/* ===================================
   style.css — 簿記3級合格サポート
   Udemy-like Design System
   =================================== */

/* ---------- CSS Variables ---------- */
:root {
  /* Udemy color palette */
  --color-primary:      #a435f0;
  --color-primary-dark: #8710d8;
  --color-header-bg:    #1c1d1f;
  --color-text-dark:    #1c1d1f;
  --color-text-muted:   #6a6f73;
  --color-text-light:   #ffffff;
  --color-bg:           #f7f9fa;
  --color-surface:      #ffffff;
  --color-border:       #d1d7dc;
  --color-success:      #1ea31e;
  --color-warning:      #f69c08;
  --color-error:        #d03a24;

  /* 5大要素カラー */
  --color-asset:        #5624d0;
  --color-asset-bg:     #f0ebff;
  --color-liability:    #d03a24;
  --color-liability-bg: #fff0ee;
  --color-equity:       #1e7e34;
  --color-equity-bg:    #edfff2;
  --color-revenue:      #f07819;
  --color-revenue-bg:   #fff8ee;
  --color-expense:      #8710d8;
  --color-expense-bg:   #f8f0ff;

  /* Spacing */
  --space-xs:  4px;
  --space-sm:  8px;
  --space-md:  16px;
  --space-lg:  24px;
  --space-xl:  32px;
  --space-2xl: 48px;

  /* Layout */
  --sidebar-width: 240px;
  --header-height: 56px;
  --content-max-width: 1100px;

  /* Typography */
  --font-family: "Udemy Sans", "SF Pro Text", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-size-xs:  11px;
  --font-size-sm:  13px;
  --font-size-md:  15px;
  --font-size-lg:  17px;
  --font-size-xl:  20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 30px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.12);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.16);

  /* Transitions */
  --transition: 0.15s ease;
}

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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  color: var(--color-text-dark);
  background: var(--color-bg);
  line-height: 1.6;
  min-height: 100vh;
}

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

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

ul, ol { padding-left: var(--space-lg); }

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

/* ---------- Layout ---------- */
.layout {
  display: flex;
  min-height: calc(100vh - var(--header-height));
  padding-top: var(--header-height);
}

.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: var(--space-xl) var(--space-xl);
  max-width: calc(var(--content-max-width) + var(--sidebar-width));
}

@media (max-width: 900px) {
  .main-content { margin-left: 0; padding: var(--space-md); }
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
}

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-height);
  background: var(--color-header-bg);
  display: flex;
  align-items: center;
  padding: 0 var(--space-xl);
  z-index: 1000;
  border-bottom: 1px solid #3e4143;
}

.site-header .logo {
  color: var(--color-text-light);
  font-size: var(--font-size-lg);
  font-weight: 700;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.site-header .logo .logo-icon {
  background: var(--color-primary);
  color: white;
  width: 30px; height: 30px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 800;
}

.header-right {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.header-streak {
  color: var(--color-warning);
  font-size: var(--font-size-sm);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 4px;
}

.header-overall-progress {
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header-progress-bar {
  width: 120px;
  height: 6px;
  background: #3e4143;
  border-radius: 3px;
  overflow: hidden;
}

.header-progress-bar .fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: 3px;
  transition: width 0.5s ease;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 20px;
  cursor: pointer;
  margin-right: var(--space-sm);
}

@media (max-width: 900px) { .hamburger { display: block; } }

/* ---------- Sidebar ---------- */
.sidebar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: var(--sidebar-width);
  height: calc(100vh - var(--header-height));
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  z-index: 900;
  transition: transform var(--transition);
}

.sidebar-section-title {
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  padding: var(--space-lg) var(--space-md) var(--space-xs);
}

.sidebar-nav { list-style: none; padding: 0; }

.sidebar-nav li a {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 10px var(--space-md);
  color: var(--color-text-dark);
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: background var(--transition), border-color var(--transition);
}

.sidebar-nav li a:hover {
  background: var(--color-bg);
  text-decoration: none;
}

.sidebar-nav li a.active {
  border-left-color: var(--color-primary);
  background: #f8f0ff;
  color: var(--color-primary);
  font-weight: 700;
}

.sidebar-nav li a .nav-icon { font-size: 16px; width: 20px; text-align: center; }
.sidebar-nav li a .nav-badge {
  margin-left: auto;
  background: var(--color-primary);
  color: white;
  font-size: 10px;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: 10px;
}

