:root {
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 999px;

  --color-bg: #f4f5f7;
  --color-surface: #ffffff;
  --color-surface-raised: #fafbfc;
  --color-border: #dde1e6;
  --color-border-strong: #c2c8d1;
  --color-text: #1f2328;
  --color-text-muted: #656d78;
  --color-text-subtle: #97a0ab;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-active: #1e40af;
  --color-primary-subtle: #eaf0ff;
  --color-danger: #dc2626;
  --color-danger-subtle: #fdedec;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #14161a;
    --color-surface: #1c1f26;
    --color-surface-raised: #242832;
    --color-border: #333844;
    --color-border-strong: #454b58;
    --color-text: #e8eaed;
    --color-text-muted: #9aa1ab;
    --color-text-subtle: #6d7480;
    --color-primary: #6d97fb;
    --color-primary-hover: #8bacfc;
    --color-primary-active: #517fe8;
    --color-primary-subtle: #1c2a4d;
    --color-danger: #f87171;
    --color-danger-subtle: #3a1e1e;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
}

a { color: var(--color-primary); }

button, input, select {
  font-family: inherit;
  font-size: 14px;
}

.primary {
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  padding: 8px 16px;
  cursor: pointer;
}
.primary:hover { background: var(--color-primary-hover); }

.link-button {
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  text-decoration: underline;
}

.button-link {
  display: inline-block;
  text-decoration: none;
  margin-top: 12px;
}

/* --- 認証画面 --- */
.auth-shell {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.auth-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  width: 320px;
}
.auth-title {
  font-size: 18px;
  text-align: center;
  margin: 0 0 20px;
}
.auth-subtitle {
  font-size: 13px;
  color: var(--color-text-muted);
  text-align: center;
  margin: -12px 0 16px;
}
.auth-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 12px;
}
.auth-field input {
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-raised);
  color: var(--color-text);
}
.form-actions { margin-top: 16px; }
.form-actions .primary { width: 100%; }
.alert {
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  font-size: 13px;
}
.alert-danger {
  background: var(--color-danger-subtle);
  color: var(--color-danger);
}

/* --- ボード一覧 --- */
.page {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 16px 64px;
}
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 20px;
  margin-bottom: 16px;
}
.card h2 {
  font-size: 15px;
  margin: 0 0 12px;
  color: var(--color-text-muted);
}
.inline-form {
  display: flex;
  gap: 8px;
}
.inline-form input {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-raised);
  color: var(--color-text);
}
.inline-form input.password-optional {
  flex: 0 0 160px;
}
.field-hint {
  margin: 8px 0 0;
  font-size: 12px;
  color: var(--color-text-subtle);
}
.lock-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.03em;
  padding: 1px 5px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-subtle);
  color: var(--color-primary);
  margin-right: 6px;
}
.board-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.board-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border);
}
.board-list li:last-child { border-bottom: none; }
.board-list a {
  text-decoration: none;
  font-weight: 600;
}
.board-meta {
  color: var(--color-text-subtle);
  font-size: 12px;
}
.empty-state {
  color: var(--color-text-subtle);
  font-size: 13px;
}

/* --- ボード(キャンバス)画面 --- */
html, body.board-body {
  height: 100%;
  overflow: hidden;
}
.board-page {
  display: flex;
  flex-direction: column;
  height: 100vh;
}
.board-topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 16px;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  flex-shrink: 0;
}
.board-back {
  text-decoration: none;
  font-size: 18px;
}
.board-name {
  font-size: 15px;
  margin: 0;
  flex: 1;
}
.conn-status {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-danger);
  background: var(--color-danger-subtle);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  white-space: nowrap;
}
.presence-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  max-width: 45%;
}
.presence-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  height: 26px;
  padding: 0 8px 0 4px;
  border-radius: var(--radius-full);
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  font-size: 12px;
  color: var(--color-text);
  white-space: nowrap;
}
.presence-chip .presence-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.help-wrapper {
  position: relative;
}
.help-btn {
  width: 30px;
  height: 30px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface-raised);
  color: var(--color-text-muted);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}
.help-btn:hover {
  border-color: var(--color-border-strong);
  color: var(--color-text);
}
.help-panel {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 320px;
  max-height: 70vh;
  overflow-y: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  padding: 16px;
  z-index: 500;
}
.help-panel h2 {
  font-size: 14px;
  margin: 0 0 12px;
}
.help-panel dl {
  margin: 0;
  font-size: 12px;
}
.help-panel dt {
  font-weight: 700;
  color: var(--color-primary);
  margin-top: 10px;
}
.help-panel dt:first-child {
  margin-top: 0;
}
.help-panel dd {
  margin: 4px 0 0;
  color: var(--color-text-muted);
  line-height: 1.5;
}
.help-panel .auth-field {
  margin: 12px 0 0;
}
.help-panel .auth-field input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-raised);
  color: var(--color-text);
}
.help-panel .form-actions {
  margin-top: 10px;
}

.board-toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface-raised);
  flex-shrink: 0;
}
.tool-btn {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  min-width: 36px;
  height: 32px;
  padding: 0 10px;
  cursor: pointer;
  color: var(--color-text);
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.tool-btn:hover { border-color: var(--color-border-strong); }
.tool-btn.active {
  background: var(--color-primary-subtle);
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.tool-upload { position: relative; }
.toolbar-sep {
  width: 1px;
  height: 20px;
  background: var(--color-border);
  margin: 0 4px;
}
.zoom-label {
  font-size: 12px;
  color: var(--color-text-muted);
  width: 42px;
  text-align: center;
}
#color-picker {
  width: 32px;
  height: 32px;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: none;
  cursor: pointer;
}
#font-size-input {
  width: 52px;
  height: 32px;
  padding: 0 6px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text);
}

.canvas-container {
  flex: 1;
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(circle, var(--color-border) 1px, transparent 1px) 0 0 / 24px 24px,
    var(--color-bg);
}

.cursor-label {
  pointer-events: none;
}

/* --- 参加者名モーダル --- */
.identity-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
}
.identity-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 24px;
  width: 280px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.identity-card p {
  margin: 0;
  font-size: 13px;
  color: var(--color-text-muted);
}
.identity-card input {
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface-raised);
  color: var(--color-text);
}