/* ── Curriculum Download Banner ───────────────────────────────────────────── */
.curriculum-download-section {
  padding: var(--space-6) 70px;
  margin-bottom: var(--space-8);
  width: 100%;
  display: flex;
  justify-content: center;
}

.curriculum-download-container {
  background: linear-gradient(135deg, #1a1a1a 0%, #131313 100%);
  border: 1px solid rgba(229, 57, 53, 0.3);
  border-radius: var(--radius-xl);
  padding: var(--space-4) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.4);
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  position: relative;
  overflow: hidden;
}

.curriculum-download-container::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 4px;
  background: var(--color-brand-red);
}

.curriculum-content {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding-left: var(--space-2);
}

.curriculum-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.curriculum-icon img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.curriculum-text h3 {
  font-family: "Switzer", sans-serif;
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 2px 0;
  color: var(--color-text-primary);
  letter-spacing: -0.015em;
}

.curriculum-text p {
  font-family: "Inter", sans-serif;
  font-size: 0.92rem;
  color: var(--color-text-secondary);
  margin: 0;
}

.curriculum-download-container .btn-download {
  background: var(--color-brand-red);
  color: #ffffff;
  border: none;
  padding: 12px 28px;
  border-radius: var(--radius-pill);
  font-family: "Inter", sans-serif;
  font-weight: 600;
  font-size: 0.92rem;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.2s ease;
  white-space: nowrap;
  flex-shrink: 0;
  box-shadow: 0 4px 14px rgba(229, 57, 53, 0.35);
  cursor: pointer;
}

.curriculum-download-container .btn-download:hover {
  background: #cc2a25;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(229, 57, 53, 0.5);
  color: #ffffff;
}

.curriculum-download-container .btn-download:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}

@media (max-width: 992px) {
  .curriculum-download-section {
    padding: var(--space-4) 30px;
    margin-bottom: var(--space-6);
  }
  .curriculum-download-container {
    padding: var(--space-4);
    gap: var(--space-3);
  }
  .curriculum-text h3 {
    font-size: 1.05rem;
  }
  .curriculum-text p {
    font-size: 0.82rem;
  }
  .curriculum-download-container .btn-download {
    padding: 10px 18px;
    font-size: 0.85rem;
  }
}

@media (max-width: 768px) {
  .curriculum-download-section {
    padding: var(--space-4) 16px;
    margin-bottom: var(--space-4);
  }
  .curriculum-download-container {
    padding: 12px 14px;
    gap: 12px;
  }
  .curriculum-icon {
    width: 28px;
    height: 28px;
  }
  .curriculum-text h3 {
    font-size: 0.95rem;
  }
  .curriculum-text p {
    font-size: 0.76rem;
  }
  .curriculum-download-container .btn-download {
    padding: 8px 16px;
    font-size: 0.80rem;
  }
}

@media (max-width: 576px) {
  .curriculum-download-container {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding: 12px 14px;
  }
  .curriculum-text h3 {
    font-size: 0.90rem;
  }
  .curriculum-text p {
    font-size: 0.74rem;
  }
  .curriculum-download-container .btn-download {
    width: 100%;
    justify-content: center;
    padding: 8px 14px;
    font-size: 0.78rem;
  }
}

/* ── 2-Semester / 8-Paper Curriculum Explorer ────────────────────────────── */
.curriculum-explorer-section {
  position: relative;
}

.curriculum-header {
  margin-bottom: var(--space-8);
}

/* Semester Switcher Tabs */
.semester-tabs-container {
  width: 100%;
  margin-bottom: var(--space-6);
}

.semester-tabs-nav {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  background: #111114;
  padding: 10px;
  border-radius: 18px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: inset 0 2px 8px rgba(0, 0, 0, 0.7);
}

.semester-tab-btn {
  position: relative;
  background: linear-gradient(180deg, #1f1f24 0%, #161619 100%);
  border: 1.5px solid rgba(255, 255, 255, 0.12);
  border-radius: 14px;
  padding: 18px 22px;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 8px;
  cursor: pointer;
  transition: all 0.22s cubic-bezier(0.16, 1, 0.3, 1);
  color: var(--color-text-secondary);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.1);
  user-select: none;
}

