/* =========================================================
   BÀI 12 - PHẦN MỀM THIẾT KẾ ĐỒ HOẠ
   TỐI ƯU ANIMATION 60FPS
   ========================================================= */

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

:root {
  --bg-1: #e0f2fe;
  --bg-2: #ede9fe;
  --bg-3: #fce7f3;
  --blue: #3b82f6;
  --purple: #8b5cf6;
  --emerald: #10b981;
  --amber: #f59e0b;
  --rose: #f43f5e;
  --cyan: #06b6d4;
  --text: #1e293b;
  --text-muted: #475569;
  --card-bg: rgba(255, 255, 255, 0.72);
  --card-border: rgba(148, 163, 184, 0.3);
}

html, body {
  height: 100%;
  font-family: 'Be Vietnam Pro', sans-serif;
  background: linear-gradient(135deg, var(--bg-1) 0%, var(--bg-2) 50%, var(--bg-3) 100%);
  color: var(--text);
  overflow: hidden;
}

/* ===== BACKGROUND ===== */
.bg-layer {
  position: fixed;
  inset: 0;
  z-index: -10;
  overflow: hidden;
  pointer-events: none;
  transform: translateZ(0);
}

.bg-gradient {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #e0f2fe 0%, #ede9fe 50%, #fce7f3 100%);
}

.bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(59, 130, 246, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(59, 130, 246, 0.08) 1px, transparent 1px);
  background-size: 60px 60px;
}

.bg-grid::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, transparent 0%, rgba(224, 242, 254, 0.5) 100%);
  pointer-events: none;
}

.bg-blob {
  position: absolute;
  border-radius: 50%;
  opacity: 0.5;
  transform: translateZ(0);
  will-change: transform;
  backface-visibility: hidden;
  animation: floatBlob 18s ease-in-out infinite;
  background: radial-gradient(circle, currentColor 0%, transparent 70%);
}

.blob-1 { width: 600px; height: 600px; color: #93c5fd; top: -200px; left: -180px; }
.blob-2 { width: 700px; height: 700px; color: #c4b5fd; bottom: -260px; right: -220px; animation-delay: 6s; }
.blob-3 { width: 500px; height: 500px; color: #fbcfe8; top: 38%; left: 42%; animation-delay: 10s; }

@keyframes floatBlob {
  0%, 100% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(40px, -40px, 0) scale(1.12); }
}

/* ===== SHAPES ===== */
.shape {
  position: absolute;
  opacity: 0.35;
  transform: translateZ(0);
  backface-visibility: hidden;
}

.s1, .s6, .s11, .s15, .s19 {
  will-change: transform;
  animation: floatShape 12s ease-in-out infinite;
}

.s3, .s8, .s12, .s17 { animation-delay: 3s; }

@keyframes floatShape {
  0%, 100% { transform: translate3d(0, 0, 0) rotate(0deg); }
  50% { transform: translate3d(0, -25px, 0) rotate(15deg); }
}

.shape-circle { border-radius: 50%; border: 2px solid #3b82f6; }
.shape-square { border: 2px solid #8b5cf6; border-radius: 6px; }
.shape-triangle { width: 0; height: 0; border-left: 22px solid transparent; border-right: 22px solid transparent; border-bottom: 38px solid #10b981; background: transparent; }
.shape-ring { border-radius: 50%; border: 4px solid #f59e0b; }
.shape-plus { font-size: 3rem; font-weight: 900; color: #3b82f6; line-height: 1; font-family: 'Fira Code', monospace; }
.shape-diamond { width: 40px; height: 40px; border: 2px solid #f43f5e; border-radius: 6px; }
.shape-pentagon { width: 44px; height: 44px; background: #06b6d4; clip-path: polygon(50% 0%, 100% 38%, 82% 100%, 18% 100%, 0% 38%); }
.shape-hexagon { width: 44px; height: 44px; background: #8b5cf6; clip-path: polygon(25% 0%, 75% 0%, 100% 50%, 75% 100%, 25% 100%, 0% 50%); }
.shape-heart { font-size: 2rem; color: #ec4899; }
.shape-cross { font-size: 2.5rem; color: #10b981; }

