/* ==========================================================
   LPK Latsol — base.css
   Design Tokens · Reset · Utilities · Components Universal
   Load order: base.css → student.css / quiz.css / admin.css
   ========================================================== */

/* --- CSS Custom Properties (Tokens) --- */
:root {
  /* Color Palette */
  --color-navy:        #1a1f36;
  --color-navy-700:    #252b45;
  --color-navy-600:    #2f3658;
  --color-navy-100:    #eef0f7;
  --color-red:         #d62839;
  --color-red-light:   #fbeaec;
  --color-red-hover:   #b81f2e;
  --color-orange:      #e8852a;
  --color-orange-light:#fff3e6;
  --color-green:       #1e8a5e;
  --color-green-light: #e6f5f0;
  --color-gray-900:    #111827;
  --color-gray-700:    #374151;
  --color-gray-500:    #6b7280;
  --color-gray-300:    #d1d5db;
  --color-gray-200:    #e5e7eb;
  --color-gray-100:    #f3f4f6;
  --color-gray-50:     #f9fafb;
  --color-white:       #ffffff;
  --color-bg:          #f5f5f0;

  /* Typography */
  --font-ui:     'Inter', 'Noto Sans JP', sans-serif;
  --font-jp:     'Noto Sans JP', 'Inter', sans-serif;

  /* Font Sizes */
  --text-xs:    0.75rem;
  --text-sm:    0.875rem;
  --text-base:  1rem;
  --text-md:    1.0625rem;
  --text-lg:    1.125rem;
  --text-xl:    1.25rem;
  --text-2xl:   1.5rem;
  --text-3xl:   1.875rem;
  --text-4xl:   2.25rem;

  /* Spacing */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Border */
  --radius-sm:  4px;
  --radius-md:  8px;
  --radius-lg:  12px;
  --radius-xl:  16px;
  --radius-full: 9999px;
  --border-color: var(--color-gray-200);

  /* Shadows */
  --shadow-sm:  0 1px 2px rgba(0,0,0,0.05);
  --shadow-md:  0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg:  0 4px 16px rgba(0,0,0,0.10);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* Layout */
  --sidebar-w:  220px;
  --header-h:   58px;
}

/* --- Reset & Base --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-ui);
  background-color: var(--color-bg);
  color: var(--color-gray-900);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

input, select, textarea {
  font-family: inherit;
  font-size: inherit;
}

/* --- Typography Utilities --- */
.text-xs    { font-size: var(--text-xs); }
.text-sm    { font-size: var(--text-sm); }
.text-base  { font-size: var(--text-base); }
.text-lg    { font-size: var(--text-lg); }
.text-xl    { font-size: var(--text-xl); }
.text-2xl   { font-size: var(--text-2xl); }
.text-3xl   { font-size: var(--text-3xl); }

.font-medium  { font-weight: 500; }
.font-semibold{ font-weight: 600; }
.font-bold    { font-weight: 700; }

.text-navy    { color: var(--color-navy); }
.text-red     { color: var(--color-red); }
.text-muted   { color: var(--color-gray-500); }
.text-white   { color: var(--color-white); }

.font-jp { font-family: var(--font-jp); }

/* --- Flexbox Utilities --- */
.flex         { display: flex; }
.flex-col     { flex-direction: column; }
.items-center { align-items: center; }
.items-start  { align-items: flex-start; }
.justify-center  { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end     { justify-content: flex-end; }
.gap-1  { gap: var(--space-1); }
.gap-2  { gap: var(--space-2); }
.gap-3  { gap: var(--space-3); }
.gap-4  { gap: var(--space-4); }
.gap-6  { gap: var(--space-6); }
.flex-1 { flex: 1; }

/* --- Spacing Utilities --- */
.p-2  { padding: var(--space-2); }
.p-3  { padding: var(--space-3); }
.p-4  { padding: var(--space-4); }
.p-6  { padding: var(--space-6); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }
.py-2 { padding-top: var(--space-2); padding-bottom: var(--space-2); }
.py-3 { padding-top: var(--space-3); padding-bottom: var(--space-3); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.625rem var(--space-5);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  line-height: 1;
  transition: background-color var(--transition-fast),
              border-color var(--transition-fast),
              color var(--transition-fast),
              box-shadow var(--transition-fast);
  white-space: nowrap;
  border: 1.5px solid transparent;
  letter-spacing: 0.01em;
}

.btn:focus-visible {
  outline: 2px solid var(--color-navy);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.45;
  pointer-events: none;
}

/* Primary */
.btn-primary {
  background-color: var(--color-navy);
  color: var(--color-white);
  border-color: var(--color-navy);
}
.btn-primary:hover {
  background-color: var(--color-navy-700);
  border-color: var(--color-navy-700);
}

/* Danger */
.btn-danger {
  background-color: var(--color-red);
  color: var(--color-white);
  border-color: var(--color-red);
}
.btn-danger:hover {
  background-color: var(--color-red-hover);
  border-color: var(--color-red-hover);
}

