/* ==========================================================================
   Alphabet Shift Spectrum - Base Styles
   ========================================================================== */

/* CSS Custom Properties */
:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #3b82f6;
  --color-success: #16a34a;
  --color-danger: #dc2626;
  --color-warning: #ca8a04;

  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-border: #e2e8f0;
  --color-border-dark: #cbd5e1;

  /* Heatmap colors */
  --heatmap-zero: #f1f5f9;
  --heatmap-low: #bbf7d0;
  --heatmap-mid: #fef08a;
  --heatmap-high: #fed7aa;
  --heatmap-max: #fca5a5;

  /* Low frequency letter highlight */
  --low-freq-bg: #fef3c7;
  --low-freq-border: #f59e0b;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;

  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
}

/* Reset */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
  line-height: 1.6;
  background-color: var(--color-bg);
  color: var(--color-text);
}

/* Typography */
h1, h2, h3 {
  margin: 0 0 var(--spacing-md);
  line-height: 1.3;
}

h1 {
  font-size: 1.5rem;
}

h2 {
  font-size: 1.125rem;
  color: var(--color-text);
  border-bottom: 2px solid var(--color-primary);
  padding-bottom: var(--spacing-sm);
}

p {
  margin: 0 0 var(--spacing-md);
}

/* Base element styles */
button {
  font-family: inherit;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  transition: background-color 0.2s, transform 0.1s;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

button:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

textarea {
  font-family: inherit;
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  resize: vertical;
  transition: border-color 0.2s;
}

textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

label {
  display: block;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

/* Button variants */
.btn-primary {
  background-color: var(--color-primary);
  color: white;
  font-weight: 600;
  min-height: 44px;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-dark);
}

.btn-primary:active:not(:disabled) {
  transform: scale(0.98);
}

/* Table styles */
table {
  border-collapse: collapse;
  width: 100%;
}

th, td {
  border: 1px solid var(--color-border);
  padding: var(--spacing-xs) var(--spacing-sm);
  text-align: center;
}

th {
  background-color: var(--color-bg);
  font-weight: 600;
  font-size: 0.75rem;
}

td {
  font-size: 0.875rem;
}

/* Low frequency letter columns */
th.low-freq-letter,
td.low-freq-letter {
  background-color: var(--low-freq-bg);
}

/* Utility classes */
.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.placeholder-message {
  color: var(--color-text-secondary);
  text-align: center;
  padding: var(--spacing-xl);
  font-style: italic;
}

/* Legend */
.legend-item {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  margin-right: var(--spacing-md);
  font-size: 0.875rem;
}

.legend-color {
  display: inline-block;
  width: 1rem;
  height: 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

.legend-color.low {
  background-color: var(--heatmap-low);
}

.legend-color.mid {
  background-color: var(--heatmap-mid);
}

.legend-color.high {
  background-color: var(--heatmap-max);
}

/* Heatmap hover highlighting */
.heatmap-highlight-row {
  outline: 2px solid var(--color-primary);
  outline-offset: -1px;
  z-index: 1;
  position: relative;
}

.heatmap-highlight-col {
  outline: 2px solid var(--color-primary);
  outline-offset: -1px;
  z-index: 1;
  position: relative;
}

.heatmap-highlight-cell {
  outline: 3px solid var(--color-primary-dark) !important;
  outline-offset: -1px;
  z-index: 2;
  position: relative;
  font-weight: 700;
}

/* Formula Display */
.threshold-formula-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  margin-top: var(--spacing-md);
}

.threshold-formula {
  display: inline-flex;
  align-items: center;
  gap: 0.25em;
  background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 100%);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-primary-light);
  font-family: "Cambria Math", "Times New Roman", serif;
  font-size: 1.125rem;
}

.formula-label {
  font-weight: 600;
  color: var(--color-text);
}

.formula-equals {
  color: var(--color-text-secondary);
  margin: 0 0.25em;
}

.formula-ceil {
  font-size: 1.5em;
  color: var(--color-primary);
  font-weight: 300;
}

.formula-content {
  color: var(--color-text);
}

.formula-var {
  font-style: italic;
  color: var(--color-primary-dark);
  font-weight: 600;
}

.formula-const {
  font-style: italic;
  color: #059669;
  font-weight: 600;
}

.formula-note {
  text-align: center;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-top: var(--spacing-sm);
  margin-bottom: 0;
}

/* Help Button (square - opens modal) */
.help-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: white;
  font-weight: 700;
  font-size: 0.875rem;
  padding: 0;
  flex-shrink: 0;
}

.help-btn:hover {
  background-color: var(--color-primary-dark);
  transform: scale(1.05);
}

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md);
}

.modal[hidden] {
  display: none;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
  position: relative;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  max-width: 600px;
  max-height: 90vh;
  overflow-y: auto;
  width: 100%;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  background-color: var(--color-surface);
}

.modal-header h3 {
  margin: 0;
  font-size: 1.125rem;
}

.modal-close {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background-color: var(--color-bg);
  color: var(--color-text-secondary);
  font-size: 1.25rem;
  padding: 0;
  line-height: 1;
}

.modal-close:hover {
  background-color: var(--color-border);
  color: var(--color-text);
}

.modal-body {
  padding: var(--spacing-lg);
}

.modal-body h4 {
  font-size: 1rem;
  color: var(--color-primary-dark);
  margin: var(--spacing-md) 0 var(--spacing-sm);
}

.modal-body h4:first-child {
  margin-top: 0;
}

.modal-body p {
  margin: 0 0 var(--spacing-md);
  line-height: 1.7;
}

.modal-body ul {
  margin: 0 0 var(--spacing-md);
  padding-left: var(--spacing-lg);
}

.modal-body li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.6;
}

/* Filter Results Header */
.filter-results-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
}

.filter-results-header h3 {
  font-size: 0.9375rem;
  margin: 0;
  color: var(--color-text);
}

/* Tooltip */
.tooltip-container {
  position: relative;
  display: inline-flex;
}

/* Help Icon (circle - shows tooltip on hover) */
.help-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.25rem;
  height: 1.25rem;
  border-radius: 50%;
  background-color: var(--color-text-secondary);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  cursor: help;
}

.tooltip-text {
  visibility: hidden;
  opacity: 0;
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--color-text);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  font-size: 0.8125rem;
  line-height: 1.5;
  white-space: nowrap;
  z-index: 100;
  margin-bottom: var(--spacing-xs);
  transition: opacity 0.2s, visibility 0.2s;
}

.tooltip-text::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--color-text);
}

.tooltip-container:hover .tooltip-text {
  visibility: visible;
  opacity: 1;
}