.s1 { width: 70px; height: 70px; top: 12%; left: 8%; }
.s2 { width: 50px; height: 50px; top: 20%; right: 12%; }
.s3 { top: 65%; left: 6%; }
.s4 { width: 80px; height: 80px; bottom: 15%; right: 8%; }
.s5 { top: 45%; right: 20%; }
.s6 { bottom: 30%; left: 20%; border-color: #ec4899; }
.s7 { width: 60px; height: 60px; top: 8%; left: 45%; border-color: #06b6d4; }
.s8 { width: 55px; height: 55px; bottom: 12%; left: 35%; }
.s9 { width: 45px; height: 45px; top: 35%; left: 30%; border-color: #10b981; }
.s10 { top: 75%; right: 30%; color: #8b5cf6; }
.s11 { top: 25%; left: 22%; }
.s12 { bottom: 22%; right: 25%; }
.s13 { top: 15%; right: 35%; }
.s14 { bottom: 40%; left: 10%; }
.s15 { width: 35px; height: 35px; top: 55%; right: 6%; border-color: #f43f5e; }
.s16 { width: 40px; height: 40px; top: 80%; left: 48%; border-color: #f59e0b; }
.s17 { width: 55px; height: 55px; top: 5%; right: 8%; border-color: #8b5cf6; }
.s18 { bottom: 5%; left: 15%; }
.s19 { top: 60%; right: 42%; border-color: #06b6d4; }
.s20 { top: 5%; left: 25%; color: #f43f5e; }

/* ===== PROGRESS & COUNTER ===== */
.progress-container {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 5px;
  background: rgba(148, 163, 184, 0.2);
  z-index: 100;
}

.progress-bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6);
  transition: width 0.35s cubic-bezier(0.22, 0.61, 0.36, 1);
  border-radius: 0 5px 5px 0;
}

.slide-counter {
  position: fixed;
  top: 20px; right: 30px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid rgba(148, 163, 184, 0.3);
  padding: 8px 16px;
  border-radius: 30px;
  font-family: 'Fira Code', monospace;
  font-weight: 600;
  font-size: 0.9rem;
  backdrop-filter: blur(10px);
  z-index: 100;
  color: #1e293b;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}

.slide-counter span { color: #3b82f6; }

/* ===== DECK & SLIDE ===== */
.deck {
  position: relative;
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: translateZ(0);
}

.slide {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 50px 40px;
  opacity: 0;
  visibility: hidden;
  overflow-y: auto;
  transform: translateZ(0);
  backface-visibility: hidden;
  will-change: opacity, transform;
}

.slide.active {
  opacity: 1;
  visibility: visible;
  animation-duration: 0.5s;
  animation-fill-mode: both;
  animation-timing-function: cubic-bezier(0.22, 0.61, 0.36, 1);
}

.slide.active.anim-fade { animation-name: slideFade; }
.slide.active.anim-slide-left { animation-name: slideLeft; }
.slide.active.anim-slide-right { animation-name: slideRight; }
.slide.active.anim-slide-up { animation-name: slideUp; }
.slide.active.anim-zoom-in { animation-name: zoomIn; }
.slide.active.anim-rotate-in { animation-name: rotateIn; }
.slide.active.anim-flip-x { animation-name: flipX; }

@keyframes slideFade { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideLeft {
  from { opacity: 0; transform: translate3d(60px, 0, 0); }
  to { opacity: 1; transform: translate3d(0, 0, 0); }
}
@keyframes slideRight {
  from { opacity: 0; transform: translate3d(-60px, 0, 0); }
  to { opacity: 1; transform: translate3d(0, 0, 0); }
}
@keyframes slideUp {
  from { opacity: 0; transform: translate3d(0, 50px, 0); }
  to { opacity: 1; transform: translate3d(0, 0, 0); }
}
@keyframes zoomIn {
  from { opacity: 0; transform: scale3d(0.88, 0.88, 1); }
  to { opacity: 1; transform: scale3d(1, 1, 1); }
}
@keyframes rotateIn {
  from { opacity: 0; transform: rotate(-4deg) scale3d(0.94, 0.94, 1); }
  to { opacity: 1; transform: rotate(0deg) scale3d(1, 1, 1); }
}
@keyframes flipX {
  from { opacity: 0; transform: perspective(1200px) rotateY(50deg); }
  to { opacity: 1; transform: perspective(1200px) rotateY(0deg); }
}

/* ===== ITEM ANIMATIONS ===== */
.slide-content {
  width: 100%;
  max-width: 1150px;
}

.anim-item {
  opacity: 0;
  transform: translate3d(0, 20px, 0);
  backface-visibility: hidden;
  will-change: opacity, transform;
  transition:
    opacity 0.5s cubic-bezier(0.22, 0.61, 0.36, 1),
    transform 0.5s cubic-bezier(0.22, 0.61, 0.36, 1);
}

.slide.active .anim-item {
  opacity: 1;
  transform: translate3d(0, 0, 0);
}

.slide.active .anim-item:nth-child(1) { transition-delay: 0.10s; }
.slide.active .anim-item:nth-child(2) { transition-delay: 0.18s; }
.slide.active .anim-item:nth-child(3) { transition-delay: 0.26s; }
.slide.active .anim-item:nth-child(4) { transition-delay: 0.34s; }
.slide.active .anim-item:nth-child(5) { transition-delay: 0.42s; }
.slide.active .anim-item:nth-child(6) { transition-delay: 0.50s; }
.slide.active .anim-item:nth-child(7) { transition-delay: 0.58s; }
.slide.active .anim-item:nth-child(8) { transition-delay: 0.66s; }

