:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --success: #16a34a;
  --success-bg: #dcfce7;
  --warning: #d97706;
  --warning-bg: #fef3c7;
  --danger: #dc2626;
  --danger-bg: #fee2e2;
  --neutral: #64748b;
  --neutral-bg: #f1f5f9;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius: 12px;
  --radius-sm: 6px;
  --font: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.logo-icon {
  width: 28px;
  height: 28px;
  color: var(--primary);
}

.logo-text strong {
  color: var(--primary);
}

.header-nav {
  display: flex;
  gap: 20px;
}

.header-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
}

.header-nav a:hover {
  color: var(--primary);
}

/* Hero Section */
.hero-section {
  text-align: center;
  padding: 40px 0 24px;
}

.hero-section h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.025em;
  margin-bottom: 12px;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0 auto;
}

/* Ad Placement Containers */
.ad-container {
  margin: 24px 0;
  display: flex;
  justify-content: center;
}

.ad-slot {
  width: 100%;
  max-width: 728px;
  min-height: 90px;
  background: #f1f5f9;
  border: 1px dashed #cbd5e1;
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 8px;
  position: relative;
}

.ad-label {
  position: absolute;
  top: 4px;
  right: 8px;
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #94a3b8;
}

.ad-placeholder-content {
  font-size: 0.85rem;
  color: #64748b;
  font-weight: 500;
}

/* Calculator Grid */
.calculator-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  margin-bottom: 40px;
}

@media (max-width: 860px) {
  .calculator-grid {
    grid-template-columns: 1fr;
  }
}

/* Card */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
  padding: 24px;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
}

.card-header h2 {
  font-size: 1.3rem;
  font-weight: 700;
}

/* Preset Buttons */
.preset-buttons {
  display: flex;
  align-items: center;
  gap: 6px;
}

.preset-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
}

.btn-preset {
  background: var(--neutral-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 8px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-preset:hover {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
}

/* Form Styles */
.form-section-title {
  font-size: 0.85rem;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--primary);
  margin: 16px 0 12px;
}

.form-section-title:first-child {
  margin-top: 0;
}

.form-group {
  margin-bottom: 16px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: #334155;
}

.tooltip {
  color: var(--neutral);
  cursor: help;
  font-size: 0.85rem;
}

.input-prefix-wrapper,
.input-suffix-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
}

.input-prefix {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
  user-select: none;
  line-height: 1;
  z-index: 2;
}

.input-suffix {
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
  user-select: none;
  line-height: 1;
  z-index: 2;
}

input[type="number"],
select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-family: inherit;
  background-color: #ffffff;
  color: var(--text);
  transition: border-color 0.15s, box-shadow 0.15s;
}

/* Explicit offset padding for prefix and suffix inputs */
.input-prefix-wrapper input[type="number"],
.input-prefix-wrapper input {
  padding-left: 32px;
}

.input-suffix-wrapper input[type="number"],
.input-suffix-wrapper input {
  padding-right: 32px;
}

input[type="number"]:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.field-hint {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.form-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
}

.btn {
  padding: 12px 20px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all 0.15s;
}

.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
  flex: 2;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
}

.btn-secondary {
  background-color: var(--neutral-bg);
  color: var(--text);
  border: 1px solid var(--border);
  flex: 1;
}

.btn-secondary:hover {
  background-color: #e2e8f0;
}

/* Results Panel */
.results-card {
  display: flex;
  flex-direction: column;
}

.badge {
  display: inline-block;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge-neutral {
  background-color: var(--neutral-bg);
  color: var(--neutral);
}

.badge-success {
  background-color: var(--success-bg);
  color: var(--success);
}

.badge-warning {
  background-color: var(--warning-bg);
  color: var(--warning);
}

.badge-danger {
  background-color: var(--danger-bg);
  color: var(--danger);
}

.badge-primary {
  background-color: var(--primary-light);
  color: var(--primary);
}

.dscr-hero-box {
  background: var(--neutral-bg);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  margin-bottom: 24px;
  transition: all 0.3s ease;
}

.dscr-hero-box.status-success {
  background: var(--success-bg);
  border: 1px solid rgba(22, 163, 74, 0.3);
}

.dscr-hero-box.status-warning {
  background: var(--warning-bg);
  border: 1px solid rgba(217, 119, 6, 0.3);
}

.dscr-hero-box.status-danger {
  background: var(--danger-bg);
  border: 1px solid rgba(220, 38, 38, 0.3);
}

.dscr-label {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 700;
  color: var(--text-muted);
}

.dscr-value {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.1;
  margin: 6px 0;
  color: var(--text);
}

.dscr-status {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
}

/* Breakdown Grid */
.breakdown-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 24px;
}

@media (max-width: 480px) {
  .breakdown-grid {
    grid-template-columns: 1fr;
  }
}

.breakdown-item {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px;
  display: flex;
  flex-direction: column;
}

.breakdown-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
}

.breakdown-value {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
  margin: 4px 0 2px;
}

.breakdown-subtext {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* Benchmark Meter */
.benchmark-meter {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
}

.meter-label-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.meter-bar-track {
  position: relative;
  height: 12px;
  border-radius: 6px;
  display: flex;
  overflow: visible;
  margin-bottom: 8px;
}

.meter-segment {
  height: 100%;
}

.seg-danger {
  width: 35%;
  background-color: #ef4444;
  border-top-left-radius: 6px;
  border-bottom-left-radius: 6px;
}

.seg-warning {
  width: 20%;
  background-color: #f59e0b;
}

.seg-good {
  width: 25%;
  background-color: #10b981;
}

.seg-excellent {
  width: 20%;
  background-color: #3b82f6;
  border-top-right-radius: 6px;
  border-bottom-right-radius: 6px;
}

.meter-pointer {
  position: absolute;
  top: -4px;
  width: 6px;
  height: 20px;
  background: #0f172a;
  border: 2px solid #ffffff;
  border-radius: 3px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.4);
  transform: translateX(-50%);
  transition: left 0.4s ease;
}

.meter-scale-markers {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* Educational Info Section */
.info-section {
  margin-top: 40px;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.info-article {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-sm);
}

.info-article h2 {
  font-size: 1.4rem;
  font-weight: 800;
  margin-bottom: 16px;
  color: var(--text);
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 8px;
}

.info-article p {
  margin-bottom: 14px;
  color: #334155;
}

.formula-box {
  background: var(--neutral-bg);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-sm);
  padding: 20px;
  margin: 16px 0;
}

.formula-line {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
}

.formula-sub ul {
  padding-left: 20px;
  margin-top: 8px;
}

.formula-sub li {
  margin-bottom: 6px;
  color: #475569;
}

/* Table */
.table-responsive {
  overflow-x: auto;
  margin-top: 16px;
}

.benchmark-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.benchmark-table th,
.benchmark-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.benchmark-table th {
  background-color: var(--neutral-bg);
  font-weight: 700;
  color: #334155;
}

.text-danger { color: var(--danger); }
.text-warning { color: var(--warning); }
.text-success { color: var(--success); }
.text-primary { color: var(--primary); }

/* Footer */
.site-footer {
  margin-top: 60px;
  border-top: 1px solid var(--border);
  background: #ffffff;
  padding: 24px 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}