/* Shared demo styles */
:root {
        --bg: #f4f7fb;
        --card: #ffffff;
        --ink: #13233a;
        --accent: #0d6efd;
        --success: #198754;
        --border: #d9e2ef;
        --primary: #053660;
      }

      * {
        box-sizing: border-box;
      }

      body {
        margin: 0;
        font-family: "Segoe UI", Tahoma, sans-serif;
        background: linear-gradient(135deg, #f4f7fb 0%, #e8f1ff 100%);
        color: var(--ink);
        padding: 24px;
      }

      .wrap {
        max-width: 1000px;
        margin: 0 auto;
      }

      .brand-bar {
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 16px;
        margin-bottom: 10px;
      }

      .brand-logo-main {
        width: 88px;
        height: 88px;
        object-fit: contain;
        border-radius: 50%;
        background: transparent;
        border: 1px solid #c9d7ea;
        padding: 0;
      }

      .brand-logo-secondary {
        width: 56px;
        height: 56px;
        object-fit: contain;
        border-radius: 50%;
        background: transparent;
        border: 1px solid #c9d7ea;
        padding: 0;
      }

      .brand-secondary {
        display: flex;
        align-items: center;
        gap: 8px;
        color: #35557a;
        font-size: 12px;
        font-weight: 600;
        white-space: nowrap;
      }

      .brand-text {
        flex: 1;
        color: #1f3f64;
        line-height: 1.25;
      }

      .brand-title {
        display: block;
        font-size: 22px;
        font-weight: 700;
        letter-spacing: 0.2px;
      }

      .brand-subtitle {
        display: block;
        font-size: 16px;
        font-weight: 600;
        margin-top: 2px;
      }

      h1 {
        margin-bottom: 6px;
        color: var(--primary);
        font-size: 28px;
      }

      h2 {
        color: var(--primary);
        font-size: 18px;
        margin-top: 20px;
        margin-bottom: 12px;
      }

      .subtitle {
        margin-top: 0;
        color: #35557a;
        font-size: 14px;
      }

      .card {
        background: var(--card);
        border: 1px solid var(--border);
        border-radius: 12px;
        padding: 20px;
        margin: 16px 0;
        box-shadow: 0 8px 18px rgba(17, 58, 94, 0.08);
      }

      .demo-section {
        margin-bottom: 20px;
      }

      /* HTML Structure Demo */
      .profile-card {
        border: 2px dashed #0d6efd;
        padding: 15px;
        border-radius: 8px;
        background: #f0f6ff;
        margin: 12px 0;
      }

      .profile-header {
        font-size: 18px;
        font-weight: 600;
        color: var(--primary);
        margin-bottom: 10px;
      }

      .profile-info {
        list-style-position: inside;
        padding-left: 0;
        margin: 8px 0;
      }

      .profile-info li {
        margin: 6px 0;
        font-size: 14px;
      }

      /* CSS Styling Demo */
      .grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 12px;
        margin: 12px 0;
      }

      .tech-box {
        background: linear-gradient(135deg, #fff 0%, #f9f9f9 100%);
        border: 2px solid var(--border);
        border-radius: 8px;
        padding: 16px;
        text-align: center;
        font-weight: 600;
        transition: all 0.3s ease;
      }

      .tech-box:hover {
        transform: translateY(-4px);
        box-shadow: 0 6px 14px rgba(17, 58, 94, 0.15);
      }

      .tech-box.html {
        border-color: #ff6b6b;
        color: #ff6b6b;
      }

      .tech-box.css {
        border-color: #4d96ff;
        color: #4d96ff;
      }

      .tech-box.js {
        border-color: #ffd93d;
        color: #ffd93d;
      }

      /* JavaScript Interactivity */
      .input-group {
        margin: 12px 0;
      }

      label {
        display: block;
        font-weight: 600;
        margin-bottom: 6px;
        font-size: 14px;
      }

      input,
      button {
        padding: 10px 12px;
        border-radius: 6px;
        border: 1px solid #b9cce5;
        font-size: 14px;
      }

      input {
        width: 100%;
        margin-bottom: 8px;
      }

      button {
        cursor: pointer;
        border: none;
        background: var(--accent);
        color: #fff;
        font-weight: 600;
        width: 100%;
        margin: 8px 0;
        transition: all 0.3s ease;
      }

      button:hover {
        background: #0b5ed7;
        transform: scale(1.02);
      }

      button:active {
        transform: scale(0.98);
      }

      .output-section {
        background: #0e1a2b;
        color: #d7e6ff;
        padding: 16px;
        border-radius: 8px;
        font-family: "Courier New", monospace;
        font-size: 13px;
        min-height: 100px;
        margin-top: 12px;
        line-height: 1.6;
      }