/* Outline */
.btn-outline {
  background-color: transparent;
  color: var(--color-navy);
  border-color: var(--color-gray-300);
}
.btn-outline:hover {
  background-color: var(--color-gray-100);
  border-color: var(--color-gray-400, #9ca3af);
}

/* Ghost */
.btn-ghost {
  background-color: transparent;
  color: var(--color-gray-700);
  border-color: transparent;
}
.btn-ghost:hover {
  background-color: var(--color-gray-100);
}

/* Icon button */
.btn-icon {
  padding: var(--space-2);
  border-radius: var(--radius-md);
  aspect-ratio: 1/1;
}

.btn-sm {
  padding: 0.4rem var(--space-3);
  font-size: var(--text-xs);
}

.btn-lg {
  padding: 0.8rem var(--space-8);
  font-size: var(--text-base);
}

/* --- Card --- */
.card {
  background-color: var(--color-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.card-sm {
  padding: var(--space-4);
}

/* --- Badge --- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 500;
  line-height: 1;
}

.badge-navy {
  background-color: var(--color-navy-100);
  color: var(--color-navy);
}

.badge-red {
  background-color: var(--color-red-light);
  color: var(--color-red);
}

.badge-green {
  background-color: var(--color-green-light);
  color: var(--color-green);
}

.badge-orange {
  background-color: var(--color-orange-light);
  color: var(--color-orange);
}

.badge-gray {
  background-color: var(--color-gray-100);
  color: var(--color-gray-500);
}

/* --- Progress Bar --- */
.progress-bar {
  width: 100%;
  height: 5px;
  background-color: var(--color-gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background-color: var(--color-navy);
  border-radius: var(--radius-full);
  transition: width var(--transition-slow);
}

/* --- Divider --- */
.divider {
  height: 1px;
  background-color: var(--border-color);
  margin: var(--space-4) 0;
}

/* --- Furigana / Ruby Text --- */
ruby {
  ruby-align: center;
}
rt {
  font-size: 0.55em;
  font-weight: 400;
  color: var(--color-gray-500);
  letter-spacing: 0;
}

/* --- Alert / Toast --- */
.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  border: 1px solid;
}

.alert-info {
  background-color: var(--color-navy-100);
  border-color: #c4c9e4;
  color: var(--color-navy);
}

.alert-danger {
  background-color: var(--color-red-light);
  border-color: #f5c0c5;
  color: var(--color-red);
}

.alert-success {
  background-color: var(--color-green-light);
  border-color: #a8d8c5;
  color: var(--color-green);
}

/* --- Modal Overlay --- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(26, 31, 54, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--space-4);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal {
  background-color: var(--color-white);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  max-width: 440px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  transform: translateY(8px);
  transition: transform var(--transition-base);
}

.modal-overlay.active .modal {
  transform: translateY(0);
}

.modal-title {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: var(--space-2);
}

.modal-body {
  color: var(--color-gray-700);
  font-size: var(--text-sm);
  line-height: 1.7;
  margin-bottom: var(--space-6);
}

.modal-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: flex-end;
}

/* --- Form Elements --- */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-gray-700);
}

.form-input {
  width: 100%;
  padding: 0.625rem var(--space-4);
  border: 1.5px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-gray-900);
  background-color: var(--color-white);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
}

.form-input:focus {
  border-color: var(--color-navy);
  box-shadow: 0 0 0 3px rgba(26, 31, 54, 0.08);
}

.form-input::placeholder {
  color: var(--color-gray-300);
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2.5rem;
}

/* --- Table --- */
.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.table th {
  text-align: left;
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-gray-50);
  color: var(--color-gray-500);
  font-weight: 500;
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border-color);
}

.table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-gray-100);
  color: var(--color-gray-700);
  vertical-align: middle;
}

.table tbody tr:hover {
  background-color: var(--color-gray-50);
}

/* --- Avatar --- */
.avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background-color: var(--color-navy-100);
  color: var(--color-navy);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: var(--text-sm);
  flex-shrink: 0;
}

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-gray-300); border-radius: var(--radius-full); }
::-webkit-scrollbar-thumb:hover { background: var(--color-gray-500); }

/* --- Utility --- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0);
  white-space: nowrap; border: 0;
}

.hidden { display: none !important; }
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.w-full { width: 100%; }
.min-w-0 { min-width: 0; }

/* --- Skeleton Loading --- */
.skeleton {
  background: linear-gradient(90deg, var(--color-gray-200) 25%, var(--color-gray-100) 50%, var(--color-gray-200) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
  border-radius: var(--radius-md);
}

@keyframes skeleton-shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* --- Animations --- */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.fade-in {
  animation: fadeIn var(--transition-base) both;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.6; }
}

/* --- Responsive --- */
@media (max-width: 768px) {
  :root {
    --sidebar-w: 0px;
  }
}