/* Distinct clickable hover on inactive button */
.semester-tab-btn:hover:not(.active) {
  background: linear-gradient(180deg, #2a2a33 0%, #1c1c22 100%);
  border-color: rgba(255, 255, 255, 0.35);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.6), 0 0 16px rgba(255, 255, 255, 0.06), inset 0 1px 0 rgba(255, 255, 255, 0.25);
  color: #ffffff;
}

.semester-tab-btn:hover:not(.active) .sem-tab-title {
  color: #ffffff;
}

.semester-tab-btn:hover:not(.active) .chip-inactive {
  background: rgba(255, 255, 255, 0.18);
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.4);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
  transform: translateX(3px);
}

.semester-tab-btn:hover:not(.active) .chip-inactive i {
  transform: translateX(2px);
}

/* Click / Active press feedback */
.semester-tab-btn:active {
  transform: translateY(1px) scale(0.992);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.6), inset 0 1px 2px rgba(0, 0, 0, 0.4);
  transition-duration: 0.08s;
}

/* Selected active button */
.semester-tab-btn.active {
  background: linear-gradient(180deg, rgba(239, 68, 68, 0.18) 0%, #181414 100%);
  border: 1.5px solid #ff3b30;
  color: #ffffff;
  box-shadow: 0 0 0 1px rgba(255, 59, 48, 0.45), 0 8px 26px rgba(239, 68, 68, 0.22), inset 0 1px 0 rgba(255, 255, 255, 0.2);
  transform: translateY(0);
}

.semester-tab-btn.active .sem-tab-title {
  color: #ffffff;
}

.semester-tab-btn:focus-visible {
  outline: 2px solid #ff3333;
  outline-offset: 2px;
}

.sem-tab-top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.sem-tab-badge {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--color-brand-red);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.sem-tab-badge::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
}

.sem-tab-state-chip {
  display: inline-flex;
  align-items: center;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.chip-active {
  display: none;
  align-items: center;
  gap: 6px;
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.28) 0%, rgba(220, 38, 38, 0.15) 100%);
  color: #ff6b6b;
  border: 1px solid rgba(255, 82, 82, 0.55);
  border-radius: 20px;
  padding: 3px 12px;
  box-shadow: 0 0 10px rgba(239, 68, 68, 0.25);
}

.chip-inactive {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.09);
  color: #e2e8f0;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 20px;
  padding: 3px 12px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.25);
  transition: all 0.2s ease;
}

.chip-inactive i {
  transition: transform 0.2s ease;
}

.semester-tab-btn.active .chip-active {
  display: inline-flex;
}

.semester-tab-btn.active .chip-inactive {
  display: none;
}

.sem-tab-title {
  font-family: "Switzer", sans-serif;
  font-size: 1.05rem;
  font-weight: 600;
  color: #e2e8f0;
  line-height: 1.35;
  transition: color 0.2s;
}

.sem-tab-duration {
  font-size: 0.8rem;
  color: #94a3b8;
  display: flex;
  align-items: center;
  gap: 6px;
}

.sem-tab-duration i {
  margin-right: 0 !important;
}

.semester-tab-btn.active .sem-tab-duration {
  color: rgba(255, 255, 255, 0.75);
}

/* Panels */
.semester-content-panel {
  display: none;
  animation: fadeInPanel 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.semester-content-panel.active {
  display: block;
}

@keyframes fadeInPanel {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.semester-meta-intro {
  margin-bottom: var(--space-6);
}

.sem-intro-desc {
  background: var(--color-surface-card);
  border-left: 3px solid var(--color-brand-red);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 12px 18px;
  font-size: 0.92rem;
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.55;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  border-top: 1px solid var(--color-border-subtle);
  border-right: 1px solid var(--color-border-subtle);
  border-bottom: 1px solid var(--color-border-subtle);
}

.sem-intro-desc i {
  margin-top: 3px;
  flex-shrink: 0;
  margin-right: 0 !important;
}

/* Papers Grid */
.papers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.paper-card {
  background: var(--color-surface-card);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), 
              border-color 0.2s ease, 
              box-shadow 0.2s ease;
  position: relative;
}

.paper-card:hover {
  transform: translateY(-2px);
  border-color: var(--color-border-hover);
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.4);
}

.paper-highlight-ai {
  background: linear-gradient(145deg, #171424 0%, #121216 100%);
  border: 1px solid rgba(168, 85, 247, 0.3);
  box-shadow: 0 0 20px rgba(168, 85, 247, 0.08);
}

