/* =========================================================
   TIN HỌC HUB - STYLESHEET TƯƠNG THÍCH ĐA TỈ LỆ KHUNG HÌNH
   Hỗ trợ 100% Phone (16:9 đến 21:9), Foldables, Tablet, Desktop, Ultrawide
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,300;0,400;0,500;0,600;0,700;0,800;1,400&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  --font-main: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --sat: env(safe-area-inset-top, 0px);
  --sar: env(safe-area-inset-right, 0px);
  --sab: env(safe-area-inset-bottom, 0px);
  --sal: env(safe-area-inset-left, 0px);
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-main);
  min-height: 100dvh;
  min-height: -webkit-fill-available;
  overflow-x: hidden;
  padding-top: var(--sat);
  padding-left: var(--sal);
  padding-right: var(--sar);
  -webkit-tap-highlight-color: transparent;
  transition: background-color 0.2s ease, color 0.2s ease;
}

code, pre, .font-code {
  font-family: var(--font-mono);
}

/* Tối ưu cảm ứng cho điện thoại & máy tính bảng (loại bỏ 300ms delay) */
button, a, input, select, textarea, [role="button"] {
  touch-action: manipulation;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: rgba(0, 0, 0, 0.03);
}

.dark ::-webkit-scrollbar-track {
  background: rgba(255, 255, 255, 0.03);
}

::-webkit-scrollbar-thumb {
  background: rgba(100, 116, 139, 0.3);
  border-radius: 9999px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(100, 116, 139, 0.5);
}

/* Glassmorphism */
.glass-panel {
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.dark .glass-panel {
  background: rgba(15, 23, 42, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

/* Option Cards for Questions (Touch Target >= 44px) */
.option-btn {
  min-height: 48px;
  transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  user-select: none;
  -webkit-user-select: none;
}

.option-btn:hover:not(:disabled) {
  transform: translateY(-1px);
}

.option-btn.selected {
  border-color: #3b82f6 !important;
  background-color: rgba(59, 130, 246, 0.08) !important;
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.25);
}

.dark .option-btn.selected {
  border-color: #60a5fa !important;
  background-color: rgba(96, 165, 250, 0.15) !important;
  box-shadow: 0 0 0 2px rgba(96, 165, 250, 0.3);
}

.option-btn.correct {
  border-color: #10b981 !important;
  background-color: rgba(16, 185, 129, 0.12) !important;
  box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.3);
}

.option-btn.wrong {
  border-color: #ef4444 !important;
  background-color: rgba(239, 68, 68, 0.12) !important;
  box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.3);
}

/* Palette items for Exam mode */
.palette-btn {
  min-width: 36px;
  min-height: 36px;
  transition: all 0.15s ease;
}

.palette-btn.unanswered {
  background-color: #f1f5f9;
  color: #475569;
  border: 1px solid #cbd5e1;
}

.dark .palette-btn.unanswered {
  background-color: #1e293b;
  color: #94a3b8;
  border: 1px solid #334155;
}

.palette-btn.answered {
  background-color: #3b82f6;
  color: #ffffff;
  border: 1px solid #2563eb;
}

.palette-btn.flagged {
  border: 2px solid #f59e0b !important;
  position: relative;
}

.palette-btn.flagged::after {
  content: '';
  position: absolute;
  top: 1px;
  right: 1px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: #f59e0b;
}

.palette-btn.active {
  box-shadow: 0 0 0 2px #fff, 0 0 0 4px #3b82f6;
}

.dark .palette-btn.active {
  box-shadow: 0 0 0 2px #0f172a, 0 0 0 4px #60a5fa;
}

/* Animations */
@keyframes pulse-subtle {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.85; }
}

.animate-pulse-subtle {
  animation: pulse-subtle 2s infinite ease-in-out;
}

/* Mobile Bottom Navigation Bar (Dành cho màn hình điện thoại tỉ lệ 16:9 đến 21:9) */
.mobile-bottom-bar {
  padding-bottom: calc(var(--sab) + 0.35rem);
}

body.in-exam .mobile-bottom-bar {
  display: none !important;
}

/* Tránh che nội dung trên màn hình điện thoại có bottom bar */
@media (max-width: 768px) {
  body:not(.in-exam) {
    padding-bottom: calc(var(--sab) + 4.5rem);
  }
}

/* =========================================================
   PRINT STYLES - XUẤT ĐỀ THI & ĐÁP ÁN RA GIẤY / PDF
   ========================================================= */
@media print {
  body {
    background: #ffffff !important;
    color: #000000 !important;
    font-size: 11pt !important;
    line-height: 1.4 !important;
    padding: 0 !important;
  }

  .no-print, header, nav, footer, #timer-container, #palette-container, .btn-action, .modal-backdrop, .mobile-bottom-bar {
    display: none !important;
  }

  #print-area {
    display: block !important;
    width: 100% !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  .print-page-break {
    page-break-before: always;
  }

  .print-header {
    border-bottom: 2px solid #000;
    padding-bottom: 10px;
    margin-bottom: 20px;
  }

  .print-question {
    page-break-inside: avoid;
    margin-bottom: 14px;
    font-size: 11pt;
  }

  .print-option {
    margin-left: 15px;
    margin-top: 4px;
  }
}