/* --- LEARN VIEW --- */
.learn-view {
  display: flex;
  flex-direction: column;
  height: 100%;
  width: 100%;
  padding: 16px;
  padding-top: calc(env(safe-area-inset-top, 20px) + 24px);
  box-sizing: border-box;
  overflow-y: auto;
}

/* Decks Overview */
.decks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.deck-card {
  background: var(--surface-2);
  border-radius: 20px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  cursor: pointer;
  transition: transform 0.2s, background 0.2s;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.deck-card:hover {
  transform: translateY(-4px);
  background: var(--surface-3);
}

.deck-icon-wrapper {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.deck-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.deck-stats {
  font-size: 13px;
  color: var(--text-secondary);
  display: flex;
  justify-content: space-between;
}

.due-badge {
  background: rgba(193, 131, 240, 0.2);
  color: #c183f0;
  padding: 2px 8px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 12px;
}

/* Study Mode - Progressive Blur Card */
.study-container {
  display: flex;
  flex-direction: column;
  height: 100%;
  align-items: center;
  justify-content: center;
  padding: 20px 0;
  box-sizing: border-box;
  overflow: hidden;
}

.flashcard-stack {
  position: relative;
  width: 100%;
  max-width: 380px;
  aspect-ratio: 3/4;
  margin-bottom: 30px;
  min-height: 0; /* Allow shrinking on small screens */
  flex-shrink: 1;
}

.flashcard-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  perspective: 1000px;
}

.flashcard-wrapper.stacked-1 {
  z-index: 2;
  transform-origin: top center;
  transform: translateY(-16px) scale(0.92);
  opacity: 0.8;
  filter: brightness(0.8);
  pointer-events: none;
}

.flashcard-wrapper.stacked-2 {
  z-index: 1;
  transform-origin: top center;
  transform: translateY(-32px) scale(0.84);
  opacity: 0.5;
  filter: brightness(0.6);
  pointer-events: none;
}

.flashcard-wrapper.current {
  z-index: 3;
  position: relative;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s cubic-bezier(0.4, 0.0, 0.2, 1);
  transform-style: preserve-3d;
  cursor: pointer;
}

.flashcard-inner.flipped {
  transform: rotateY(180deg);
}

.flashcard-face {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  border-radius: 24px;
  overflow: hidden;
  background: #1a1a20;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
  transform: translateZ(0);
  box-sizing: border-box;
  border: 1px solid rgba(255, 255, 255, 0.08);
  /* Ultimate WebKit/Android WebView clipping fix */
  -webkit-clip-path: inset(0 round 24px);
  clip-path: inset(0 round 24px);
}

.flashcard-face::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  border-radius: 24px;
  /* More intense inner mask to hide ANY remaining subpixel bleeding */
  box-shadow: inset 0 0 0 4px #000;
  pointer-events: none;
  z-index: 10;
}

.flashcard-back {
  transform: rotateY(180deg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: 40px 24px 30px 24px;
  background: #121216;
  /* Use inset shadow instead of border to prevent 3D sub-pixel bleeding on Chromium/Android */
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
  overflow-y: auto;
  overflow-x: hidden;
}

/* The Progressive Blur Magic */
.flashcard-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
  border-radius: 24px;
}

.flashcard-blur-overlay {
  position: absolute;
  bottom: -2px; /* Pull down slightly to cover any sub-pixel gap */
  left: -2px;
  right: -2px;
  height: 65%; /* Make slightly larger to ensure full coverage */
  z-index: 2;
  border-bottom-left-radius: 24px;
  border-bottom-right-radius: 24px;
  /* Progressive Blur trick */
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  mask-image: linear-gradient(to bottom, transparent 0%, black 60%);
  -webkit-mask-image: linear-gradient(to bottom, transparent 0%, black 60%);
  /* Dark fade */
  background: linear-gradient(to bottom, transparent 0%, rgba(0, 0, 0, 0.9) 80%, #000000 100%);
}

.flashcard-content {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 3;
  padding: 30px 20px;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.flashcard-title {
  font-size: 24px;
  font-weight: 700;
  color: #ffffff;
  margin: 0;
  text-shadow: 0 2px 8px rgba(0,0,0,0.5);
}

.flashcard-subtitle {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.8);
  line-height: 1.4;
}

/* Feedback Buttons */
.feedback-controls {
  display: flex;
  gap: 12px;
  width: 100%;
  max-width: 380px;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.3s, transform 0.3s;
  pointer-events: none;
}

.feedback-controls.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.btn-feedback {
  flex: 1;
  padding: 12px 0;
  border-radius: 14px;
  border: none;
  font-weight: 600;
  font-size: 13px;
  color: white;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.btn-again { background: #ff453a; }
.btn-hard { background: #ff9f0a; }
.btn-good { background: #32d74b; }
.btn-easy { background: #0a84ff; }

.feedback-time {
  font-size: 10px;
  opacity: 0.8;
  font-weight: 500;
}