.slide.active .delay-1 { transition-delay: 0.20s !important; }
.slide.active .delay-2 { transition-delay: 0.30s !important; }
.slide.active .delay-3 { transition-delay: 0.40s !important; }
.slide.active .delay-4 { transition-delay: 0.50s !important; }
.slide.active .delay-5 { transition-delay: 0.60s !important; }
.slide.active .delay-6 { transition-delay: 0.70s !important; }
.slide.active .delay-7 { transition-delay: 0.80s !important; }

/* ===== SLIDE HEADER ===== */
.slide-header {
  margin-bottom: 22px;
  text-align: center;
}

.step-badge {
  display: inline-block;
  background: linear-gradient(90deg, var(--blue), var(--purple));
  color: white;
  padding: 6px 18px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 10px;
  animation: pulseBadge 2.5s ease-in-out infinite;
}

@keyframes pulseBadge {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.04); }
}

.slide-header h2 {
  font-size: clamp(1.4rem, 2.6vw, 2rem);
  font-weight: 800;
}

.gradient-text {
  background: linear-gradient(90deg, #60a5fa, #a78bfa, #34d399, #60a5fa);
  background-size: 300% 100%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: gradientMove 4s ease infinite;
}

@keyframes gradientMove {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* ===== CARD BASE ===== */
.task-card, .quiz-card, .concept-card, .compare-card, .mini-card,
.step-card, .tf-item, .summary-card, .zone-card, .step-card-3,
.color-card, .object-item, .install-step, .type-card, .flag-preview,
.flag-steps, .note-banner, .result-preview, .open-question,
.member-card, .toc-card, .app-card, .tool-card, .software-card,
.image-placeholder, .image-placeholder-wide, .detail-text {
  position: relative;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 18px;
  backdrop-filter: blur(10px);
  box-shadow: 0 8px 30px rgba(59, 130, 246, 0.08);
  transform: translateZ(0);
  backface-visibility: hidden;
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  will-change: transform;
}

.task-card::after, .quiz-card::after, .concept-card::after,
.compare-card::after, .mini-card::after, .step-card::after,
.summary-card::after, .zone-card::after, .step-card-3::after,
.color-card::after, .object-item::after, .type-card::after,
.member-card::after, .toc-card::after, .app-card::after,
.tool-card::after, .software-card::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: 0 18px 45px rgba(59, 130, 246, 0.2);
  opacity: 0;
  transition: opacity 0.28s ease;
  pointer-events: none;
  z-index: -1;
}

.task-card:hover, .quiz-card:hover, .concept-card:hover,
.compare-card:hover, .mini-card:hover, .step-card:hover,
.summary-card:hover, .zone-card:hover, .step-card-3:hover,
.color-card:hover, .object-item:hover, .type-card:hover,
.member-card:hover, .toc-card:hover, .app-card:hover,
.tool-card:hover, .software-card:hover {
  transform: translate3d(0, -6px, 0);
}

.task-card:hover::after, .quiz-card:hover::after,
.concept-card:hover::after, .compare-card:hover::after,
.mini-card:hover::after, .step-card:hover::after,
.summary-card:hover::after, .zone-card:hover::after,
.step-card-3:hover::after, .color-card:hover::after,
.object-item:hover::after, .type-card:hover::after,
.member-card:hover::after, .toc-card:hover::after,
.app-card:hover::after, .tool-card:hover::after,
.software-card:hover::after {
  opacity: 1;
}

/* ===== COVER ===== */
.cover-slide {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 50px;
  align-items: center;
}

.badge {
  display: inline-block;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  padding: 8px 18px;
  border-radius: 30px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  backdrop-filter: blur(10px);
}

.badge i { color: var(--blue); margin-right: 6px; }

.main-title {
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 20px;
}

.subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
}

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

.cover-tags { display: flex; gap: 10px; flex-wrap: wrap; }

.cover-tag {
  padding: 8px 16px;
  border-radius: 30px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid var(--card-border);
  font-size: 0.85rem;
  font-weight: 600;
  transform: translateZ(0);
  transition: transform 0.25s ease;
}

.cover-tag:hover { transform: translate3d(0, -3px, 0); }
.cover-tag i { color: var(--blue); margin-right: 6px; }

.cover-right { display: flex; flex-direction: column; gap: 20px; }

.task-card { padding: 22px; }
.card-blue { border-left: 4px solid var(--blue); }
.card-purple { border-left: 4px solid var(--purple); }
.card-emerald { border-left: 4px solid var(--emerald); }
.card-amber { border-left: 4px solid var(--amber); }
.card-rose { border-left: 4px solid var(--rose); }
.card-cyan { border-left: 4px solid var(--cyan); }

.task-icon {
  width: 48px; height: 48px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin-bottom: 12px;
  background: rgba(59, 130, 246, 0.15);
  color: var(--blue);
  transform: translateZ(0);
  animation: iconPulse 3s ease-in-out infinite;
}