.paper-highlight-ai:hover {
  border-color: rgba(168, 85, 247, 0.5);
  box-shadow: 0 12px 30px rgba(168, 85, 247, 0.15);
}

.paper-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-3);
}

.paper-number-tag {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-brand-red);
  background: rgba(229, 57, 53, 0.1);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
}

.paper-highlight-ai .paper-number-tag {
  color: #c084fc;
  background: rgba(168, 85, 247, 0.15);
}

.paper-badge {
  font-size: 0.72rem;
  font-weight: 600;
  background: rgba(255, 255, 255, 0.06);
  color: var(--color-text-secondary);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
}

.ai-badge {
  background: linear-gradient(90deg, #9333ea, #6366f1);
  color: #ffffff !important;
  font-weight: 600;
}

.paper-title {
  font-family: "Switzer", sans-serif;
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-top: 0;
  margin-bottom: var(--space-1);
  letter-spacing: -0.01em;
}

.paper-subtitle {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 0;
  margin-bottom: var(--space-4);
  line-height: 1.4;
}

.paper-items-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.paper-items-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.paper-item-bullet {
  flex-shrink: 0;
  margin-top: 3px;
}

/* Mobile responsive */
@media (max-width: 992px) {
  .semester-tabs-nav {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }
  .papers-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }
  .paper-card {
    padding: var(--space-4);
  }
}

@media (max-width: 768px) {
  .semester-tabs-nav {
    grid-template-columns: 1fr;
    gap: 6px;
    padding: 6px;
  }
  .semester-tab-btn {
    padding: 10px 14px;
    border-radius: 10px;
    gap: 4px;
  }
  .sem-tab-badge {
    font-size: 0.66rem;
    padding: 2px 7px;
  }
  .sem-tab-title {
    font-size: 0.95rem;
  }
  .sem-tab-duration {
    font-size: 0.74rem;
  }
  .papers-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .paper-card {
    padding: 14px 14px;
    border-radius: 12px;
  }
  .paper-num-badge {
    font-size: 0.66rem;
    padding: 2px 6px;
  }
  .paper-title {
    font-size: 1.02rem;
    margin-bottom: 2px;
  }
  .paper-subtitle {
    font-size: 0.76rem;
    margin-bottom: 10px;
  }
  .paper-items-list {
    gap: 6px;
  }
  .paper-items-list li {
    font-size: 0.80rem;
    line-height: 1.45;
    gap: 8px;
  }
  .paper-item-bullet svg {
    width: 14px;
    height: 14px;
  }
  .skill-list li,
  .skill-item {
    padding: 10px 14px;
    gap: 10px;
    border-radius: 10px;
  }
  .skill-item-text {
    font-size: 0.82rem;
  }
  .skill-item-bullet {
    width: 22px;
    height: 22px;
  }
  .skill-item-bullet img,
  .skill-list li img {
    width: 11px;
    height: 11px;
  }
}

@media (max-width: 576px) {
  .paper-card {
    padding: 12px 12px;
  }
  .paper-title {
    font-size: 0.94rem;
  }
  .paper-items-list li {
    font-size: 0.76rem;
  }
  .semester-tab-btn {
    padding: 8px 12px;
  }
  .sem-tab-title {
    font-size: 0.88rem;
  }
}

/* ── Classic Skills Fallback (Enterprise UI/UX Redesign) ─────────────────── */
.classic-skills-container {
  margin-top: var(--space-2);
}

.skill-list {
  list-style: none !important;
  list-style-type: none !important;
  padding: 0 !important;
  margin: 0 !important;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.skill-list li,
.skill-item {
  list-style: none !important;
  list-style-type: none !important;
  background: var(--color-surface-card);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: 14px 18px;
  display: flex;
  align-items: center;
  gap: 14px;
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1),
              border-color 0.2s ease,
              background 0.2s ease,
              box-shadow 0.2s ease;
}

.skill-list li:hover,
.skill-item:hover {
  background: var(--color-surface-elevated);
  border-color: rgba(229, 57, 53, 0.35);
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

.skill-item-bullet {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background: rgba(229, 57, 53, 0.1);
  border: 1px solid rgba(229, 57, 53, 0.15);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.skill-item-bullet img,
.skill-list li img {
  width: 14px;
  height: 14px;
  object-fit: contain;
}

.skill-item-text {
  font-family: "Switzer", "Inter", sans-serif;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-primary);
  line-height: 1.45;
}