@import "tailwindcss";

:root {
  --background: #ffffff;
  --foreground: #171717;
}

@theme inline {
  --color-background: var(--background);
  --color-foreground: var(--foreground);
  --font-sans: var(--font-geist-sans);
  --font-mono: var(--font-geist-mono);
}

body {
  background: var(--background);
  color: var(--foreground);
  font-family: Arial, Helvetica, sans-serif;
  margin: 0;
  padding: 0;
}

/* ========== APP LAYOUT ========== */

.app-container {
  min-height: 100vh;
}

/* ========== CONTROLS (screen only) ========== */

.controls {
  text-align: center;
  padding: 1.5rem 0.75rem 1.2rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.app-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 0 0 0.4rem;
}

.app-subtitle {
  font-size: 0.85rem;
  opacity: 0.9;
  margin: 0 0 1rem;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
  padding: 0 0.5rem;
}

.button-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: center;
  align-items: center;
  padding: 0 0.5rem;
}

.btn-difficulty {
  padding: 0.5rem 1rem;
  border: 2px solid rgba(255, 255, 255, 0.6);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.15);
  color: white;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  flex: 1 1 auto;
  min-width: 0;
}

.btn-difficulty:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.3);
  border-color: white;
}

.btn-difficulty.btn-active {
  background: white;
  color: #764ba2;
  border-color: white;
}

.btn-difficulty:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-print {
  padding: 0.5rem 1.2rem;
  border: none;
  border-radius: 8px;
  background: #fbbf24;
  color: #1a1a1a;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  width: 100%;
  margin-top: 0.3rem;
}

.btn-print:hover:not(:disabled) {
  background: #f59e0b;
  transform: scale(1.02);
}

.btn-print:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.generating-text {
  margin-top: 0.8rem;
  font-size: 0.9rem;
  animation: pulse 1.2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ========== RESPONSIVE: TABLET (>=600px) ========== */

@media screen and (min-width: 600px) {
  .controls {
    padding: 2rem 1.5rem 1.5rem;
  }

  .app-title {
    font-size: 1.8rem;
  }

  .app-subtitle {
    font-size: 1rem;
  }

  .btn-difficulty {
    padding: 0.6rem 1.4rem;
    font-size: 0.95rem;
    flex: 0 1 auto;
  }

  .btn-print {
    width: auto;
    padding: 0.6rem 1.6rem;
    font-size: 0.95rem;
    margin-top: 0;
    margin-left: 0.5rem;
  }
}

/* ========== RESPONSIVE: DESKTOP (>=900px) ========== */

@media screen and (min-width: 900px) {
  .controls {
    padding: 2.5rem 2rem 1.5rem;
  }

  .app-title {
    font-size: 2rem;
  }
}

/* ========== SEO CONTENT (hidden visually, accessible to crawlers) ========== */

.seo-content {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.seo-content h2 {
  font-size: 1rem;
  font-weight: 700;
  color: #374151;
  margin: 0 0 0.5rem;
}

.seo-content p {
  margin: 0;
}

/* ========== PRINT AREA (visible on screen + print) ========== */

.print-area {
  padding: 0.5rem;
}

.print-page {
  max-width: 210mm;
  margin: 0 auto 1.5rem;
  padding: 0.75rem;
  background: white;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  overflow-x: auto;
}

.page-title {
  text-align: center;
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0.2rem 0 0.6rem;
  color: #1a1a1a;
}

.sudoku-grid-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.8rem;
  justify-items: center;
}

@media screen and (min-width: 480px) {
  .sudoku-grid-container {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.6rem 0.8rem;
  }
}

@media screen and (min-width: 600px) {
  .print-area {
    padding: 1rem;
  }

  .print-page {
    padding: 1rem;
  }

  .page-title {
    font-size: 1.3rem;
    margin: 0.3rem 0 0.8rem;
  }

  .sudoku-grid-container {
    gap: 0.8rem 1.2rem;
  }
}

@media screen and (min-width: 900px) {
  .print-page {
    margin: 0 auto 2rem;
  }
}

/* ========== SUDOKU GRID ========== */

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

.sudoku-number {
  font-size: 0.75rem;
  font-weight: 600;
  color: #6b7280;
  margin: 0 0 0.15rem;
}

.sudoku-table {
  border-collapse: collapse;
  width: 100%;
  max-width: 270px;
}

.sudoku-cell {
  width: clamp(22px, 4.5vw, 32px);
  height: clamp(22px, 4.5vw, 32px);
  text-align: center;
  vertical-align: middle;
  font-size: clamp(0.65rem, 1.8vw, 0.95rem);
  font-weight: 500;
  border: 1px solid #bbb;
  padding: 0;
}

@media screen and (min-width: 480px) {
  .sudoku-cell {
    width: clamp(24px, 3.2vw, 30px);
    height: clamp(24px, 3.2vw, 30px);
    font-size: clamp(0.7rem, 1.5vw, 0.9rem);
  }

  .sudoku-table {
    max-width: 280px;
  }
}

@media screen and (min-width: 900px) {
  .sudoku-cell {
    width: 30px;
    height: 30px;
    font-size: 0.9rem;
  }

  .sudoku-table {
    max-width: 300px;
  }
}

.border-l-thick { border-left: 2.5px solid #222 !important; }
.border-r-thick { border-right: 2.5px solid #222 !important; }
.border-t-thick { border-top: 2.5px solid #222 !important; }
.border-b-thick { border-bottom: 2.5px solid #222 !important; }

.given-digit {
  color: #1a1a1a;
  font-weight: 700;
}

.solution-digit {
  color: #1a1a1a;
  font-weight: 500;
}

/* ========== PRINT STYLES ========== */

.no-print {
  display: block;
}

@media print {
  @page {
    size: A4 portrait;
    margin: 8mm 10mm 8mm 10mm;
  }

  body {
    background: white !important;
    color: black !important;
    margin: 0;
    padding: 0;
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
  }

  .no-print {
    display: none !important;
  }

  .print-area {
    padding: 0;
  }

  .print-page {
    border: none !important;
    border-radius: 0 !important;
    margin: 0;
    padding: 0;
    max-width: none;
    page-break-after: always;
    break-after: page;
    height: 100%;
    display: flex;
    flex-direction: column;
  }

  .print-page:last-child {
    page-break-after: avoid;
  }

  .page-title {
    font-size: 12pt;
    margin: 0 0 2mm;
    color: black;
  }

  .sudoku-grid-container {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2mm 6mm;
    justify-items: center;
    align-content: start;
  }

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

  .sudoku-number {
    font-size: 7pt;
    color: #333;
    margin: 0 0 0.5mm;
  }

  .sudoku-cell {
    width: 8mm;
    height: 8mm;
    font-size: 10pt;
    border: 1pt solid #666;
  }

  .border-l-thick { border-left: 2.5pt solid #000 !important; }
  .border-r-thick { border-right: 2.5pt solid #000 !important; }
  .border-t-thick { border-top: 2.5pt solid #000 !important; }
  .border-b-thick { border-bottom: 2.5pt solid #000 !important; }

  .given-digit {
    color: black;
    font-weight: 700;
  }

  .solution-digit {
    color: black;
    font-weight: 500;
  }
}