@keyframes iconPulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}

.card-purple .task-icon { background: rgba(139, 92, 246, 0.15); color: var(--purple); }
.card-emerald .task-icon { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }

.task-card h3 { font-size: 1.1rem; margin-bottom: 6px; }
.task-card p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.5; }

/* ===== MEMBERS ===== */
.members-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin-bottom: 20px;
}

.members-grid-8 {
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-bottom: 16px;
}

.member-card { padding: 24px 16px; text-align: center; }
.members-grid-8 .member-card { padding: 18px 12px; }

.member-avatar {
  width: 65px; height: 65px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: white;
  margin: 0 auto 14px;
  box-shadow: 0 8px 20px rgba(59, 130, 246, 0.25);
  transform: translateZ(0);
  animation: avatarFloat 4s ease-in-out infinite;
}

.members-grid-8 .member-avatar {
  width: 54px;
  height: 54px;
  font-size: 1.4rem;
  margin-bottom: 10px;
}

@keyframes avatarFloat {
  0%, 100% { transform: translate3d(0, 0, 0); }
  50% { transform: translate3d(0, -8px, 0); }
}

.member-card h3 { font-size: 1rem; margin-bottom: 6px; }
.members-grid-8 .member-card h3 { font-size: 0.92rem; margin-bottom: 5px; }

.member-role {
  display: inline-block;
  padding: 3px 12px;
  border-radius: 20px;
  background: rgba(59, 130, 246, 0.12);
  color: var(--blue);
  font-size: 0.72rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.members-grid-8 .member-role { font-size: 0.68rem; padding: 2px 10px; margin-bottom: 6px; }

.member-task { font-size: 0.8rem; color: var(--text-muted); }
.members-grid-8 .member-task { font-size: 0.75rem; }

.members-note {
  text-align: center;
  font-size: 0.95rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px;
}

.members-note i { color: var(--amber); }

/* ===== TOC ===== */
.toc-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 18px;
}

.toc-card { padding: 28px 22px; position: relative; overflow: hidden; }

.toc-num {
  position: absolute;
  top: 14px; right: 18px;
  font-family: 'Fira Code', monospace;
  font-weight: 700;
  font-size: 2.2rem;
  color: rgba(59, 130, 246, 0.15);
}

.toc-icon {
  width: 58px; height: 58px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 14px;
}

.toc-card.card-blue .toc-icon { background: rgba(59, 130, 246, 0.15); color: var(--blue); }
.toc-card.card-purple .toc-icon { background: rgba(139, 92, 246, 0.15); color: var(--purple); }
.toc-card.card-emerald .toc-icon { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }

.toc-card h3 { font-size: 1.1rem; margin-bottom: 8px; }
.toc-card p { font-size: 0.85rem; color: var(--text-muted); line-height: 1.5; }

.toc-note {
  margin-top: 20px;
  text-align: center;
  font-size: 0.95rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px;
  background: rgba(59, 130, 246, 0.06);
  border-radius: 14px;
}

.toc-note i { color: var(--amber); font-size: 1.15rem; }

/* ===== DETAIL LAYOUT ===== */
.detail-layout {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 24px;
  align-items: stretch;
  margin-bottom: 18px;
}

.detail-text { padding: 24px 26px; }

.detail-lead {
  font-size: 0.98rem;
  line-height: 1.7;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.detail-lead strong { color: var(--text); }

.detail-subtitle { font-size: 1rem; color: var(--blue); margin-bottom: 10px; }

.detail-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 12px;
}

.detail-list li {
  font-size: 0.9rem;
  line-height: 1.55;
  color: var(--text-muted);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.detail-list li i { color: var(--blue); margin-top: 5px; font-size: 0.75rem; flex-shrink: 0; }
.detail-list li b { color: var(--text); }

.detail-note {
  font-size: 0.88rem;
  color: var(--text-muted);
  padding: 10px 14px;
  background: rgba(59, 130, 246, 0.08);
  border-radius: 10px;
}

.detail-note b { color: var(--blue); }

/* ===== IMAGE PLACEHOLDER ===== */
.image-placeholder {
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 10px;
  border: 2px dashed rgba(59, 130, 246, 0.4);
  background: rgba(59, 130, 246, 0.05);
  min-height: 260px;
  border-radius: 18px;
  transform: translateZ(0);
  transition: border-color 0.3s ease;
}

.image-placeholder:hover {
  border-color: var(--blue);
}

.image-placeholder img {
  width: 100%;
  height: 100%;
  max-height: 320px;
  object-fit: contain;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.4);
}

.image-placeholder p {
  font-size: 0.92rem;
  color: var(--text);
  margin-top: 8px;
}

.image-placeholder span {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-style: italic;
}

.image-placeholder-wide {
  padding: 18px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 6px;
  border: 2px dashed rgba(59, 130, 246, 0.4);
  background: rgba(59, 130, 246, 0.05);
  margin-top: 16px;
}

