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

:root {
  --sidebar-w: 210px;
  --navy:   #1a2540;
  --navy2:  #243050;
  --navy3:  #2e3d63;
  --accent: #4f8ef7;
  --accent2:#6ba3ff;
  --green:  #22c55e;
  --green-bg: #f0fdf4;
  --green-bd: #bbf7d0;
  --red:    #ef4444;
  --red-bg: #fef2f2;
  --red-bd: #fecaca;
  --orange: #f97316;
  --orange-bg: #fff7ed;
  --orange-bd: #fed7aa;
  --yellow-bg: #fefce8;
  --yellow-bd: #fef08a;
  --gray:   #6b7280;
  --gray-light: #f3f4f6;
  --gray-mid:   #e5e7eb;
  --text:   #111827;
  --text2:  #374151;
  --text3:  #6b7280;
  --radius: 10px;
  --shadow: 0 2px 8px rgba(0,0,0,.10);
}

html, body {
  height: 100%;
  font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
  font-size: 14px;
  color: var(--text);
  background: var(--gray-light);
}

/* ── Layout ───────────────────────────────────────────────────────────── */
.layout {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

/* ── Sidebar ──────────────────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  background: var(--navy);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 22px 16px 18px;
  border-bottom: 1px solid var(--navy3);
}
.brand-icon { font-size: 28px; line-height: 1; }
.brand-text { display: flex; flex-direction: column; }
.brand-title {
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: .02em;
}
.brand-sub {
  color: var(--accent2);
  font-size: 10px;
  margin-top: 3px;
  letter-spacing: .03em;
}

.problem-nav {
  flex: 1;
  padding: 10px 8px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 9px 10px;
  border: none;
  border-radius: 7px;
  background: transparent;
  color: #c8d6f0;
  cursor: pointer;
  text-align: left;
  transition: background .15s, color .15s;
}
.nav-btn:hover { background: var(--navy2); color: #fff; }
.nav-btn.active { background: var(--accent); color: #fff; }

.nav-num {
  font-size: 11px;
  font-weight: 700;
  opacity: .6;
  min-width: 22px;
}
.nav-btn.active .nav-num { opacity: .85; }

.nav-name { font-size: 12.5px; font-weight: 500; flex: 1; }

.nav-score {
  font-size: 11px;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: 20px;
  background: rgba(255,255,255,.15);
  color: #fff;
  display: none;
}
.nav-score.all-pass  { display: inline; background: var(--green); }
.nav-score.some-pass { display: inline; background: var(--orange); }
.nav-score.all-fail  { display: inline; background: var(--red); }

.sidebar-footer {
  padding: 12px 14px;
  border-top: 1px solid var(--navy3);
}
.java-check {
  font-size: 11px;
  color: #8ba3cc;
}
.java-check.ok   { color: #6ee7b7; }
.java-check.warn { color: #fcd34d; }

/* ── Main content ─────────────────────────────────────────────────────── */
.main {
  flex: 1;
  overflow-y: auto;
  padding: 28px 32px;
}

/* ── Problem panels ───────────────────────────────────────────────────── */
.panel { display: none; max-width: 820px; }
.panel.active { display: block; }

.panel-header {
  margin-bottom: 22px;
}
.panel-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: .06em;
  margin-bottom: 4px;
}
.panel-title {
  font-size: 26px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 4px;
}
.panel-sub {
  font-size: 14px;
  color: var(--text3);
}

/* ── Upload card ──────────────────────────────────────────────────────── */
.upload-card {
  background: #fff;
  border: 1px solid var(--gray-mid);
  border-radius: var(--radius);
  padding: 20px 22px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

.upload-instructions {
  margin-bottom: 16px;
}
.upload-instructions p {
  color: var(--text2);
  margin-bottom: 8px;
  line-height: 1.55;
}
.upload-instructions ul {
  padding-left: 20px;
  color: var(--text2);
  line-height: 1.65;
}
.upload-instructions code {
  background: var(--gray-light);
  border: 1px solid var(--gray-mid);
  padding: 1px 5px;
  border-radius: 4px;
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: 12.5px;
  color: var(--navy);
}
.note-box {
  margin-top: 12px !important;
  background: var(--yellow-bg);
  border: 1px solid var(--yellow-bd);
  border-radius: 7px;
  padding: 10px 14px;
  font-size: 13px;
  color: #78350f;
}
.note-box code {
  background: rgba(0,0,0,.05) !important;
  border-color: transparent !important;
}

