:root {
  --card: #ffffff;
  --text: #1f2937;
  --muted: #3f4146;
  --primary: #1d4ed8;
  --primary-soft: #dbeafe;
  --border: #dbe3ef;
  --shadow: 0 14px 35px rgba(15, 23, 42, 0.08);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background: #5d5d61;
  color: var(--text);
  line-height: 1.6;
}

img {
  max-width: 100%;
  display: block;
}

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

a:hover {
  text-decoration: underline;
}

.page-shell {
  width: min(1150px, calc(100% - 40px));
  margin: 40px auto;
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 24px;
}

.sidebar,
.section-card {
  background: var(--card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  border-radius: 22px;
}

.sidebar {
  padding: 28px;
  position: sticky;
  top: 20px;
  align-self: start;
}

.profile-card {
  text-align: center;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.profile-image {
  width: 150px;
  height: 150px;
  object-fit: cover;
  margin: 0 auto 18px;
  border-radius: 50%;
  border: 5px solid #587b9e;
  background: #f9fbff;
}

h1 {
  font-size: 2rem;
  line-height: 1.2;
  margin-bottom: 8px;
}

.title {
  color: var(--muted);
  font-weight: 700;
}

.sidebar-section {
  margin-top: 26px;
}

.sidebar-nav {
  margin-top: 20px;
}

.sidebar-nav ul {
  list-style: none;
  padding: 0;
}

.sidebar-nav li + li {
  margin-top: 10px;
}

.nav-link {
  color: var(--text);
  font-weight: 700;
  cursor: pointer;
  padding: 8px 12px;
  display: block;
  border-radius: 6px;
  transition: background 0.3s ease, color 0.3s ease;
}

.nav-link:hover,
.nav-link.active-link {
  background: var(--primary-soft);
  text-decoration: none;
}

.sidebar-section h2,
.hero h2,
.timeline-head h3,
.mini-card h3 {
  line-height: 1.3;
}

.sidebar-section h2 {
  font-size: 1.1rem;
  margin-bottom: 14px;
}

.contact-list,
.tag-list {
  list-style: none;
}

.contact-list li {
  margin-bottom: 10px;
  color: var(--muted);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag-list li {
  background: var(--primary-soft);
  color: #1e3a8a;
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 0.92rem;
  font-weight: 700;
}

.main-content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.section-card {
  padding: 30px;
}

.section-label {
  color: var(--primary);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.82rem;
  margin-bottom: 10px;
}

.hero h2 {
  font-size: 2rem;
  margin-bottom: 14px;
}

.hero p:last-child,
.timeline-item p,
.mini-card p,
.subtitle {
  color: var(--muted);
}

.timeline-item + .timeline-item {
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.timeline-head {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: baseline;
  margin-bottom: 8px;
}

.timeline-head span {
  color: var(--primary);
  font-weight: 700;
  white-space: nowrap;
}

.subtitle {
  font-weight: 700;
  margin-bottom: 8px;
}

.grid-two {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.mini-card {
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px;
  background: #fbfdff;
}

/* Assignment 2 additions */
.section-heading-with-action {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px; /* adds breathing room */
  flex-wrap: wrap;
  margin-bottom: 12px; /* space below header */
}

.main-section-header .section-label {
  margin-bottom: 0;
}

.hero-top-bar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 14px;
}

.action-btn,
.mode-toggle-btn,
.project-details-btn,
.submit-btn {
  border: 1px solid var(--border);
  background: #eef4ff;
  color: #1e3a8a;
  padding: 9px 14px;
  border-radius: 12px;
  font-weight: 700;
  cursor: pointer;
  transition: 0.2s ease;
}
.action-btn,
.mode-toggle-btn,
.project-details-btn {
  margin-top: 4px;
}

.action-btn {
  margin-left: auto;
}

.action-btn:hover,
.mode-toggle-btn:hover,
.project-details-btn:hover,
.submit-btn:hover {
  background: #dbeafe;
}

.mode-toggle-btn {
  white-space: nowrap;
}

.form-group input,
.form-group textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 14px;
  font: inherit;
  color: var(--text);
  background: #ffffff;
}

.welcome-message {
  margin-top: 16px;
  font-weight: 700;
  color: var(--primary);
  display: none;
}

.github-loading {
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
}

.github-status {
  color: var(--muted);
  font-weight: 700;
  margin-bottom: 12px;
}

.github-status.success {
  color: #166534;
}

.github-status.warning {
  color: #92400e;
}

.github-repo-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 16px;
  min-height: 210px;
}

.github-repo-card h3 {
  word-break: break-word;
}

.github-repo-card p {
  font-size: 0.9rem;
  margin-top: 8px;
}

.repo-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.repo-language,
.repo-stars {
  display: inline-block;
  background: var(--primary-soft);
  color: var(--primary);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 700;
}

.repo-card-actions {
  margin-top: 14px;
}

.repo-card-actions .action-btn {
  display: block;
  margin-left: 0;
  text-align: center;
  width: 100%;
}

.project-details {
  display: none;
  margin-top: 14px;
  padding: 16px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: #fbfdff;
}

.project-details.open {
  display: block;
}

.form-group + .form-group {
  margin-top: 16px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 700;
}

.submit-btn {
  margin-top: 18px;
}

.form-message {
  margin-top: 14px;
  font-weight: 700;
  display: none;
}

.form-message.error {
  color: #b91c1c;
  display: block;
}

.form-message.success {
  color: #166534;
  display: block;
}

.hidden-section {
  display: none;
}

/* Dark mode */
body.dark-mode {
  --card: #111827;
  --text: #f3f4f6;
  --muted: #cfd6df;
  --primary: #93c5fd;
  --primary-soft: #1e3a8a;
  --border: #2b3647;
  --shadow: 0 14px 35px rgba(0, 0, 0, 0.25);
  background: #0b1120;
}

body.dark-mode .mini-card,
body.dark-mode .project-details,
body.dark-mode .form-group input,
body.dark-mode .form-group textarea {
  background: #0f172a;
}


body.dark-mode .tag-list li {
  background: #1e3a8a;
  color: #f8fbff;
}

body.dark-mode .nav-link.active-link,
body.dark-mode .nav-link:hover {
  background: #1e3a8a;
  color: #f8fbff;
}

body.dark-mode .github-status.success {
  color: #86efac;
}

body.dark-mode .github-status.warning {
  color: #fbbf24;
}

body.dark-mode .repo-language,
body.dark-mode .repo-stars {
  background: #172554;
  color: #93c5fd;
}

body.dark-mode .action-btn,
body.dark-mode .mode-toggle-btn,
body.dark-mode .project-details-btn,
body.dark-mode .submit-btn {
  background: #172554;
  color: #dbeafe;
}

body.dark-mode .action-btn:hover,
body.dark-mode .mode-toggle-btn:hover,
body.dark-mode .project-details-btn:hover,
body.dark-mode .submit-btn:hover {
  background: #1d4ed8;
}

@media (max-width: 920px) {
  .page-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  .hero-top-bar {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 620px) {
  .page-shell {
    width: min(100% - 24px, 1000px);
    margin: 20px auto;
  }

  .section-card,
  .sidebar {
    padding: 22px;
  }

  h1,
  .hero h2 {
    font-size: 1.65rem;
  }

  .timeline-head,
  .grid-two {
    grid-template-columns: 1fr;
    display: grid;
  }

  .timeline-head span {
    white-space: normal;
  }

  .section-heading-with-action {
    align-items: flex-start;
  }
}