.image-placeholder-wide img {
  width: 100%;
  max-height: 200px;
  object-fit: contain;
  border-radius: 12px;
  margin-bottom: 8px;
}

.image-placeholder-wide p { font-size: 0.9rem; color: var(--text); }
.image-placeholder-wide span { font-size: 0.78rem; color: var(--text-muted); font-style: italic; }

/* ===== APPS / SOFTWARE / TOOLS ===== */
.apps-grid, .software-grid, .tools-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.app-card, .tool-card, .software-card { padding: 20px 18px; text-align: center; }

.app-icon, .tool-icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin: 0 auto 12px;
}

.bg-blue-light { background: rgba(59, 130, 246, 0.15); color: var(--blue); }
.bg-purple-light { background: rgba(139, 92, 246, 0.15); color: var(--purple); }
.bg-emerald-light { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }
.bg-amber-light { background: rgba(245, 158, 11, 0.15); color: var(--amber); }
.bg-rose-light { background: rgba(244, 63, 94, 0.15); color: var(--rose); }
.bg-cyan-light { background: rgba(6, 182, 212, 0.15); color: var(--cyan); }

.app-card h4, .tool-card h4 { font-size: 1rem; margin-bottom: 6px; }
.app-card p, .tool-card p { font-size: 0.82rem; color: var(--text-muted); line-height: 1.4; }

.software-logo {
  width: 56px; height: 56px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: white;
  margin: 0 auto 12px;
}

.software-card h4 { font-size: 1.05rem; margin-bottom: 4px; }

.software-type {
  display: inline-block;
  padding: 3px 12px;
  border-radius: 20px;
  background: rgba(59, 130, 246, 0.12);
  color: var(--blue);
  font-size: 0.72rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.software-desc { font-size: 0.82rem; color: var(--text-muted); line-height: 1.4; }

/* ===== QUIZ ===== */
.quiz-card { padding: 22px 26px; margin-bottom: 14px; }

.question { font-size: 0.95rem; font-weight: 600; margin-bottom: 14px; line-height: 1.55; }
.question i { color: var(--blue); margin-right: 8px; }

.options { display: flex; flex-direction: column; gap: 8px; }

.option {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 10px 14px;
  color: #1e293b;
  font-family: inherit;
  font-size: 0.88rem;
  text-align: left;
  cursor: pointer;
  transition: all 0.25s;
}

.option:hover {
  background: rgba(59, 130, 246, 0.12);
  border-color: var(--blue);
  transform: translateX(6px);
}

.option.correct { background: rgba(16, 185, 129, 0.2); border-color: var(--emerald); }
.option.wrong { background: rgba(244, 63, 94, 0.2); border-color: var(--rose); }

.letter {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  flex-shrink: 0;
  color: var(--blue);
  font-size: 0.85rem;
}

.answer-box {
  display: none;
  margin-top: 14px;
  padding: 12px 16px;
  background: rgba(16, 185, 129, 0.12);
  border-left: 4px solid var(--emerald);
  border-radius: 12px;
  font-size: 0.85rem;
  line-height: 1.55;
}

.answer-box.show { display: flex; gap: 12px; animation: slideDown 0.4s ease; }
.answer-box i { color: var(--emerald); font-size: 1.2rem; margin-top: 2px; }

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== CONCEPT / MINI / TWO TYPES ===== */
.concept-card {
  padding: 24px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
  margin-bottom: 18px;
}

.concept-icon {
  width: 56px; height: 56px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
  color: white;
  animation: iconRotate 6s ease-in-out infinite;
}

@keyframes iconRotate {
  0%, 100% { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(8deg) scale(1.05); }
}

.concept-card p { font-size: 0.95rem; line-height: 1.65; color: var(--text-muted); }
.concept-card strong { color: var(--text); }

.mini-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.mini-card { padding: 20px; text-align: center; }
.mini-card i { font-size: 1.8rem; margin-bottom: 10px; }
.mini-card.card-blue i { color: var(--blue); }
.mini-card.card-purple i { color: var(--purple); }
.mini-card.card-emerald i { color: var(--emerald); }
.mini-card h4 { font-size: 1rem; margin-bottom: 6px; }
.mini-card p { color: var(--text-muted); font-size: 0.82rem; }

.two-types-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.type-card { padding: 24px; text-align: center; }

.type-icon {
  width: 62px; height: 62px;
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  margin: 0 auto 14px;
}

.type-card.bitmap .type-icon { background: rgba(244, 63, 94, 0.15); color: var(--rose); }
.type-card.vector .type-icon { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }

.type-card h3 { font-size: 1.1rem; margin-bottom: 10px; }
.type-card p { color: var(--text-muted); font-size: 0.88rem; line-height: 1.55; margin-bottom: 12px; }
.type-card p b { color: var(--text); }

