/* ═════════════════════════════════════════════════════════════════════
   STUDYRIA UI/UX 2.0 — SAFE VISUAL UPGRADE (v2.0.2)
   NO opacity/visibility changes on any page or section.
   Only hover effects, transitions, typography, shadows.
   ═════════════════════════════════════════════════════════════════════ */

/* ══ TOKENS ══════════════════════════════════════════════════════════ */
:root {
  --ui2-shadow-sm:  0 2px 8px rgba(0,0,0,0.08);
  --ui2-shadow-md:  0 4px 16px rgba(0,0,0,0.12);
  --ui2-shadow-lg:  0 12px 40px rgba(0,0,0,0.18);
  --ui2-shadow-xl:  0 24px 60px rgba(0,0,0,0.22);
  --ui2-ease:       cubic-bezier(0.22, 1, 0.36, 1);
  --ui2-bounce:     cubic-bezier(0.34, 1.56, 0.64, 1);
  --ui2-dur:        0.22s;
}

/* ══ TYPOGRAPHY ══════════════════════════════════════════════════════ */
body {
  -webkit-font-smoothing: antialiased !important;
  -moz-osx-font-smoothing: grayscale !important;
  text-rendering: optimizeLegibility !important;
}

h1, h2, h3, h4, h5, h6 {
  letter-spacing: -0.022em !important;
}

.stat-num { letter-spacing: -0.03em !important; }
.section-title { letter-spacing: -0.022em !important; }

/* ══ SCROLLBAR ═══════════════════════════════════════════════════════ */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, var(--accent, #3d8ef8), var(--accent2, #00c8e8));
  border-radius: 10px;
}

/* ══ CARDS — hover lift only ═════════════════════════════════════════ */
.pdf-card {
  border-radius: 16px !important;
  transition: transform var(--ui2-dur) var(--ui2-ease),
              box-shadow var(--ui2-dur) var(--ui2-ease),
              border-color var(--ui2-dur) var(--ui2-ease) !important;
}
.pdf-card:hover {
  transform: translateY(-5px) !important;
  box-shadow: var(--ui2-shadow-lg) !important;
}

.ottlib-card {
  border-radius: 16px !important;
  transition: transform var(--ui2-dur) var(--ui2-ease),
              box-shadow var(--ui2-dur) var(--ui2-ease) !important;
}
.ottlib-card:hover {
  transform: translateY(-5px) !important;
  box-shadow: var(--ui2-shadow-lg) !important;
}

.card {
  border-radius: 20px !important;
  transition: transform var(--ui2-dur) var(--ui2-ease),
              box-shadow var(--ui2-dur) var(--ui2-ease),
              border-color var(--ui2-dur) var(--ui2-ease) !important;
}
.card:hover {
  transform: translateY(-4px) !important;
  box-shadow: var(--ui2-shadow-xl) !important;
  border-color: rgba(61,142,248,0.25) !important;
}

.stat-card {
  border-radius: 20px !important;
  transition: transform var(--ui2-dur) var(--ui2-ease),
              box-shadow var(--ui2-dur) var(--ui2-ease) !important;
}
.stat-card:hover {
  transform: translateY(-3px) !important;
  box-shadow: var(--ui2-shadow-md) !important;
}

/* ══ BUTTONS ══════════════════════════════════════════════════════════ */
.btn,
.sh-btn {
  transition: transform var(--ui2-dur) var(--ui2-bounce),
              box-shadow var(--ui2-dur) var(--ui2-ease),
              filter var(--ui2-dur) var(--ui2-ease),
              background var(--ui2-dur) var(--ui2-ease) !important;
}

.btn-primary,
.sh-btn-primary {
  box-shadow: 0 4px 14px rgba(61,142,248,0.22) !important;
}
.btn-primary:hover,
.sh-btn-primary:hover {
  box-shadow: 0 8px 24px rgba(61,142,248,0.32) !important;
  transform: translateY(-2px) !important;
}

.btn:active, .sh-btn:active {
  transform: scale(0.97) !important;
}

.btn-secondary, .sh-btn-secondary {
  backdrop-filter: blur(12px) !important;
  -webkit-backdrop-filter: blur(12px) !important;
}

/* ══ INPUTS ══════════════════════════════════════════════════════════ */
input, textarea, select {
  transition: border-color var(--ui2-dur) var(--ui2-ease),
              box-shadow var(--ui2-dur) var(--ui2-ease) !important;
}
input:focus, textarea:focus {
  outline: none !important;
  box-shadow: 0 0 0 3px rgba(61,142,248,0.12) !important;
}

