@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

:root {
  --bg: #10141c;
  --panel: #171d28;
  --panel-alt: #1d2432;
  --panel-raised: #232b3a;
  --border: #262e3d;
  --border-soft: #1e2531;
  --text: #e8ecf3;
  --text-muted: #8993a8;
  --text-faint: #5c6478;
  --accent: #f2a950;
  --accent-strong: #ffbf6e;
  --accent-soft: rgba(242, 169, 80, 0.14);
  --mint: #5fd9a4;
  --mint-soft: rgba(95, 217, 164, 0.14);
  --danger: #e8607a;
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --topbar-h: 64px;
  --sidebar-w: 248px;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --font-sans: 'Noto Sans JP', system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
}

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

button {
  font-family: inherit;
  cursor: pointer;
}

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

/* ---------- Topbar ---------- */

.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: rgba(23, 29, 40, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.hamburger {
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--panel-alt);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  transition: border-color .15s ease, background .15s ease;
}

.hamburger:hover { border-color: var(--accent); }

.hamburger span {
  width: 16px;
  height: 2px;
  background: var(--text-muted);
  border-radius: 2px;
  transition: transform .25s ease, opacity .2s ease, background .2s ease;
}

.hamburger.active span { background: var(--accent); }
.hamburger.active span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.brand {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: .02em;
}

.brand strong { color: var(--text); }

.topbar-right {
  display: flex;
  align-items: center;
  gap: 18px;
}

.datetime {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
}

.streak {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  background: var(--accent-soft);
  border: 1px solid rgba(242, 169, 80, 0.3);
  padding: 5px 10px;
  border-radius: 999px;
  white-space: nowrap;
}

.streak strong {
  color: var(--accent-strong);
  font-weight: 700;
}

.avatar {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--panel-raised);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-strong);
}

.avatar svg { width: 18px; height: 18px; }

/* ---------- Auth (Googleログイン) ---------- */

.auth-area {
  display: flex;
  align-items: center;
}

#googleSignInDiv {
  line-height: 0;
}

.google-login-btn {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  color: #1a1206;
  background: var(--accent);
  padding: 8px 16px;
  border-radius: 999px;
  display: inline-block;
  transition: background .15s ease;
}

.google-login-btn:hover {
  background: var(--accent-strong);
}

.user-menu {
  display: flex;
  align-items: center;
  gap: 10px;
}

.avatar-img {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--border);
  object-fit: cover;
}

.logout-btn {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--text-muted);
  background: var(--panel-alt);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 999px;
  transition: border-color .15s ease, color .15s ease;
}

.logout-btn:hover {
  border-color: var(--danger);
  color: var(--danger);
}

/* ---------- Sidebar ---------- */

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(6, 8, 12, 0.55);
  opacity: 0;
  pointer-events: none;
  transition: opacity .25s ease;
  z-index: 150;
}

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

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--sidebar-w);
  background: var(--panel);
  border-right: 1px solid var(--border);
  transform: translateX(-100%);
  transition: transform .28s cubic-bezier(.4,0,.2,1);
  z-index: 200;
  padding: 20px 0;
  display: flex;
  flex-direction: column;
}

.sidebar.active { transform: translateX(0); }

.sidebar-header {
  padding: 0 20px 18px;
  margin-bottom: 8px;
  border-bottom: 1px solid var(--border-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-faint);
}

.sidebar nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 8px 10px;
}

.sidebar nav a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 12px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-muted);
  transition: background .15s ease, color .15s ease;
}

.sidebar nav a .prompt { color: var(--text-faint); }

.sidebar nav a:hover {
  background: var(--panel-alt);
  color: var(--text);
}

.sidebar nav a.active {
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.sidebar nav a.active .prompt { color: var(--accent-strong); }

/* ---------- Layout shell ---------- */

.page {
  padding-top: var(--topbar-h);
  min-height: 100vh;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 40px 24px 64px;
}

.page-heading {
  margin-bottom: 24px;
}

.page-heading h1 {
  font-size: 20px;
  margin: 0 0 4px;
}

.page-heading p {
  margin: 0;
  color: var(--text-muted);
  font-size: 13px;
}

/* ---------- Cards / panels ---------- */

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
}

.panel h2 {
  font-size: 15px;
  margin: 0 0 18px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.panel h2::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  display: inline-block;
}

/* ---------- Empty state ---------- */

.empty-state {
  padding: 48px 20px;
  text-align: center;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  background: var(--panel-alt);
}

.terminal-line {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 15px;
  margin: 0 0 10px;
}

.cursor {
  display: inline-block;
  animation: blink 1.1s step-end infinite;
}

@keyframes blink {
  0%, 50% { opacity: 1; }
  50.01%, 100% { opacity: 0; }
}

.empty-sub {
  margin: 0;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.7;
}

