb0ba;
    --chart-4:          #3a5c62;
    --chart-5:          #c27888;
    --chart-6:          #e8af34;
    --chart-7:          #a8a86e;
    --chart-8:          #b08a5b;
    --chart-1-light:    rgba(79, 152, 163, 0.12);
    --chart-2-light:    rgba(209, 138, 111, 0.12);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.4);
  }
}

/* ============================================================
   Layout
   ============================================================ */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-divider);
  backdrop-filter: blur(12px);
}
.header-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-3) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.header-inner nav a { white-space: nowrap; }
@media(max-width:480px){
  .header-inner { padding: var(--space-3) var(--space-3); }
  .header-inner nav { gap: var(--space-2) !important; }
  .header-inner nav a { font-size: 11px !important; }
  .logo svg { width: 22px; height: 22px; }
  .logo-text { font-size: var(--text-sm) !important; }
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-text);
}
.logo svg { flex-shrink: 0; }
.logo-text {
  font-size: var(--text-lg);
  font-weight: 700;
  letter-spacing: -0.02em;
}
.logo-accent {
  color: var(--color-primary);
}

[data-theme-toggle] {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}
[data-theme-toggle]:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}

.main {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-8) var(--space-6);
}

/* ============================================================
   Panels
   ============================================================ */
.panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-sm);
}
.panel-title {
  font-size: var(--text-xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-2);
}
.panel-subtitle {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  margin-bottom: var(--space-6);
}

.hidden { display: none !important; }

/* ============================================================
   Inputs
   ============================================================ */
.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.field label {
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

input[type="text"], input[type="number"], select {
  height: 42px;
  padding: var(--space-2) var(--space-3);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums lining-nums;
  color: var(--color-text);
  width: 100%;
}
input:focus, select:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-surface);
  outline: none;
}

.input-with-unit {
  display: flex;
  align-items: center;
  gap: 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.input-with-unit:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-surface);
}
.input-with-unit input {
  border: none;
  background: transparent;
  height: 40px;
  flex: 1;
  min-width: 0;
  box-shadow: none !important;
}
.input-with-unit input:focus {
  box-shadow: none !important;
  border: none;
}
.unit {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  padding: 0 var(--space-2);
  flex-shrink: 0;
  font-family: var(--font-mono);
  user-select: none;
}

.divider {
  height: 1px;
  background: var(--color-divider);
  margin: var(--space-6) 0;
}

/* ============================================================
   Parameter Grid
   ============================================================ */
.params-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-8);
}
.param-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.param-group-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-divider);
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-md);
  white-space: nowrap;
  height: 42px;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}
.btn-primary:hover {
  background: var(--color-primary-hover);
}
.btn-ghost {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-border);
}
.btn-ghost:hover {
  background: var(--color-primary-surface);
}
.btn-run {
  width: 100%;
  max-width: 400px;
  margin: var(--space-8) auto 0;
  height: 48px;
  font-size: var(--text-base);
  border-radius: var(--radius-lg);
}
.btn-run.loading {
  opacity: 0.7;
  pointer-events: none;
}

/* ============================================================
   Results
   ============================================================ */
.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}
.results-header .panel-title { margin-bottom: 0; }

/* Home Button */
.btn-home {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 600;
  font-family: var(--font-body);
  color: var(--color-text-muted);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: color var(--transition-interactive), border-color var(--transition-interactive), background var(--transition-interactive);
  text-decoration: none;
  white-space: nowrap;
}
.btn-home:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: var(--color-primary-surface);
}
.btn-home svg {
  flex-shrink: 0;
}

/* Export Buttons */
.export-group {
  display: flex;
  gap: var(--space-2);
  align-items: center;
}
.btn-export {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 600;
  font-family: var(--font-body);
  color: var(--color-primary);
  background: var(--color-primary-surface);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-interactive), color var(--transition-interactive);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.btn-export:hover {
  background: var(--color-primary);
  color: #fff;
}
.btn-export svg {
  flex-shrink: 0;
}

/* KPI Cards */
.kpi-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}
.kpi-card {
  background: var(--color-bg);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.kpi-label {
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.kpi-value {
  font-size: var(--text-xl);
  font-weight: 700;
  font-variant-numeric: tabular-nums lining-nums;
  letter-spacing: -0.02em;
}
.kpi-delta {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}
.kpi-positive { color: var(--color-success); }
.kpi-negative { color: var(--color-error); }

/* Charts */
.chart-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 480px), 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}
.chart-card {
  background: var(--color-bg);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}
.chart-title {
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-1);
}
.chart-subtitle {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}
.chart-container {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 10;
}
.chart-container canvas {
  width: 100% !important;
  height: 100% !important;
}
.chart-container-bar {
  aspect-ratio: 16 / 9;
}