.upload-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

/* Hidden real file input */
.file-input { display: none; }

.file-label {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  background: var(--gray-light);
  border: 1.5px dashed var(--gray-mid);
  border-radius: 8px;
  cursor: pointer;
  color: var(--text2);
  font-size: 13px;
  transition: border-color .15s, background .15s;
  flex: 1;
  min-width: 200px;
  max-width: 340px;
}
.file-label:hover {
  border-color: var(--accent);
  background: #eff6ff;
  color: var(--accent);
}
.file-icon { font-size: 16px; }
.file-text { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.grade-btn {
  padding: 9px 22px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s, opacity .15s;
  white-space: nowrap;
}
.grade-btn:hover:not(:disabled) { background: #3a7be0; }
.grade-btn:disabled { opacity: .45; cursor: not-allowed; }

/* ── Loading ──────────────────────────────────────────────────────────── */
.loading {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text3);
  padding: 20px 0;
  font-size: 14px;
}
.spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2.5px solid var(--gray-mid);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Error boxes ──────────────────────────────────────────────────────── */
.error-box {
  background: var(--red-bg);
  border: 1px solid var(--red-bd);
  border-radius: 8px;
  padding: 14px 16px;
  color: #991b1b;
  font-size: 13.5px;
}

.compile-error {
  background: var(--orange-bg);
  border: 1px solid var(--orange-bd);
  border-radius: 8px;
  padding: 16px 18px;
}
.compile-title {
  font-weight: 600;
  color: #7c2d12;
  margin-bottom: 10px;
  font-size: 14px;
}
.error-pre {
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: 12px;
  color: #431407;
  white-space: pre-wrap;
  word-break: break-word;
  background: rgba(0,0,0,.04);
  border-radius: 6px;
  padding: 10px 12px;
  max-height: 280px;
  overflow-y: auto;
}

/* ── Results ──────────────────────────────────────────────────────────── */
.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
  flex-wrap: wrap;
  gap: 8px;
}
.class-name {
  font-size: 13px;
  color: var(--text3);
}
.class-name code {
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  color: var(--text2);
  font-size: 13px;
}
.score-badge {
  padding: 4px 14px;
  border-radius: 20px;
  font-weight: 700;
  font-size: 13px;
}
.score-badge.all-pass  { background: var(--green-bg);  color: #166534; border: 1px solid var(--green-bd); }
.score-badge.some-pass { background: var(--orange-bg); color: #7c2d12; border: 1px solid var(--orange-bd); }
.score-badge.all-fail  { background: var(--red-bg);    color: #991b1b; border: 1px solid var(--red-bd); }

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

.test-item {
  border-radius: 9px;
  overflow: hidden;
  border: 1px solid var(--gray-mid);
  background: #fff;
  box-shadow: 0 1px 3px rgba(0,0,0,.06);
}
.test-item.pass { border-color: var(--green-bd); }
.test-item.fail { border-color: var(--red-bd); }

.test-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  font-size: 13.5px;
  font-weight: 600;
}
.test-item.pass .test-header { background: var(--green-bg); color: #166534; }
.test-item.fail .test-header { background: var(--red-bg);   color: #991b1b; }

.test-icon { font-size: 15px; font-weight: 900; }
.test-num  { font-size: 11px; opacity: .7; min-width: 44px; }
.test-desc { flex: 1; }

.badge {
  font-size: 10px;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.badge.timeout {
  background: var(--yellow-bg);
  border: 1px solid var(--yellow-bd);
  color: #78350f;
}

.test-body {
  padding: 10px 14px 12px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.test-row {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 12.5px;
}
.test-row .label {
  min-width: 88px;
  font-weight: 600;
  color: var(--text3);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .04em;
}
.test-row .val {
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: 12px;
  color: var(--text2);
  background: var(--gray-light);
  border: 1px solid var(--gray-mid);
  padding: 2px 8px;
  border-radius: 4px;
  word-break: break-all;
  max-width: 560px;
  overflow-wrap: anywhere;
}
.test-row .val.ok  { background: var(--green-bg); border-color: var(--green-bd); color: #14532d; }
.test-row .val.bad { background: var(--red-bg);   border-color: var(--red-bd);   color: #7f1d1d; }

.test-note {
  font-size: 12px;
  color: var(--text3);
  margin-top: 2px;
  font-style: italic;
  padding-left: 96px;
}
.test-item.fail .test-note { color: #b91c1c; }
.test-item.pass .test-note { color: #15803d; font-style: normal; }

/* ── Scrollbar styling ────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--gray-mid); border-radius: 3px; }