.sidebar-progress-mini {
  padding: var(--space-md);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.sidebar-progress-mini .label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-bottom: 4px;
}

/* ---------- Page Header ---------- */
.page-header {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.page-header .breadcrumb {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.page-header .breadcrumb a { color: var(--color-primary); }

.page-header h1 {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text-dark);
  line-height: 1.2;
}

.page-header .subtitle {
  color: var(--color-text-muted);
  font-size: var(--font-size-md);
  margin-top: var(--space-sm);
}

/* ---------- Typography ---------- */
h1 { font-size: var(--font-size-3xl); font-weight: 700; }
h2 { font-size: var(--font-size-2xl); font-weight: 700; margin-bottom: var(--space-md); }
h3 { font-size: var(--font-size-xl); font-weight: 600; margin-bottom: var(--space-sm); }
h4 { font-size: var(--font-size-lg); font-weight: 600; }

.section-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text-dark);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 10px 20px;
  font-size: var(--font-size-md);
  font-weight: 700;
  font-family: var(--font-family);
  border: none;
  border-radius: 0;
  cursor: pointer;
  transition: background var(--transition), transform 0.1s;
  text-decoration: none;
  white-space: nowrap;
}

.btn:active { transform: scale(0.98); }

.btn-primary {
  background: var(--color-primary);
  color: white;
}
.btn-primary:hover { background: var(--color-primary-dark); text-decoration: none; color: white; }

.btn-secondary {
  background: transparent;
  color: var(--color-text-dark);
  border: 2px solid var(--color-text-dark);
}
.btn-secondary:hover { background: var(--color-text-dark); color: white; }

.btn-success {
  background: var(--color-success);
  color: white;
}
.btn-success:hover { background: #177c17; }

.btn-outline-primary {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}
.btn-outline-primary:hover { background: var(--color-primary); color: white; }

.btn-sm { padding: 6px 14px; font-size: var(--font-size-sm); }
.btn-lg { padding: 14px 28px; font-size: var(--font-size-lg); }
.btn-block { width: 100%; }

/* ---------- Cards ---------- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  overflow: hidden;
  transition: box-shadow var(--transition);
}

.card:hover { box-shadow: var(--shadow-md); }

.card-header {
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--color-border);
  font-weight: 700;
  font-size: var(--font-size-lg);
}

.card-body { padding: var(--space-lg); }
.card-footer {
  padding: var(--space-md) var(--space-lg);
  border-top: 1px solid var(--color-border);
  background: var(--color-bg);
}

/* Course card (like Udemy) */
.course-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  overflow: hidden;
  transition: box-shadow var(--transition);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: block;
}

.course-card:hover { box-shadow: var(--shadow-lg); text-decoration: none; color: inherit; }

.course-card-thumb {
  width: 100%;
  height: 140px;
  background: var(--color-header-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 48px;
  position: relative;
  overflow: hidden;
}

.course-card-thumb::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(164,53,240,0.3), transparent);
}

.course-card-body { padding: var(--space-md); }

.course-card-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--space-xs);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.course-card-meta {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

/* ---------- Progress Bars ---------- */
.progress {
  height: 8px;
  background: #e8e8e8;
  border-radius: 4px;
  overflow: hidden;
}

.progress .progress-fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: 4px;
  transition: width 0.5s ease;
}

.progress.success .progress-fill { background: var(--color-success); }
.progress.warning .progress-fill { background: var(--color-warning); }
.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: 4px;
}

/* ---------- Badges ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-size: var(--font-size-xs);
  font-weight: 700;
  border-radius: 2px;
}

.badge-primary   { background: var(--color-primary);   color: white; }
.badge-success   { background: var(--color-success);   color: white; }
.badge-warning   { background: #eceb98; color: #3e3b00; }
.badge-danger    { background: var(--color-error);     color: white; }
.badge-muted     { background: #e8e8e8; color: var(--color-text-muted); }

/* 5大要素バッジ */
.badge-asset     { background: var(--color-asset-bg);     color: var(--color-asset);     border: 1px solid var(--color-asset); }
.badge-liability { background: var(--color-liability-bg); color: var(--color-liability); border: 1px solid var(--color-liability); }
.badge-equity    { background: var(--color-equity-bg);    color: var(--color-equity);    border: 1px solid var(--color-equity); }
.badge-revenue   { background: var(--color-revenue-bg);   color: var(--color-revenue);   border: 1px solid var(--color-revenue); }
.badge-expense   { background: var(--color-expense-bg);   color: var(--color-expense);   border: 1px solid var(--color-expense); }