/* ---------- Responsive ---------- */

/* ---------- Problem list ---------- */

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  margin-bottom: 24px;
  padding: 16px 20px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.filter-label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--text-faint);
  letter-spacing: .04em;
}

.filter-buttons {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.filter-btn {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  background: var(--panel-alt);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 999px;
  transition: border-color .15s ease, color .15s ease, background .15s ease;
}

.filter-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.filter-btn.active {
  background: var(--accent-soft);
  border-color: rgba(242, 169, 80, 0.4);
  color: var(--accent-strong);
}

.badge-lang {
  color: var(--text);
  background: var(--panel-raised);
  border-color: var(--border);
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 18px;
}

.problem-card {
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px;
  transition: border-color .15s ease, transform .15s ease;
}

.problem-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card-badges {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.badge {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .03em;
  padding: 4px 9px;
  border-radius: 999px;
  border: 1px solid;
  white-space: nowrap;
}

.badge-tag {
  color: var(--mint);
  background: var(--mint-soft);
  border-color: rgba(95, 217, 164, 0.3);
}

.badge-diff-初級 {
  color: var(--text-muted);
  background: var(--panel-alt);
  border-color: var(--border);
}

.badge-diff-中級 {
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-color: rgba(242, 169, 80, 0.3);
}

.badge-diff-上級 {
  color: var(--danger);
  background: rgba(232, 96, 122, 0.12);
  border-color: rgba(232, 96, 122, 0.3);
}

.badge-solved {
  color: var(--mint);
  background: var(--mint-soft);
  border-color: rgba(95, 217, 164, 0.35);
}

.problem-card.is-solved {
  border-color: rgba(95, 217, 164, 0.35);
}

.problem-card h3 {
  font-size: 15.5px;
  margin: 0 0 8px;
}

.problem-card p {
  margin: 0;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.7;
  flex: 1;
}

.card-link {
  margin-top: 18px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.problem-card:hover .card-link { color: var(--accent-strong); }

.breadcrumb {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-muted);
  margin-bottom: 18px;
  transition: color .15s ease;
}

.breadcrumb:hover { color: var(--accent); }

/* ---------- Problem page ---------- */

.problem-layout {
  display: grid;
  grid-template-columns: minmax(0, 380px) 1fr;
  gap: 24px;
  align-items: start;
}

.problem-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--mint);
  background: var(--mint-soft);
  border: 1px solid rgba(95, 217, 164, 0.3);
  padding: 4px 9px;
  border-radius: 999px;
  margin-bottom: 14px;
}

.problem-title {
  font-size: 18px;
  margin: 0 0 12px;
}

.problem-desc {
  color: var(--text-muted);
  font-size: 13.5px;
  line-height: 1.8;
  margin: 0 0 22px;
}

.subheading {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-faint);
  letter-spacing: .06em;
  text-transform: uppercase;
  margin: 0 0 10px;
}

.code-block {
  background: var(--panel-alt);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 16px 18px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.75;
  color: var(--text-muted);
  overflow-x: auto;
  margin: 0;
}

.code-block .tag { color: var(--accent-strong); }
.code-block .attr { color: var(--mint); }
.code-block .str { color: #a9b6cc; }

.editor-preview {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.editor-panel textarea {
  width: 100%;
  min-height: 220px;
  resize: vertical;
  background: var(--panel-alt);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
  padding: 16px 18px;
  tab-size: 2;
  transition: border-color .15s ease;
}

.editor-panel textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.editor-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 16px;
}

.run-btn {
  background: var(--accent);
  color: #1a1206;
  border: none;
  font-weight: 700;
  font-size: 13px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  transition: background .15s ease, transform .1s ease;
}

.run-btn:hover { background: var(--accent-strong); }
.run-btn:active { transform: scale(.97); }

.status-msg {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--mint);
  opacity: 0;
  transition: opacity .2s ease;
}

.status-msg.show { opacity: 1; }
.status-msg.error { color: var(--danger); }

.test-result {
  margin-top: 14px;
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  line-height: 1.6;
  display: none;
  border: 1px solid transparent;
}

.test-result.show { display: block; }

.test-result.test-pass {
  background: var(--mint-soft);
  border-color: rgba(95, 217, 164, 0.35);
  color: var(--mint);
}

.test-result.test-fail {
  background: rgba(232, 96, 122, 0.1);
  border-color: rgba(232, 96, 122, 0.3);
  color: var(--danger);
}

.preview-panel iframe {
  width: 100%;
  height: 240px;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  background: #ffffff;
}

/* ---------- AI Review ---------- */

.ai-review-desc {
  color: var(--text-muted);
  font-size: 12.5px;
  line-height: 1.7;
  margin: 0 0 16px;
}