.type-tag {
  display: inline-block;
  padding: 5px 14px;
  border-radius: 20px;
  background: rgba(59, 130, 246, 0.1);
  color: var(--blue);
  font-size: 0.75rem;
  font-weight: 600;
}

/* ===== COMPARE ===== */
.compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.compare-card { padding: 24px; }
.compare-card.bitmap { border-top: 4px solid var(--rose); }
.compare-card.vector { border-top: 4px solid var(--emerald); }

.compare-icon {
  width: 50px; height: 50px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 14px;
}

.bitmap .compare-icon { background: rgba(244, 63, 94, 0.15); color: var(--rose); }
.vector .compare-icon { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }

.compare-card h3 { font-size: 1.1rem; margin-bottom: 12px; }

.compare-card ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.compare-card li { font-size: 0.85rem; line-height: 1.5; color: var(--text-muted); }
.compare-card li b { color: var(--text); }

/* ===== INKSCAPE MOCKUP ===== */
.inkscape-mockup {
  background: #1e1e2e;
  border: 1px solid var(--card-border);
  border-radius: 18px;
  overflow: hidden;
  margin-bottom: 14px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.mockup-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: #2a2a3e;
}

.dot { width: 12px; height: 12px; border-radius: 50%; }
.dot.red { background: #ff5f57; }
.dot.yellow { background: #febc2e; }
.dot.green { background: #28c840; }

.mockup-title { margin-left: 12px; font-size: 0.85rem; color: #94a3b8; font-family: 'Fira Code', monospace; }

.mockup-body {
  display: grid;
  grid-template-columns: 60px 1fr;
  height: 240px;
}

.mockup-toolbox {
  background: #2a2a3e;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 18px 0;
}

.mockup-toolbox i { color: #94a3b8; font-size: 1.15rem; cursor: pointer; transition: color 0.2s; }
.mockup-toolbox i:hover { color: #60a5fa; }

.mockup-canvas {
  position: relative;
  background: #f8fafc;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
}

.canvas-label {
  position: absolute;
  top: 12px; left: 16px;
  font-size: 0.8rem;
  color: #64748b;
  font-family: 'Fira Code', monospace;
}

.canvas-shape.circle {
  width: 70px; height: 70px;
  border-radius: 50%;
  background: linear-gradient(135deg, #3b82f6, #8b5cf6);
  animation: canvasSpin 6s ease-in-out infinite;
}

.canvas-shape.square {
  width: 70px; height: 70px;
  background: linear-gradient(135deg, #10b981, #34d399);
  border-radius: 12px;
  animation: canvasSpin 6s ease-in-out infinite 0.5s;
}

.canvas-shape.star {
  font-size: 4rem;
  color: #f59e0b;
  animation: canvasSpin 6s ease-in-out infinite 1s;
}

@keyframes canvasSpin {
  0%, 100% { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(10deg) scale(1.05); }
}

.legend {
  display: flex;
  justify-content: center;
  gap: 26px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.legend i { margin-right: 6px; }

/* ===== ZONES ===== */
.zones-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.zone-card { padding: 20px; text-align: center; }
.zone-card i { font-size: 1.7rem; margin-bottom: 10px; display: block; }
.zone-card.card-blue i { color: var(--blue); }
.zone-card.card-purple i { color: var(--purple); }
.zone-card.card-emerald i { color: var(--emerald); }
.zone-card.card-amber i { color: var(--amber); }
.zone-card.card-rose i { color: var(--rose); }
.zone-card.card-cyan i { color: var(--cyan); }
.zone-card h4 { font-size: 0.98rem; margin-bottom: 6px; }
.zone-card p { color: var(--text-muted); font-size: 0.82rem; line-height: 1.4; }

/* ===== INSTALL STEPS ===== */
.install-steps { display: flex; flex-direction: column; gap: 12px; }

.install-step {
  padding: 18px 22px;
  display: flex;
  align-items: center;
  gap: 16px;
}

.step-circle {
  width: 40px; height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
}

.step-content h4 { font-size: 0.98rem; margin-bottom: 3px; }
.step-content p { font-size: 0.86rem; color: var(--text-muted); line-height: 1.45; }
.step-content b { color: var(--text); }

/* ===== OBJECT GRID ===== */
.object-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 12px;
}

.object-item {
  padding: 16px 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.object-item i { font-size: 1.5rem; color: var(--blue); }
.object-item span { font-size: 0.82rem; font-weight: 600; }

/* ===== STEPS 3 & 4 ===== */
.steps-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-bottom: 14px;
}

.step-card-3 { padding: 26px 20px; text-align: center; position: relative; }

.step-num-3 {
  position: absolute;
  top: -14px; left: 50%;
  transform: translateX(-50%);
  width: 30px; height: 30px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.step-icon-3 { font-size: 1.8rem; color: var(--blue); margin: 14px 0; }
.step-card-3 h4 { font-size: 1rem; margin-bottom: 6px; }
.step-card-3 p { font-size: 0.86rem; color: var(--text-muted); line-height: 1.45; }

.steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-bottom: 16px;
}

.step-card { padding: 20px 14px; text-align: center; position: relative; }

.step-num {
  position: absolute;
  top: -12px; left: 50%;
  transform: translateX(-50%);
  width: 26px; height: 26px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8rem;
}

.step-visual { margin: 12px 0 10px; }
.step-card p { font-size: 0.82rem; color: var(--text-muted); line-height: 1.4; }

.result-preview {
  padding: 20px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.result-preview p { color: var(--text-muted); font-size: 0.92rem; }
.result-preview strong { color: var(--text); }

/* ===== FLAG ===== */
.flag-practice {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 22px;
}

.flag-preview {
  padding: 26px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

.flag-red {
  width: 200px; height: 133px;
  background: #da251d;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  box-shadow: 0 10px 30px rgba(218, 37, 29, 0.25);
  animation: flagWave 3s ease-in-out infinite;
}

@keyframes flagWave {
  0%, 100% { transform: rotate(-1deg); }
  50% { transform: rotate(1deg); }
}

.flag-red i {
  font-size: 3.5rem;
  color: #ffff00;
  animation: starSpin 6s linear infinite;
}

@keyframes starSpin {
  0%, 100% { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(5deg) scale(1.05); }
}

.flag-preview p { font-size: 0.88rem; color: var(--text-muted); }
.flag-steps { padding: 24px; }
.flag-steps h4 { font-size: 1rem; margin-bottom: 12px; color: var(--blue); }
.flag-steps ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.flag-steps li { font-size: 0.86rem; color: var(--text-muted); line-height: 1.5; }
.flag-steps li b { color: var(--text); }

/* ===== COLOR INFO ===== */
.color-info-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-bottom: 16px;
}

.color-card { padding: 22px; text-align: center; }

.color-demo {
  width: 90px; height: 90px;
  border-radius: 16px;
  margin: 0 auto 14px;
  animation: colorFloat 4s ease-in-out infinite;
}

@keyframes colorFloat {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-8px) rotate(4deg); }
}

.fill-demo { background: linear-gradient(135deg, #60a5fa, #a78bfa); }
.stroke-demo { background: transparent; border: 6px solid #f43f5e; }

.color-card h4 { font-size: 1rem; margin-bottom: 8px; }
.color-card p { font-size: 0.86rem; color: var(--text-muted); margin-bottom: 12px; }

.color-card code {
  display: inline-block;
  padding: 5px 14px;
  background: rgba(59, 130, 246, 0.1);
  color: var(--blue);
  border-radius: 20px;
  font-size: 0.78rem;
  font-family: 'Fira Code', monospace;
}

.note-banner {
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(245, 158, 11, 0.12);
  border-left: 4px solid var(--amber);
}

.note-banner i { color: var(--amber); font-size: 1.2rem; }
.note-banner span { font-size: 0.9rem; line-height: 1.5; }

/* ===== TF ===== */
.tf-list { display: flex; flex-direction: column; gap: 12px; }

.tf-item { padding: 18px 22px; }
.tf-item p { font-size: 0.92rem; margin-bottom: 12px; line-height: 1.55; }

.tf-buttons { display: flex; gap: 12px; }

.tf-btn {
  padding: 8px 22px;
  border-radius: 10px;
  border: 1px solid rgba(148, 163, 184, 0.4);
  background: rgba(255, 255, 255, 0.7);
  color: #1e293b;
  font-family: inherit;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.tf-btn:hover { background: rgba(59, 130, 246, 0.15); border-color: var(--blue); }
.tf-btn.correct { background: rgba(16, 185, 129, 0.25); border-color: var(--emerald); }
.tf-btn.wrong { background: rgba(244, 63, 94, 0.25); border-color: var(--rose); }

.tf-feedback {
  display: none;
  margin-top: 10px;
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.5);
  border-radius: 10px;
  font-size: 0.82rem;
  line-height: 1.55;
}

.tf-feedback.show { display: block; animation: slideDown 0.4s ease; }

/* ===== OPEN QUESTION ===== */
.open-question { padding: 20px 24px; }
.open-question p { font-size: 0.95rem; margin-bottom: 12px; line-height: 1.55; font-weight: 600; }

.open-answer {
  display: flex;
  gap: 12px;
  padding: 14px 18px;
  background: rgba(245, 158, 11, 0.1);
  border-left: 4px solid var(--amber);
  border-radius: 10px;
  font-size: 0.86rem;
  line-height: 1.55;
}

.open-answer i { color: var(--amber); font-size: 1.15rem; margin-top: 2px; }

/* ===== SUMMARY ===== */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-bottom: 22px;
}

.summary-card { padding: 24px 20px; text-align: center; }

.summary-icon {
  width: 58px; height: 58px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin: 0 auto 14px;
}

