:root {
  --bg: #f7faff;
  --panel: #ffffff;
  --menu-bg: #eef4ff;
  --line: #d9e3f5;
  --text: #334155;
  --subtext: #64748b;
  --primary: #8fb3ff;
  --primary-hover: #7aa2f8;
  --soft: #f8fbff;
  --success: #5bb98c;
  --danger: #d97b7b;
  --shadow: 0 6px 18px rgba(80, 110, 170, 0.08);
  --radius: 18px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "M PLUS Rounded 1c", "Hiragino Maru Gothic ProN", sans-serif;
  font-weight: 400;
  letter-spacing: 0.05em;
  height: 100%;
}

body {
  min-height: 100vh;
}

.app {
  display: grid;
  grid-template-columns: 240px 1fr;
  min-height: 100vh;
}

.sidebar {
  background: var(--menu-bg);
  border-right: 1px solid var(--line);
  padding: 20px 16px;
}

.brand {
  margin-bottom: 20px;
  padding: 14px 12px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.9);
  border-radius: 16px;
  box-shadow: var(--shadow);
}

.brand-title {
  font-size: 20px;
  font-weight: 700;
  margin: 0 0 6px;
}

.brand-sub {
  font-size: 13px;
  color: var(--subtext);
  margin: 0;
  line-height: 1.6;
}

.menu-title {
  font-size: 13px;
  color: var(--subtext);
  margin: 20px 6px 8px;
}

.menu-list {
  display: grid;
  gap: 10px;
}

.menu-button {
  width: 100%;
  border: 1px solid transparent;
  border-radius: 14px;
  background: #fff;
  color: var(--text);
  padding: 12px 14px;
  text-align: left;
  font-size: 15px;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: 0.2s ease;
}

.menu-button:hover {
  background: #fdfefe;
  transform: translateY(-1px);
}

.menu-button.active {
  border-color: #b9cdfb;
  background: #f8fbff;
  font-weight: 700;
}

.content {
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 18px;
  padding: 20px;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.settings-panel {
  padding: 18px 20px;
}

.panel-title {
  margin: 0 0 14px;
  font-size: 20px;
  font-weight: 700;
}

.panel-subtitle {
  margin: 0 0 18px;
  font-size: 13px;
  color: var(--subtext);
  line-height: 1.6;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(220px, 1fr));
  gap: 16px 20px;
  align-items: start;
}

.inline-checkbox-group {
  display: flex;
  gap: 12px;
  margin-top: 4px;
}

.field {
  display: grid;
  gap: 8px;
}

.field label,
.checkbox-label,
.power-label {
  font-size: 14px;
}

.field input[type="number"],
.field select {
  width: 100%;
  max-width: 180px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--soft);
  color: var(--text);
  padding: 10px 12px;
  font-size: 15px;
  outline: none;
}

.field input[type="number"]:focus,
.field select:focus {
  border-color: #a8c2ff;
  background: #fff;
}

.checkbox-group {
  display: grid;
  gap: 10px;
  padding-top: 2px;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}

.power-options {
  display: none;
  margin-top: 8px;
  padding: 12px;
  border: 1px dashed #c6d5f7;
  border-radius: 14px;
  background: #fbfdff;
  gap: 8px;
}

.power-options.visible {
  display: grid;
}

.power-label {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.action-button {
  border: none;
  border-radius: 14px;
  background: var(--primary);
  color: #fff;
  padding: 11px 18px;
  font-size: 15px;
  cursor: pointer;
  transition: 0.2s ease;
}

.action-button:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.action-button.secondary {
  background: #c3d7ff;
  color: #27406b;
}

.action-button.secondary:hover {
  background: #b2cbff;
}

.problems-panel {
  padding: 20px;
  overflow: auto;
}

.problem-header {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 18px;
}

.problem-title-wrap {
  display: grid;
  gap: 4px;
}

.problem-title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
}

.problem-note {
  font-size: 13px;
  color: var(--subtext);
}

.sheet {
  display: grid;
  grid-template-columns: repeat(2, minmax(260px, 1fr));
  gap: 16px 28px;
  align-content: start;
}

.question-item {
  padding: 12px 14px;
  border: 1px solid #e7eefb;
  border-radius: 14px;
  background: #fcfdff;
  font-size: 22px;
  line-height: 2;
  word-break: break-word;
}

.question-number {
  font-weight: 700;
  margin-right: 8px;
  color: #5d78a6;
}

.blank {
  display: inline-block;
  min-width: 88px;
  border-bottom: 2px solid #b6c7e8;
  transform: translateY(-2px);
}

.empty-state {
  padding: 28px 20px;
  border: 1px dashed #cad8f4;
  border-radius: 16px;
  background: #fbfdff;
  color: var(--subtext);
  line-height: 1.8;
  text-align: center;
}

.footer-credit {
  margin-top: 18px;
  font-size: 12px;
  color: var(--subtext);
  text-align: right;
}

.footer {
  margin-top: 40px;
  padding: 16px;
  background: #f8f8f8;
  border-top: 1px solid #ddd;
}

.footer-inner {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  font-size: 13px;
  color: #666;
}

.footer-inner a {
  margin: 0 8px;
  color: #666;
  text-decoration: none;
}

.footer-inner a:hover {
  text-decoration: underline;
}

.footer-domain {
  display: block;
  margin-top: 6px;
  font-size: 11px;
  color: #999;
}

.fraction {
  display: inline-block;
  text-align: center;
  vertical-align: middle;
  font-size: 1.1em;
}

.fraction .num {
  display: block;
  border-bottom: 2px solid #333;
  padding: 0 4px;
}

.fraction .den {
  display: block;
  padding: 0 4px;
}

.terms-container {
  max-width: 800px;
  margin: 40px auto;
  padding: 24px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

.terms-title {
  font-size: 24px;
  margin-bottom: 16px;
  text-align: center;
}

.terms-content {
  max-height: 70vh;
  overflow-y: auto;
  line-height: 1.8;
  font-size: 14px;
  padding-right: 8px;
}

.terms-content p {
  margin-bottom: 12px;
}

@media (max-width: 980px) {
  .app {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--line);
  }

  .content {
    grid-template-rows: auto auto;
  }

  .settings-grid {
    grid-template-columns: 1fr;
  }

  .sheet {
    grid-template-columns: 1fr;
  }
}

@media print {
  body {
    background: #fff;
  }

  .app {
    display: block;
  }

  .sidebar,
  .settings-panel,
  .footer-credit {
    display: none !important;
  }

  .content {
    display: block;
    padding: 0;
  }

  .problems-panel {
    border: none;
    box-shadow: none;
    padding: 0;
  }

  .problem-header {
    margin-bottom: 12px;
  }

  .problem-note {
    display: none;
  }

  .sheet {
    grid-template-columns: 1fr 1fr;
    gap: 10px 18px;
  }

  .question-item {
    border: none;
    background: transparent;
    padding: 4px 0;
    border-radius: 0;
    box-shadow: none;
    font-size: 18px;
  }
}