      .success-message {
        background: #d4edda;
        color: #155724;
        padding: 12px;
        border-radius: 6px;
        border: 1px solid #c3e6cb;
        margin: 12px 0;
        display: none;
      }

      .success-message.show {
        display: block;
      }

      .code-block {
        background: #f5f5f5;
        border: 1px solid #ddd;
        padding: 12px;
        border-radius: 6px;
        font-family: "Courier New", monospace;
        font-size: 12px;
        overflow-x: auto;
        margin: 8px 0;
      }

      .pill {
        display: inline-block;
        background: #e8f1ff;
        color: #0d6efd;
        border: 1px solid #b9cce5;
        padding: 4px 10px;
        border-radius: 999px;
        font-size: 12px;
        margin-right: 6px;
        margin-bottom: 6px;
      }

      .tip {
        background: #fff3cd;
        border-left: 4px solid #ffc107;
        padding: 12px;
        border-radius: 4px;
        margin: 12px 0;
        font-size: 13px;
      }

      @media (max-width: 640px) {
        .brand-bar {
          align-items: flex-start;
          gap: 12px;
        }

        .brand-logo-main {
          width: 64px;
          height: 64px;
        }

        .brand-logo-secondary {
          width: 42px;
          height: 42px;
        }

        .brand-secondary {
          font-size: 10px;
          gap: 6px;
        }

        .brand-title {
          font-size: 18px;
        }

        .brand-subtitle {
          font-size: 13px;
        }
      }

/* Lecture 2 additions */
select {
  width: 100%;
  margin-bottom: 10px;
}

.timeline {
  background: #0f1f33;
  color: #e3edff;
  border-radius: 8px;
  padding: 14px;
  font-family: Consolas, "Courier New", monospace;
  font-size: 13px;
  line-height: 1.6;
  min-height: 160px;
}

.status {
  margin-top: 10px;
  font-weight: 600;
}

.ok {
  color: #198754;
}

.warn {
  color: #b54708;
}

/* Shared utilities for lecture 4-8 demos */
.code-inline,
code.c,
code.inline-code,
.code-small {
  background: #f0f0f0;
  border: 1px solid #ddd;
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 12px;
}

.pre-tight,
pre {
  white-space: pre-wrap;
}

pre.code-block {
  background: #f8f9fa;
  border: 1px solid #dee2e6;
  border-radius: 6px;
  padding: 12px;
  font-size: 12px;
  white-space: pre-wrap;
  margin: 8px 0;
}

.toggle-btn {
  background: #053660;
  color: #fff;
  border: none;
  padding: 8px 14px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  margin: 4px;
  width: auto;
}

.toggle-btn:hover {
  background: #0a58ca;
  transform: none;
}

.demo-list-card {
  background: #f8f9fa;
  border: 1px solid #dee2e6;
  border-radius: 8px;
  padding: 16px;
}

.demo-list-card h3 {
  color: #053660;
  margin: 0 0 8px;
}

.demo-list-card ul,
.demo-list-card ol,
.demo-list-card dl {
  margin: 0;
  padding-left: 20px;
  font-size: 14px;
  line-height: 1.8;
}

.demo-list-card dl {
  padding-left: 0;
}

.demo-list-card dt {
  font-weight: 700;
  color: #053660;
}

.demo-list-card dd {
  margin-left: 20px;
  color: #444;
}

.style-btn {
  border: none;
  padding: 6px 12px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 12px;
  margin: 2px;
  width: auto;
}

.alt-demo {
  background: #f8f9fa;
  border: 2px dashed #dee2e6;
  border-radius: 8px;
  padding: 20px;
  text-align: center;
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.link-type-card {
  border: 2px solid #dee2e6;
  border-radius: 8px;
  padding: 12px;
  transition: border-color 0.2s;
}

.link-type-card:hover {
  border-color: #0d6efd;
}

.link-type-card h3 {
  margin: 0 0 6px;
  font-size: 14px;
  color: #053660;
}

.result-box {
  background: #f0f6ff;
  border: 1px solid #a8c7fa;
  border-radius: 6px;
  padding: 10px;
  margin-top: 8px;
  font-size: 13px;
}

.image-attr-toggle {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 10px;
}

.image-attr-toggle label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  cursor: pointer;
}

.img-preview {
  border: 2px solid #dee2e6;
  border-radius: 8px;
  background: #f8f9fa;
  padding: 20px;
  text-align: center;
  min-height: 100px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.nav-demo {
  background: #f8f9fa;
  border: 1px solid #dee2e6;
  border-radius: 8px;
  padding: 8px;
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.nav-demo a {
  color: #053660;
  text-decoration: none;
  padding: 8px 12px;
  border-bottom: 2px solid transparent;
  font-size: 14px;
}