.summary-card.card-blue .summary-icon { background: rgba(59, 130, 246, 0.15); color: var(--blue); }
.summary-card.card-purple .summary-icon { background: rgba(139, 92, 246, 0.15); color: var(--purple); }
.summary-card.card-emerald .summary-icon { background: rgba(16, 185, 129, 0.15); color: var(--emerald); }

.summary-card h3 { font-size: 1.05rem; margin-bottom: 10px; }
.summary-card p { font-size: 0.85rem; color: var(--text-muted); line-height: 1.55; }
.summary-card p b { color: var(--text); }

.thanks {
  text-align: center;
  font-size: 1rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px;
  animation: heartBeat 2s ease-in-out infinite;
}

@keyframes heartBeat {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

/* ===== EDGE NAV ===== */
.edge-nav {
  position: fixed;
  top: 0; bottom: 0;
  width: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: #3b82f6;
  cursor: pointer;
  z-index: 90;
  opacity: 0;
  transition: opacity 0.3s ease, background 0.3s ease;
  user-select: none;
}

.edge-nav-left { left: 0; }
.edge-nav-right { right: 0; }

.edge-nav:hover {
  opacity: 1;
  background: linear-gradient(to right, rgba(59, 130, 246, 0.18), transparent);
}

.edge-nav-right:hover {
  background: linear-gradient(to left, rgba(139, 92, 246, 0.18), transparent);
}

.edge-nav i {
  background: rgba(255, 255, 255, 0.9);
  width: 48px; height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.25);
  backdrop-filter: blur(10px);
  transition: transform 0.25s ease;
}

.edge-nav:hover i { transform: scale(1.15); }

/* ===== RESPONSIVE ===== */
@media (max-width: 1366px) and (max-height: 768px) {
  .slide { padding: 40px 30px; }
  .slide-header { margin-bottom: 16px; }
  .slide-header h2 { font-size: clamp(1.3rem, 2.2vw, 1.7rem); }
  .main-title { font-size: clamp(1.6rem, 3.2vw, 2.4rem); }
  .subtitle { font-size: 0.95rem; }
  .quiz-card, .concept-card, .detail-text { padding: 18px 22px; }
  .task-card, .mini-card, .app-card, .tool-card,
  .software-card, .zone-card, .summary-card { padding: 16px; }
  .flag-red { width: 170px; height: 113px; }
  .flag-red i { font-size: 3rem; }
}

@media (min-width: 1601px) {
  .slide-content { max-width: 1500px; }
  .slide { padding: 70px 80px; }
  .slide-header h2 { font-size: 2.6rem; }
  .main-title { font-size: 4rem; }
  .subtitle { font-size: 1.3rem; }
  .quiz-card, .concept-card, .detail-text { padding: 34px 40px; }
  .task-card, .mini-card, .app-card, .tool-card,
  .software-card, .zone-card, .summary-card { padding: 28px; }
  .member-avatar { width: 85px; height: 85px; font-size: 2rem; }
  .member-card h3 { font-size: 1.3rem; }
  .toc-card h3 { font-size: 1.4rem; }
  .app-card h4, .tool-card h4, .software-card h4 { font-size: 1.15rem; }
  .step-card, .step-card-3 { padding: 30px 22px; }
  .step-card-3 h4 { font-size: 1.2rem; }
  .step-card-3 p { font-size: 1rem; }
  .flag-red { width: 280px; height: 187px; }
  .flag-red i { font-size: 5rem; }
  .slide-counter { font-size: 1.05rem; padding: 10px 20px; }
  .edge-nav i { width: 60px; height: 60px; font-size: 1.8rem; }
  .members-grid-8 { gap: 20px; }
  .members-grid-8 .member-card { padding: 24px 18px; }
  .members-grid-8 .member-avatar { width: 70px; height: 70px; font-size: 1.7rem; }
  .members-grid-8 .member-card h3 { font-size: 1.15rem; }
  .members-grid-8 .member-role { font-size: 0.82rem; }
  .members-grid-8 .member-task { font-size: 0.92rem; }
}

@media (max-width: 900px) {
  .cover-slide, .compare-grid, .two-types-grid, .zones-grid,
  .mini-grid, .summary-grid, .color-info-grid, .flag-practice,
  .members-grid, .members-grid-8, .toc-grid, .detail-layout,
  .apps-grid, .software-grid, .tools-grid {
    grid-template-columns: 1fr;
  }
  .members-grid-8 { grid-template-columns: repeat(2, 1fr); }
  .steps-grid { grid-template-columns: repeat(2, 1fr); }
  .steps-grid-3 { grid-template-columns: 1fr; }
  .object-grid { grid-template-columns: repeat(3, 1fr); }
  .slide { padding: 70px 20px 90px; }
  .slide-counter { top: 12px; right: 12px; }
  .edge-nav { width: 60px; }
}