/* ---------- Alerts / Messages ---------- */
.alert {
  padding: var(--space-md) var(--space-lg);
  border-radius: 4px;
  font-size: var(--font-size-md);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
}

.alert-success { background: #edfff2; border-left: 4px solid var(--color-success); color: #155215; }
.alert-warning { background: #fffbe6; border-left: 4px solid var(--color-warning); color: #6b4e00; }
.alert-error   { background: #fff0ee; border-left: 4px solid var(--color-error);   color: #9b1a09; }
.alert-info    { background: #f0ebff; border-left: 4px solid var(--color-primary); color: #3b0e8e; }

/* ---------- Tables ---------- */
.table-wrapper { overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

thead {
  background: var(--color-header-bg);
  color: white;
}

th, td {
  padding: 10px var(--space-md);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

tr:hover td { background: var(--color-bg); }

/* ---------- Stat Boxes ---------- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.stat-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: var(--space-lg);
  text-align: center;
}

.stat-box .stat-value {
  font-size: 32px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 4px;
}

.stat-box .stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ---------- Course Grid ---------- */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: var(--space-lg);
}

/* ---------- Dashboard Analytics ---------- */
.insight-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-md);
}

.insight-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 170px;
}

.insight-label {
  font-size: var(--font-size-xs);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.insight-value {
  font-size: 36px;
  font-weight: 800;
  line-height: 1;
  color: var(--color-primary);
}

.insight-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
}

.insight-meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: auto;
}

.trend-up { color: var(--color-success); }
.trend-down { color: var(--color-error); }
.trend-flat { color: var(--color-text-muted); }

.priority-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.priority-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-surface);
}

.priority-item.priority-info {
  background: #faf7ff;
  border-color: #d8c7ff;
}

.priority-item.priority-warning {
  background: #fffaf0;
  border-color: #f5d48a;
}

.priority-item.priority-success {
  background: #f3fff4;
  border-color: #b7e3bd;
}

.priority-rank {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-header-bg);
  color: white;
  font-size: var(--font-size-sm);
  font-weight: 800;
  flex-shrink: 0;
}

.priority-main {
  flex: 1;
  min-width: 0;
}

.priority-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  margin-bottom: 2px;
}

.priority-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.module-analysis-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.module-analysis-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  background: var(--color-surface);
}

.module-analysis-row.is-priority {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.module-analysis-row.exam-focus {
  background: #fcfbff;
}

.module-analysis-main {
  flex: 1;
  min-width: 0;
}

.module-analysis-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-md);
}

.module-analysis-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  margin-bottom: 2px;
}

.module-analysis-meta,
.module-analysis-submeta {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.module-analysis-submeta {
  display: flex;
  justify-content: space-between;
  gap: var(--space-md);
  margin-top: 6px;
  flex-wrap: wrap;
}

@media (max-width: 720px) {
  .priority-item,
  .module-analysis-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .module-analysis-head {
    width: 100%;
    flex-direction: column;
  }

  .module-analysis-row .btn,
  .priority-item .btn {
    width: 100%;
  }
}

/* ---------- Accordion ---------- */
.accordion { border: 1px solid var(--color-border); border-radius: 4px; overflow: hidden; }
.accordion-item { border-bottom: 1px solid var(--color-border); }
.accordion-item:last-child { border-bottom: none; }

.accordion-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  background: var(--color-surface);
  cursor: pointer;
  font-weight: 600;
  font-size: var(--font-size-md);
  user-select: none;
  transition: background var(--transition);
}

.accordion-header:hover { background: var(--color-bg); }
.accordion-header .chevron {
  font-size: 12px;
  transition: transform var(--transition);
  color: var(--color-text-muted);
}

.accordion-item.open .accordion-header .chevron { transform: rotate(180deg); }
.accordion-body {
  display: none;
  padding: var(--space-lg);
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
}
.accordion-item.open .accordion-body { display: block; }

/* ---------- Tabs ---------- */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: var(--space-lg);
}

.tab-btn {
  padding: 10px var(--space-lg);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-text-muted);
  cursor: pointer;
  font-family: var(--font-family);
  transition: color var(--transition), border-color var(--transition);
}

.tab-btn:hover { color: var(--color-text-dark); }
.tab-btn.active { color: var(--color-primary); border-bottom-color: var(--color-primary); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ---------- Quiz / Question Styles ---------- */
.question-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: var(--space-xl);
  margin-bottom: var(--space-lg);
}