.nav-demo a:hover {
  border-bottom-color: #0d6efd;
  color: #0d6efd;
}

table.demo-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

table.demo-table th {
  background: #053660;
  color: #fff;
  padding: 8px 10px;
  text-align: left;
}

table.demo-table td {
  padding: 8px 10px;
  border-bottom: 1px solid #dee2e6;
}

table.demo-table tr:last-child td {
  border-bottom: none;
}

table.demo-table tr:nth-child(even) td {
  background: #f8f9fa;
}

table.demo-table caption {
  font-weight: 700;
  padding: 8px;
  font-size: 13px;
  color: #053660;
  caption-side: top;
  text-align: left;
}

table.demo-table tfoot td {
  background: #eef3f7;
  font-weight: 700;
}

.span-grid {
  border-collapse: collapse;
  font-size: 12px;
}

.span-grid td,
.span-grid th {
  border: 2px solid #053660;
  padding: 8px;
  text-align: center;
}

.span-grid th {
  background: #053660;
  color: #fff;
}

.scope-demo th[scope="col"] {
  background: #0a58ca;
}

.scope-demo th[scope="row"] {
  background: #1565c0;
}

.iframe-sandbox-box {
  background: #f8f9fa;
  border: 2px dashed #dee2e6;
  border-radius: 8px;
  padding: 16px;
  text-align: center;
  font-size: 13px;
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.form-demo {
  background: #f8f9fa;
  border: 1px solid #dee2e6;
  border-radius: 8px;
  padding: 16px;
}

.form-demo label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 4px;
  color: #053660;
}

.form-demo input[type="text"],
.form-demo input[type="email"],
.form-demo input[type="password"],
.form-demo input[type="number"],
.form-demo input[type="date"],
.form-demo input[type="url"],
.form-demo input[type="tel"],
.form-demo select,
.form-demo textarea {
  width: 100%;
  padding: 8px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 13px;
  box-sizing: border-box;
  margin-bottom: 12px;
}

.form-demo input[type="range"] {
  width: 100%;
  margin-bottom: 8px;
}

.form-demo fieldset {
  border: 2px solid #053660;
  border-radius: 8px;
  padding: 12px;
  margin-bottom: 12px;
}

.form-demo legend {
  color: #053660;
  font-weight: 700;
  font-size: 13px;
  padding: 0 6px;
}

.inline-inputs label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-right: 16px;
  font-weight: 400;
}

.data-preview {
  background: #eef3f7;
  border: 2px solid #053660;
  border-radius: 8px;
  padding: 14px;
  font-size: 13px;
  min-height: 50px;
}

.highlight-green {
  background: #e8f5e9 !important;
  border-color: #198754 !important;
}

.highlight-red {
  background: #fff3f3 !important;
  border-color: #dc3545 !important;
}

.label-demo .bad {
  background: #fff3f3;
  border: 1px solid #f5c2c7;
  border-radius: 6px;
  padding: 12px;
}

.label-demo .good {
  background: #f3fff3;
  border: 1px solid #c3e6c3;
  border-radius: 6px;
  padding: 12px;
}

.block-demo {
  background: #e7f3ff;
  border: 2px solid #0d6efd;
  padding: 10px;
  margin: 8px 0;
  border-radius: 6px;
  font-size: 13px;
}

.layout-header {
  background: #053660;
  color: #fff;
  padding: 10px;
  border-radius: 4px;
  margin-bottom: 8px;
  font-weight: 700;
}

.layout-content-area {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
}

.layout-main {
  flex: 1;
  background: #e8f4f8;
  padding: 10px;
  border-radius: 4px;
  border: 1px solid #0d6efd;
}

.layout-sidebar {
  width: 120px;
  background: #fff4e6;
  padding: 10px;
  border-radius: 4px;
  border: 1px solid #ff9800;
}

.layout-footer {
  background: #333;
  color: #fff;
  padding: 8px;
  border-radius: 4px;
  text-align: center;
}

.semantic-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.bad-code {
  background: #fff3f3;
  border: 1px solid #f5c2c7;
  border-radius: 6px;
  padding: 12px;
}

.good-code {
  background: #f3fff3;
  border: 1px solid #c3e6c3;
  border-radius: 6px;
  padding: 12px;
}

figure {
  margin: 8px 0;
  display: inline-block;
}

figcaption {
  font-size: 12px;
  text-align: center;
  color: #555;
  margin-top: 4px;
  font-style: italic;
}

.nested-demo ul,
.nested-demo ol {
  margin: 4px 0;
}