.ai-review-btn {
  background: var(--panel-raised);
  color: var(--text);
  border: 1px solid var(--border);
  font-weight: 600;
  font-size: 13px;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  transition: border-color .15s ease, background .15s ease;
}

.ai-review-btn:hover:not(:disabled) {
  border-color: var(--accent);
}

.ai-review-btn:disabled {
  opacity: 0.6;
  cursor: default;
}

.ai-review-result {
  display: none;
  margin-top: 18px;
}

.ai-review-result.show {
  display: block;
}

.ai-review-result.error {
  color: var(--danger);
  font-size: 13px;
}

.ai-review-text {
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.8;
  margin: 0 0 18px;
}

.ai-review-result .code-block {
  margin-bottom: 18px;
}

/* ---------- IO Problems (AtCoder方式) ---------- */

.io-sample {
  margin-bottom: 8px;
}

.io-loading {
  color: var(--text-muted);
  font-size: 13px;
  font-family: var(--font-mono);
}

.io-cases {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.io-case {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.io-case-pass {
  border-color: rgba(95, 217, 164, 0.35);
}

.io-case-fail {
  border-color: rgba(232, 96, 122, 0.35);
}

.io-case-header {
  display: flex;
  justify-content: space-between;
  padding: 8px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
}

.io-case-pass .io-case-header {
  background: var(--mint-soft);
  color: var(--mint);
}

.io-case-fail .io-case-header {
  background: rgba(232, 96, 122, 0.1);
  color: var(--danger);
}

.io-case-body {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
  padding: 12px 14px;
  background: var(--panel-alt);
}

.io-case-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--text-faint);
  margin-bottom: 4px;
}

.io-case-body pre {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  white-space: pre-wrap;
  word-break: break-all;
}

@media (max-width: 860px) {
  .problem-layout { grid-template-columns: 1fr; }
}

/* ---------- History page ---------- */

.history-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  transition: border-color .15s ease;
}

.history-item:hover {
  border-color: var(--accent);
}

.history-item-main {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.history-item-main h3 {
  font-size: 14px;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.history-item-date {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-faint);
  white-space: nowrap;
}

/* ---------- Settings page ---------- */

.account-panel {
  display: flex;
  align-items: center;
  gap: 20px;
}

.account-avatar {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  border: 1px solid var(--border);
  object-fit: cover;
  flex-shrink: 0;
}

.account-info {
  flex: 1;
  min-width: 0;
}

.account-info h3 {
  font-size: 16px;
  margin: 0 0 4px;
}

.account-email {
  margin: 0 0 8px;
  color: var(--text-muted);
  font-size: 13px;
}

.account-streak {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-muted);
}

.account-streak strong {
  color: var(--accent-strong);
}

.logout-btn-large {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-muted);
  background: var(--panel-alt);
  border: 1px solid var(--border);
  padding: 10px 18px;
  border-radius: 999px;
  transition: border-color .15s ease, color .15s ease;
  flex-shrink: 0;
}

.logout-btn-large:hover {
  border-color: var(--danger);
  color: var(--danger);
}

@media (max-width: 640px) {
  .datetime { display: none; }
  .container { padding: 28px 16px 48px; }
}

/* ---------- Onboarding (初回ログイン時のスライド) ---------- */

.onboarding-overlay {
  position: fixed;
  inset: 0;
  background: rgba(6, 8, 12, 0.75);
  backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 500;
  padding: 20px;
}

.onboarding-card {
  position: relative;
  width: 100%;
  max-width: 440px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px 32px 28px;
  text-align: center;
}

.onboarding-skip {
  position: absolute;
  top: 16px;
  right: 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--text-faint);
  background: none;
  border: none;
  padding: 4px 8px;
  transition: color .15s ease;
}

.onboarding-skip:hover { color: var(--text-muted); }

.onboarding-title {
  font-size: 19px;
  margin: 8px 0 14px;
}

.onboarding-body {
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.8;
  margin: 0 0 28px;
  min-height: 76px;
}

.onboarding-dots {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-bottom: 26px;
}

.onboarding-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--border);
  transition: background .2s ease, transform .2s ease;
}

.onboarding-dot.active {
  background: var(--accent);
  transform: scale(1.3);
}

.onboarding-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.onboarding-prev {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--text-muted);
  background: none;
  border: none;
  padding: 8px 4px;
}

.onboarding-prev:hover { color: var(--text); }

.onboarding-next {
  background: var(--accent);
  color: #1a1206;
  border: none;
  font-weight: 700;
  font-size: 13px;
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  transition: background .15s ease;
}

.onboarding-next:hover { background: var(--accent-strong); }