/* Paper Puzzle — Common Styles */

:root {
  --bg-start:   #1a1a2e;
  --bg-end:     #16213e;
  --gold-start: #FFD700;
  --gold-end:   #FFA500;
  --purple-start: #667eea;
  --purple-end:   #764ba2;
  --text:       #ffffff;
  --text-muted: #aaaaaa;
  --panel-bg:   rgba(255,255,255,0.06);
  --panel-border: rgba(255,255,255,0.12);
  --btn-radius: 8px;
}

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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, var(--bg-start) 0%, var(--bg-end) 100%);
  color: var(--text);
  min-height: 100vh;
}

/* ── Buttons ─────────────────────────────────────────────────────── */

.btn {
  display: inline-block;
  background: linear-gradient(135deg, var(--purple-start) 0%, var(--purple-end) 100%);
  color: var(--text);
  border: none;
  padding: 13px 26px;
  font-size: 1em;
  border-radius: var(--btn-radius);
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s;
  font-family: inherit;
  font-weight: 600;
  box-shadow: 0 4px 14px rgba(0,0,0,0.35);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.45);
}

.btn:active {
  transform: translateY(0);
}

.btn-gold {
  background: linear-gradient(135deg, var(--gold-start) 0%, var(--gold-end) 100%);
  color: #222;
}

.btn-sm {
  padding: 8px 18px;
  font-size: 0.9em;
}

.btn-ghost {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
}

/* ── Nav bar ─────────────────────────────────────────────────────── */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  padding: 0 20px;
  gap: 14px;
  z-index: 100;
  border-bottom: 1px solid var(--panel-border);
}

.nav-title {
  font-size: 1.25em;
  font-weight: 700;
  background: linear-gradient(45deg, var(--gold-start), var(--gold-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  flex: 1;
  text-align: center;
}

/* ── Index page ──────────────────────────────────────────────────── */

.page-center {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px;
}

.hero {
  text-align: center;
  margin-bottom: 48px;
}

.hero h1 {
  font-size: 3em;
  margin-bottom: 12px;
  background: linear-gradient(45deg, var(--gold-start), var(--gold-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.15em;
  color: var(--text-muted);
  max-width: 520px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  max-width: 700px;
  width: 100%;
  margin-bottom: 36px;
}

.feature-card {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  padding: 22px 18px;
  text-align: center;
}

.feature-icon {
  font-size: 2.4em;
  margin-bottom: 10px;
}

.feature-card h3 {
  font-size: 1em;
  margin-bottom: 6px;
  color: var(--text);
}

.feature-card p {
  font-size: 0.85em;
  color: var(--text-muted);
  line-height: 1.4;
}

.cta-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}

/* ── Game page ───────────────────────────────────────────────────── */

.game-layout {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

.game-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.level-select {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  color: var(--text);
  padding: 7px 12px;
  border-radius: var(--btn-radius);
  font-size: 0.92em;
  font-family: inherit;
  cursor: pointer;
}

.level-select:focus {
  outline: none;
  border-color: var(--purple-start);
}

.canvas-area {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 12px;
  overflow: hidden;
}

#gameCanvas {
  display: block;
  border-radius: 10px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.55);
  cursor: grab;
  max-width: 100%;
  max-height: 100%;
}

#gameCanvas:active {
  cursor: grabbing;
}

/* ── Win overlay ─────────────────────────────────────────────────── */

.win-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  animation: fadeIn 0.4s ease;
}

.win-overlay.hidden {
  display: none;
}

.win-card {
  background: linear-gradient(135deg, #1e1e3e 0%, #2a1a5e 100%);
  border: 2px solid var(--gold-start);
  border-radius: 18px;
  padding: 44px 52px;
  text-align: center;
  box-shadow: 0 20px 60px rgba(0,0,0,0.7);
  animation: popIn 0.35s cubic-bezier(0.34,1.56,0.64,1);
}

.win-card h2 {
  font-size: 2.4em;
  margin-bottom: 8px;
  background: linear-gradient(45deg, var(--gold-start), var(--gold-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.win-card p {
  color: var(--text-muted);
  margin-bottom: 28px;
  font-size: 1.05em;
}

.win-btns {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes popIn {
  from { transform: scale(0.7); opacity: 0; }
  to   { transform: scale(1);   opacity: 1; }
}

/* ── Responsive ──────────────────────────────────────────────────── */

@media (max-width: 600px) {
  .hero h1 { font-size: 2em; }
  .nav-title { font-size: 1em; }
  .win-card { padding: 28px 24px; }
  .win-card h2 { font-size: 1.8em; }
}