/* Reset and Variables */
:root {
  --sdi-bg-color: #fcfcfc;
  --sdi-text-color: #333333;
  --sdi-primary-color: #2c3e50;
  --sdi-secondary-color: #18bc9c;
  --sdi-link-color: #18bc9c;
  --sdi-border-color: #e2e2e2;
  --sdi-font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

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

body.sdi-body {
  font-family: var(--sdi-font-family);
  background-color: var(--sdi-bg-color);
  color: var(--sdi-text-color);
  line-height: 1.6;
}

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

a:hover {
  text-decoration: underline;
}

/* Header */
.sdi-header {
  background-color: var(--sdi-primary-color);
  color: #ffffff;
  padding: 20px 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  border-bottom: 4px solid var(--sdi-secondary-color);
}

.sdi-header-content {
  width: 100%;
  max-width: 1200px;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 20px;
}

.sdi-site-title {
  margin-bottom: 15px;
  font-size: 2.5rem;
  letter-spacing: 1px;
}

.sdi-site-title a {
  color: #ffffff;
}

.sdi-site-title a:hover {
  text-decoration: none;
  opacity: 0.9;
}

.sdi-nav {
  width: 100%;
}

.sdi-nav-list {
  list-style: none;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}

.sdi-nav-item {
  margin: 0 15px;
}

.sdi-nav-item a {
  color: #ffffff;
  font-size: 1.1rem;
  font-weight: 500;
  text-transform: uppercase;
  padding: 5px 0;
}

.sdi-nav-item a:hover {
  color: var(--sdi-secondary-color);
  text-decoration: none;
}

/* Wrapper and Main Layout (Flexbox) */
.sdi-wrapper {
  max-width: 1200px;
  margin: 40px auto;
  display: flex;
  flex-wrap: wrap;
  padding: 0 20px;
  gap: 40px;
}

.sdi-main {
  flex: 1 1 700px;
  background-color: #ffffff;
  padding: 30px;
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.sdi-aside {
  flex: 0 1 320px;
}

/* Typography and Content */
h1, h2, h3, h4, h5, h6 {
  color: var(--sdi-primary-color);
  margin-bottom: 20px;
  font-weight: 600;
}

p {
  margin-bottom: 20px;
}

.sdi-post-summary {
  margin-bottom: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--sdi-border-color);
}

.sdi-post-summary:last-child {
  border-bottom: none;
}

.sdi-post-title {
  font-size: 2rem;
  margin-bottom: 15px;
}

.sdi-post-excerpt {
  margin-bottom: 20px;
  color: #555555;
}

.sdi-read-more {
  display: inline-block;
  background-color: var(--sdi-secondary-color);
  color: #ffffff;
  padding: 10px 20px;
  border-radius: 4px;
  font-weight: bold;
}

.sdi-read-more:hover {
  background-color: #128f76;
  text-decoration: none;
}

.sdi-post-heading {
  font-size: 2.5rem;
  margin-bottom: 30px;
  border-bottom: 2px solid var(--sdi-border-color);
  padding-bottom: 10px;
}

/* Sidebar Widgets */
.sdi-widget {
  background-color: #ffffff;
  padding: 25px;
  border-radius: 8px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  margin-bottom: 30px;
}

.sdi-widget-title {
  font-size: 1.2rem;
  border-bottom: 2px solid var(--sdi-secondary-color);
  padding-bottom: 10px;
  margin-bottom: 15px;
}

.sdi-widget-list {
  list-style: none;
}

.sdi-widget-item {
  margin-bottom: 10px;
  padding-bottom: 10px;
  border-bottom: 1px dashed var(--sdi-border-color);
}

.sdi-widget-item:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.sdi-widget-item a {
  color: var(--sdi-text-color);
}

.sdi-widget-item a:hover {
  color: var(--sdi-secondary-color);
}

/* Footer */
.sdi-footer {
  background-color: var(--sdi-primary-color);
  color: #ffffff;
  text-align: center;
  padding: 30px 20px;
  margin-top: 40px;
}

/* Pagination */
.sdi-pagination {
  display: flex;
  justify-content: space-between;
  margin-top: 30px;
}

/* Responsive */
@media (max-width: 768px) {
  .sdi-wrapper {
    flex-direction: column;
  }
  .sdi-main, .sdi-aside {
    flex: 1 1 100%;
  }
}