.question-number {
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.question-text {
  font-size: var(--font-size-lg);
  font-weight: 600;
  line-height: 1.6;
  margin-bottom: var(--space-lg);
  color: var(--color-text-dark);
}

.options-list { list-style: none; padding: 0; display: flex; flex-direction: column; gap: var(--space-sm); }

.option-btn {
  width: 100%;
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: 4px;
  font-size: var(--font-size-md);
  font-family: var(--font-family);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.option-btn:hover { border-color: var(--color-primary); background: var(--color-asset-bg); }
.option-btn.selected { border-color: var(--color-primary); background: var(--color-asset-bg); }
.option-btn.correct { border-color: var(--color-success); background: var(--color-equity-bg); }
.option-btn.wrong { border-color: var(--color-error); background: var(--color-liability-bg); }
.option-btn .option-letter {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--font-size-sm);
  flex-shrink: 0;
}

/* ---------- Flashcard ---------- */
.flashcard-container {
  perspective: 1000px;
  margin: 0 auto;
  max-width: 560px;
}

.flashcard {
  width: 100%;
  height: 280px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s;
  cursor: pointer;
}

.flashcard.flipped { transform: rotateY(180deg); }

.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  text-align: center;
  background: var(--color-surface);
}

.flashcard-back {
  transform: rotateY(180deg);
  background: var(--color-header-bg);
  color: white;
}

.flashcard-label {
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.flashcard-term {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.flashcard-hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* ---------- Drag & Drop ---------- */
.dnd-categories {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.dnd-category-box {
  min-height: 140px;
  border: 2px dashed var(--color-border);
  border-radius: 4px;
  padding: var(--space-md);
  transition: border-color var(--transition), background var(--transition);
}

.dnd-category-box.dragover {
  border-color: var(--color-primary);
  background: var(--color-asset-bg);
}

.dnd-category-box.correct { border-color: var(--color-success); background: var(--color-equity-bg); }
.dnd-category-box.wrong   { border-color: var(--color-error);   background: var(--color-liability-bg); }

.dnd-category-title {
  font-size: var(--font-size-sm);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: 6px;
}

.dnd-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 8px 12px;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: grab;
  display: inline-block;
  margin: 4px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
  user-select: none;
}

.dnd-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.dnd-card:active { cursor: grabbing; }
.dnd-card.dragging { opacity: 0.5; }

/* ---------- Timer ---------- */
.timer-display {
  font-size: 48px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  text-align: center;
  padding: var(--space-xl);
  color: var(--color-text-dark);
}

.timer-display.warning { color: var(--color-warning); }
.timer-display.danger  { color: var(--color-error); animation: pulse 1s infinite; }

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

/* ---------- Score / Result ---------- */
.result-banner {
  text-align: center;
  padding: var(--space-2xl);
  background: linear-gradient(135deg, #1c1d1f 0%, #3b0e8e 100%);
  color: white;
  border-radius: 4px;
  margin-bottom: var(--space-xl);
}

.result-score {
  font-size: 72px;
  font-weight: 700;
  line-height: 1;
  margin-bottom: var(--space-sm);
}

.result-score.pass { color: #5be85b; }
.result-score.fail { color: #ff6b6b; }

.result-label {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-md);
}

/* ---------- Journal Entry Table ---------- */
.journal-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-md);
}

.journal-table th {
  background: var(--color-header-bg);
  color: white;
  padding: 8px var(--space-md);
  font-weight: 600;
  text-align: center;
}

.journal-table td {
  padding: 8px var(--space-md);
  border: 1px solid var(--color-border);
}

.journal-table .debit-col { border-right: 3px solid var(--color-border); }
.journal-table .amount { text-align: right; font-variant-numeric: tabular-nums; }

/* ---------- Category Side Border ---------- */
.category-border-asset    { border-left: 4px solid var(--color-asset); }
.category-border-liability{ border-left: 4px solid var(--color-liability); }
.category-border-equity   { border-left: 4px solid var(--color-equity); }
.category-border-revenue  { border-left: 4px solid var(--color-revenue); }
.category-border-expense  { border-left: 4px solid var(--color-expense); }

/* ---------- Toast Notifications ---------- */
#toast-container {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.toast {
  padding: var(--space-md) var(--space-lg);
  border-radius: 4px;
  color: white;
  font-weight: 600;
  font-size: var(--font-size-md);
  box-shadow: var(--shadow-lg);
  animation: slideIn 0.3s ease;
  max-width: 320px;
}

