/* ==========================================================================
   IELTS Speaking Phrases & Grammar Studio Stylesheet
   Design System: English Mastery Hub - 3-Tier Band Progression
   ========================================================================== */

/* Gradient & Brand Accents */
.gradient-text-brand {
  background: linear-gradient(135deg, #7c3aed 0%, #4f46e5 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.gradient-text-grammar {
  background: linear-gradient(135deg, #0ea5e9 0%, #6366f1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.phrase-card {
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.2s ease, border-color 0.2s ease;
}

.phrase-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px -6px rgba(124, 58, 237, 0.12), 0 4px 10px -2px rgba(0, 0, 0, 0.04);
}

.dark .phrase-card:hover {
  box-shadow: 0 12px 28px -6px rgba(0, 0, 0, 0.4), 0 4px 12px rgba(124, 58, 237, 0.16);
}

/* 3-Tier Progression Stepper Cards */
.tier-progression-stack {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  position: relative;
}

/* Tier 1: Band 5.0 (Mistakes & Traps) */
.band-tier-5 {
  background: #fff1f2;
  border: 1px dashed #fda4af;
  border-radius: 0.875rem;
  padding: 0.85rem 1rem;
  position: relative;
}

.dark .band-tier-5 {
  background: rgba(159, 18, 57, 0.12);
  border-color: rgba(251, 113, 133, 0.35);
}

/* Tier 2: Bands 6.0–7.0 (Competent Baseline) */
.band-tier-6-7 {
  background: #f8fafc;
  border: 1px solid #cbd5e1;
  border-radius: 0.875rem;
  padding: 0.85rem 1rem;
  position: relative;
}

.dark .band-tier-6-7 {
  background: rgba(30, 41, 59, 0.5);
  border-color: rgba(100, 116, 139, 0.4);
}

/* Tier 3: Band 7.5+ (High-Band Mastery) */
.band-tier-75 {
  background: #f0fdf4;
  border: 1.5px solid #4ade80;
  border-radius: 0.875rem;
  padding: 0.95rem 1.05rem;
  position: relative;
  box-shadow: 0 2px 8px rgba(34, 197, 94, 0.06);
}

.dark .band-tier-75 {
  background: rgba(20, 83, 45, 0.22);
  border-color: rgba(74, 222, 128, 0.4);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

/* Audio Pulse State */
.audio-playing-btn {
  background-color: #ef4444 !important;
  color: #ffffff !important;
  box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.25) !important;
  animation: audioPulse 1.6s infinite ease-in-out;
}

@keyframes audioPulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.06); }
  100% { transform: scale(1); }
}

/* Grammatical Formula Syntax Tag */
.formula-box {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 0.875rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  position: relative;
  overflow: hidden;
}

.dark .formula-box {
  background: #090d16;
  border-color: #1e293b;
}

.formula-token-main {
  color: #7c3aed;
  font-weight: 800;
}
.dark .formula-token-main {
  color: #a78bfa;
}

.formula-token-var {
  color: #0284c7;
  font-weight: 600;
  background: rgba(14, 165, 233, 0.1);
  padding: 0.1rem 0.35rem;
  border-radius: 0.35rem;
}
.dark .formula-token-var {
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.15);
}

.formula-token-sub {
  color: #d97706;
  font-weight: 600;
  background: rgba(245, 158, 11, 0.1);
  padding: 0.1rem 0.35rem;
  border-radius: 0.35rem;
}
.dark .formula-token-sub {
  color: #fbbf24;
  background: rgba(251, 191, 36, 0.15);
}

/* Bookmark Star Animation */
.btn-bookmark {
  transition: transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275), color 0.15s ease;
}

.btn-bookmark:hover {
  transform: scale(1.18);
}

.btn-bookmark.bookmarked {
  color: #f59e0b;
}

/* Custom Scrollbar for Drawer & Menus */
.custom-scrollbar::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
.custom-scrollbar::-webkit-scrollbar-track {
  background: transparent;
}
.custom-scrollbar::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 4px;
}
.dark .custom-scrollbar::-webkit-scrollbar-thumb {
  background: #334155;
}