:root {
  --color-bg: #f7f8fa;
  --color-surface: #ffffff;
  --color-border: #dde1e6;
  --color-text: #1b1f24;
  --color-muted: #5b6572;
  --color-primary: #1f6feb;
  --color-primary-dark: #1554b8;
  --color-passed: #1a7f37;
  --color-passed-bg: #ddf4e4;
  --color-failed: #b42318;
  --color-failed-bg: #fde8e6;
  --color-running: #9a6700;
  --color-running-bg: #fff3cd;
  --radius: 8px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
}

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.site-title {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  text-decoration: none;
}

.site-user {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.site-user a {
  color: var(--color-primary);
  text-decoration: none;
}

.site-user a:hover { text-decoration: underline; }

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem;
}

.site-footer {
  max-width: 900px;
  margin: 2rem auto;
  padding: 1rem 1.5rem;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.site-footer-links {
  margin-top: 0.5rem;
}

.site-footer-links a {
  color: var(--color-primary);
  text-decoration: none;
}

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

h1 { font-size: 1.6rem; }
h2 { font-size: 1.2rem; margin-top: 2rem; }

.category-heading {
  margin-top: 2.5rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.4rem;
}

.exercise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.exercise-card, .panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.panel { margin-bottom: 1.5rem; }

.exercise-card { position: relative; }
.exercise-card h3 { margin-top: 0; padding-right: 5.5rem; }

.hint {
  color: var(--color-muted);
  font-size: 0.92rem;
}

.exercise-instructions { margin: 0.4rem 0 0.75rem; font-size: 0.92rem; }
.exercise-instructions a { color: var(--color-primary); text-decoration: none; }
.exercise-instructions a:hover { text-decoration: underline; }

.type-tag {
  position: absolute;
  top: 1.1rem;
  right: 1.25rem;
  text-transform: capitalize;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  background: #eceff3;
  color: var(--color-muted);
}
.type-tag-additional { background: #eef2ff; color: #4338ca; }

.score-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1rem 0 2rem;
}

.score-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.score-label {
  flex: 1 1 auto;
  font-weight: 600;
  font-size: 0.95rem;
}

.score-value { color: var(--color-muted); font-size: 0.95rem; }

.score-percentage {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-primary);
}

.exercise-status { margin: 0.75rem 0; }

.badge {
  display: inline-block;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
}

.badge-passed { background: var(--color-passed-bg); color: var(--color-passed); }
.badge-not-completed { background: #eceff3; color: var(--color-muted); }
.badge-running { background: var(--color-running-bg); color: var(--color-running); }
.badge-error { background: var(--color-failed-bg); color: var(--color-failed); }

.submission-count {
  margin-left: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-muted);
}

.exercise-actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.button {
  display: inline-block;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  border: 1px solid transparent;
  cursor: pointer;
}

.button-primary { background: var(--color-primary); color: #fff; }
.button-primary:hover { background: var(--color-primary-dark); }
.button-secondary { background: var(--color-surface); color: var(--color-primary); border-color: var(--color-primary); }

.login-form { max-width: 360px; }
.login-form label { display: block; font-weight: 600; font-size: 0.9rem; margin-bottom: 0.25rem; }
.login-form input[type="text"], .login-form input[type="password"] {
  width: 100%;
  padding: 0.5rem;
  margin-bottom: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font: inherit;
}

.file-table { width: 100%; border-collapse: collapse; margin: 1rem 0; }
.file-table td { padding: 0.4rem 0.2rem; border-bottom: 1px solid var(--color-border); }
.file-table-name { width: 40%; }

.banner {
  padding: 0.9rem 1.1rem;
  border-radius: var(--radius);
  margin: 1rem 0;
}
.banner-error { background: var(--color-failed-bg); color: var(--color-failed); }

.status-passed { border-left: 4px solid var(--color-passed); }
.status-failed { border-left: 4px solid var(--color-failed); }
.status-running { border-left: 4px solid var(--color-running); }
.status-error { border-left: 4px solid var(--color-failed); }

.loading-panel { text-align: center; }
.loading-panel p { color: var(--color-muted); margin-bottom: 0; }

.progress-bar {
  height: 8px;
  border-radius: 999px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  margin-bottom: 1rem;
}
.progress-bar-fill {
  height: 100%;
  width: 40%;
  border-radius: 999px;
  background: var(--color-primary);
  animation: progress-bar-indeterminate 1.4s ease-in-out infinite;
}
@keyframes progress-bar-indeterminate {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(250%); }
}

#warmup-error { text-align: center; }
#warmup-error p { margin-top: 0; }

.check-list { list-style: none; margin: 0; padding: 0; }
.check-item { padding: 0.6rem 0; border-bottom: 1px solid var(--color-border); }
.check-item:last-child { border-bottom: none; }
.check-icon { display: inline-block; width: 1.4rem; font-weight: 700; }
.check-passed .check-icon { color: var(--color-passed); }
.check-failed .check-icon { color: var(--color-failed); }
.check-detail {
  margin-left: 1.4rem;
  margin-top: 0.35rem;
  font-size: 0.9rem;
  color: var(--color-muted);
}
.check-detail code { background: #f0f2f5; padding: 0.1rem 0.3rem; border-radius: 4px; }

.raw-output {
  white-space: pre-wrap;
  word-break: break-word;
  background: #0d1117;
  color: #d7dee6;
  padding: 1rem;
  border-radius: var(--radius);
  max-height: 400px;
  overflow: auto;
  font-size: 0.85rem;
}

.history-list { list-style: none; margin: 0; padding: 0; }
.history-list li { padding: 0.4rem 0; border-bottom: 1px solid var(--color-border); }
.history-list a { color: var(--color-text); text-decoration: none; }
.history-list a:hover { text-decoration: underline; }

@media (max-width: 640px) {
  .exercise-grid { grid-template-columns: 1fr; }
  .file-table-name { width: auto; }
}