/* ══ NAV LINK UNDERLINE ══════════════════════════════════════════════ */
.nav-link {
  position: relative;
  transition: color var(--ui2-dur) var(--ui2-ease),
              background var(--ui2-dur) var(--ui2-ease) !important;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: 2px; left: 50%;
  width: 0; height: 2px;
  background: linear-gradient(90deg, var(--accent, #3d8ef8), var(--accent2, #00c8e8));
  border-radius: 2px;
  transition: width var(--ui2-dur) var(--ui2-ease),
              left var(--ui2-dur) var(--ui2-ease);
}
.nav-link.active::after { width: 60%; left: 20%; }

/* ══ MOBILE NAV ══════════════════════════════════════════════════════ */
.mobile-nav-item {
  transition: transform 0.12s var(--ui2-ease), color var(--ui2-dur) var(--ui2-ease) !important;
}
.mobile-nav-item:active { transform: scale(0.9) !important; }

/* ══ LIBRARY ══════════════════════════════════════════════════════════ */
.ottlib-hero { border-radius: 0 0 28px 28px; }

.ottlib-stat {
  border-radius: 14px !important;
  transition: transform var(--ui2-dur) var(--ui2-ease),
              border-color var(--ui2-dur) var(--ui2-ease) !important;
}
.ottlib-stat:hover {
  transform: translateY(-2px) !important;
  border-color: rgba(61,142,248,0.25) !important;
}
.ottlib-stat-num { font-weight: 800 !important; letter-spacing: -0.02em !important; }

.ottlib-search-input {
  border-radius: 14px !important;
  transition: all var(--ui2-dur) var(--ui2-ease) !important;
}
.ottlib-search-input:focus {
  box-shadow: 0 0 0 3px rgba(61,142,248,0.12) !important;
}

.ottlib-cat-pill {
  border-radius: 100px !important;
  transition: all var(--ui2-dur) var(--ui2-bounce) !important;
}
.ottlib-cat-pill:hover { transform: translateY(-2px) !important; }
.ottlib-cat-pill.active { box-shadow: 0 4px 12px rgba(61,142,248,0.22) !important; }

/* ══ PREMIUM PAGE ════════════════════════════════════════════════════ */
#page-premium .prm-plan-card {
  transition: transform var(--ui2-dur) var(--ui2-bounce),
              box-shadow var(--ui2-dur) var(--ui2-ease),
              border-color var(--ui2-dur) var(--ui2-ease) !important;
}
#page-premium .prm-plan-card:hover {
  transform: translateY(-8px) scale(1.02) !important;
  box-shadow: 0 28px 60px rgba(0,0,0,0.38) !important;
}

/* ══ MENU BACKDROP ═══════════════════════════════════════════════════ */
#hamburgerMenu {
  backdrop-filter: blur(20px) saturate(160%) !important;
  -webkit-backdrop-filter: blur(20px) saturate(160%) !important;
}

/* ══ SELECTION ═══════════════════════════════════════════════════════ */
::selection {
  background: rgba(61,142,248,0.22);
  color: var(--text, #eef2ff);
}

/* ══ FOCUS RING ══════════════════════════════════════════════════════ */
*:focus-visible {
  outline: 2px solid var(--accent, #3d8ef8) !important;
  outline-offset: 3px !important;
  border-radius: 4px !important;
}

/* ══ HR ══════════════════════════════════════════════════════════════ */
hr {
  border: none !important;
  height: 1px !important;
  background: linear-gradient(90deg, transparent,
    var(--glass-border, rgba(255,255,255,0.09)), transparent) !important;
}

/* ══ SKELETON UTILITY (opt-in via class) ═════════════════════════════ */
.ui2-skeleton {
  background: linear-gradient(90deg,
    rgba(255,255,255,0.04) 0%,
    rgba(255,255,255,0.09) 50%,
    rgba(255,255,255,0.04) 100%);
  background-size: 200% 100%;
  animation: ui2Shimmer 1.6s infinite linear;
  border-radius: 12px;
}
body.light .ui2-skeleton {
  background: linear-gradient(90deg,
    rgba(0,0,0,0.04) 0%, rgba(0,0,0,0.08) 50%, rgba(0,0,0,0.04) 100%);
  background-size: 200% 100%;
}
@keyframes ui2Shimmer {
  0%   { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ══ MOBILE TOUCH TARGETS ════════════════════════════════════════════ */
@media (max-width: 768px) {
  .btn, .sh-btn { min-height: 44px; }

  /* Lighter hover lift on touch devices */
  .card:hover, .pdf-card:hover, .ottlib-card:hover {
    transform: translateY(-2px) !important;
  }
}

/* ══ REDUCED MOTION ══════════════════════════════════════════════════ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ══ PERFORMANCE ═════════════════════════════════════════════════════ */
.sh-orb, .ottlib-orb, .prm-orb { transform: translateZ(0); }
.page { overflow-x: hidden; }

/* ══ END STUDYRIA UI/UX 2.0 ══════════════════════════════════════════ */