.toast.success { background: var(--color-success); }
.toast.error   { background: var(--color-error); }
.toast.info    { background: var(--color-primary); }

@keyframes slideIn { from { transform: translateX(100px); opacity: 0; } to { transform: none; opacity: 1; } }

/* ---------- Modal ---------- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-md);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
}

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

.modal {
  background: var(--color-surface);
  border-radius: 4px;
  max-width: 640px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  transform: scale(0.9);
  transition: transform var(--transition);
}

.modal-overlay.open .modal { transform: scale(1); }

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
  font-weight: 700;
  font-size: var(--font-size-lg);
}

.modal-close {
  background: none;
  border: none;
  font-size: 20px;
  cursor: pointer;
  color: var(--color-text-muted);
  width: 32px; height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-body { padding: var(--space-lg); }
.modal-footer { padding: var(--space-lg); border-top: 1px solid var(--color-border); display: flex; gap: var(--space-sm); justify-content: flex-end; }

/* ---------- Explanation Box ---------- */
.explanation-box {
  background: #f0ebff;
  border: 1px solid #c4a8ff;
  border-radius: 4px;
  padding: var(--space-lg);
  margin-top: var(--space-md);
}

.explanation-box .explanation-title {
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.key-point-box {
  background: #eceb98;
  border-radius: 4px;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: #3e3b00;
  margin-top: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ---------- Empty State ---------- */
.empty-state {
  text-align: center;
  padding: var(--space-2xl);
  color: var(--color-text-muted);
}

.empty-state .empty-icon { font-size: 64px; margin-bottom: var(--space-md); }
.empty-state h3 { color: var(--color-text-dark); margin-bottom: var(--space-sm); }

/* ---------- Confetti overlay ---------- */
#confetti-canvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9998;
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #c4c4c4; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #a0a0a0; }

/* ---------- Utilities ---------- */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-lg); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-lg); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.text-center { text-align: center; }
.text-right  { text-align: right; }
.text-muted  { color: var(--color-text-muted); }
.text-sm     { font-size: var(--font-size-sm); }
.text-lg     { font-size: var(--font-size-lg); }
.font-bold   { font-weight: 700; }
.w-full      { width: 100%; }
.hidden      { display: none !important; }

@media (max-width: 768px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .page-header h1 { font-size: var(--font-size-2xl); }
}

@media (max-width: 480px) {
  /* CSS変数をモバイル向けに拡大 */
  :root {
    --font-size-xs:  13px;
    --font-size-sm:  14px;
    --font-size-md:  16px;
    --font-size-lg:  18px;
    --font-size-xl:  21px;
  }

  .stats-grid { grid-template-columns: 1fr; }
  .course-grid { grid-template-columns: 1fr; }
  .insight-grid { grid-template-columns: 1fr; }
  .dnd-categories { grid-template-columns: 1fr; }
  .header-progress-bar { width: 80px; }
  .site-header { padding: 0 var(--space-sm); }
  .tab-btn { padding: 10px var(--space-md); font-size: var(--font-size-sm); }
  .tabs { overflow-x: auto; -webkit-overflow-scrolling: touch; white-space: nowrap; }
  .page-header h1 { font-size: var(--font-size-xl); }
  .btn { min-height: 44px; }
  .btn-sm { min-height: 44px; padding: 10px 14px; }
  #toast-container { right: var(--space-sm); left: var(--space-sm); }
  .toast { max-width: 100%; }
  .timer-display { font-size: 36px; }
  .result-score { font-size: 56px; }
  .flashcard { height: 220px; }
  .flashcard-term { font-size: var(--font-size-2xl); }
  select, input[type="text"], input[type="number"] { font-size: 16px !important; }

  /* モバイル余白・パディング調整 */
  .card-body { padding: var(--space-md); }
  .question-box { padding: var(--space-lg); }
  .stat-box { padding: var(--space-md); }
  .stat-box .stat-value { font-size: 28px; }
  .alert { padding: var(--space-md); }
  .modal-body { padding: var(--space-md); }
  .modal-header { padding: var(--space-md); }

  /* リテラル値インラインfont-size対策 */
  .main-content { font-size: 16px; }
  .main-content .account-def,
  .main-content .account-example,
  .main-content .memory-tip,
  .main-content .account-en { font-size: 14px; }
}