/* Assumptions */
.assumptions-card {
  background: var(--color-bg);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}
.assumptions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-3) var(--space-6);
  margin-top: var(--space-4);
}
.assumption-item {
  display: flex;
  justify-content: space-between;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  padding: var(--space-1) 0;
  border-bottom: 1px solid var(--color-divider);
}
.assumption-item span:last-child {
  font-family: var(--font-mono);
  color: var(--color-text);
  font-weight: 500;
}

/* ============================================================
   Tables
   ============================================================ */
.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums lining-nums;
}
.results-table th {
  text-align: left;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 2px solid var(--color-divider);
  background: var(--color-surface-offset);
  position: sticky;
  top: 0;
}
.results-table td {
  padding: var(--space-2) var(--space-4);
  border-bottom: 1px solid var(--color-divider);
}
.results-table tr:hover td {
  background: var(--color-primary-surface);
}
.results-table .text-right { text-align: right; }
.results-table .text-center { text-align: center; }
.results-table .highlight { font-weight: 600; color: var(--color-primary); }

/* Table scrollable wrapper */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
}

/* ============================================================
   Tabs
   ============================================================ */
.tabs {
  display: flex;
  gap: var(--space-1);
  border-bottom: 1px solid var(--color-divider);
  margin-bottom: var(--space-6);
  overflow-x: auto;
}
.tab-btn {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
  white-space: nowrap;
}
.tab-btn:hover { color: var(--color-text); }
.tab-btn.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ============================================================
   Tooltips & Info
   ============================================================ */
.info-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  border-radius: var(--radius-full);
  background: var(--color-surface-offset);
  color: var(--color-text-muted);
  font-size: 10px;
  font-weight: 700;
  cursor: help;
  margin-left: var(--space-1);
  vertical-align: middle;
}
.info-badge:hover {
  background: var(--color-primary-surface);
  color: var(--color-primary);
}

.tooltip {
  position: relative;
}
.tooltip::after {
  content: attr(data-tip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-text);
  color: var(--color-text-inverse);
  font-size: var(--text-xs);
  font-weight: 400;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  white-space: nowrap;
  max-width: 250px;
  white-space: normal;
  opacity: 0;
  pointer-events: none;
  transition: opacity 150ms;
  z-index: 10;
}
.tooltip:hover::after {
  opacity: 1;
}

/* ============================================================
   Score / Grade Badges
   ============================================================ */
.grade-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  height: 28px;
  padding: 0 var(--space-2);
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: var(--text-sm);
}
.grade-a { background: #e8f5e9; color: #2e7d32; }
.grade-b { background: #f1f8e9; color: #558b2f; }
.grade-c { background: #fff8e1; color: #f57f17; }
.grade-d { background: #fff3e0; color: #e65100; }
.grade-f { background: #fce4ec; color: #c62828; }

[data-theme="dark"] .grade-a { background: #1b3a1f; color: #6daa45; }
[data-theme="dark"] .grade-b { background: #2a3a1b; color: #8dba55; }
[data-theme="dark"] .grade-c { background: #3a331b; color: #e8af34; }
[data-theme="dark"] .grade-d { background: #3a2a1b; color: #bb653b; }
[data-theme="dark"] .grade-f { background: #3a1b22; color: #dd6974; }

/* ============================================================
   Print
   ============================================================ */
@media print {
  .header, [data-theme-toggle], .btn-run, .btn-ghost, .footer { display: none !important; }
  .panel { box-shadow: none; border: 1px solid #ccc; }
  body { background: white; color: black; }
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
  text-align: center;
  padding: var(--space-8) var(--space-6);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.footer a {
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer a:hover {
  color: var(--color-primary);
}

/* ============================================================
   Loading spinner
   ============================================================ */
@keyframes spin {
  to { transform: rotate(360deg); }
}
.spinner {
  width: 18px;
  height: 18px;
  border: 2px solid var(--color-text-inverse);
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  display: inline-block;
}

/* ============================================================
   Mobile
   ============================================================ */
@media (max-width: 640px) {
  .panel { padding: var(--space-5); }
  .main { padding: var(--space-4) var(--space-3); }
  .params-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }
  .kpi-row {
    grid-template-columns: 1fr 1fr;
  }
  .chart-grid {
    grid-template-columns: 1fr;
  }
  .results-header {
    flex-direction: column;
    align-items: flex-start;
  }
  .btn-run {
    max-width: 100%;
  }
}

@media (max-width: 380px) {
  .kpi-row {
    grid-template-columns: 1fr;
  }
}