/* Variables for Light Theme */
:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --link: #0000ee;
  --link-hover: #000099;
  --border: #dddddd;
  --meta: #666666;
  --bg-secondary: #f9f9f9;
}


/* Base Styles */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  font-family: "SamsungOne", Roboto, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--text);
  background-color: var(--bg);
  line-height: 1.6;
  margin: 0;
  padding: 0;
  font-size: 18px;
}

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

/* Header & Nav */
header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-container {
  max-width: 680px;
  margin: 0 auto;
  padding: 1rem 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  font-weight: bold;
  font-size: 1.2rem;
}

.desktop-nav a {
  margin-left: 15px;
  font-size: 0.95rem;
  color: var(--text);
}
.desktop-nav a:hover {
  text-decoration: underline;
}

/* Mobile Nav Native Details Element */
.mobile-menu {
  display: none;
  position: relative;
}
.mobile-menu summary {
  list-style: none;
  cursor: pointer;
  font-weight: bold;
  user-select: none;
}
.mobile-menu summary::-webkit-details-marker {
  display: none;
}
.mobile-nav {
  position: absolute;
  top: 100%;
  right: 0;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  padding: 10px;
  display: flex;
  flex-direction: column;
  min-width: 150px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  margin-top: 10px;
  border-radius: 4px;
}
.mobile-nav a {
  padding: 8px 10px;
  color: var(--text);
  display: block;
}
.mobile-nav a:hover {
  background-color: var(--border);
}

@media (max-width: 600px) {
  .desktop-nav {
    display: none;
  }
  .mobile-menu {
    display: block;
  }
}

/* Main Container */
main {
  max-width: 680px;
  margin: 0 auto;
  padding: 2rem 20px 4rem 20px;
}

section {
  padding-top: 1rem;
  margin-bottom: 3rem;
}

h1, h2, h3 {
  line-height: 1.2;
}

h1 {
  font-size: 2.2rem;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.6rem;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0.3rem;
  margin-bottom: 1.5rem;
}

.subtitle {
  font-size: 1.1rem;
  color: var(--meta);
  margin-top: 0;
}

/* Experience Timeline */
.timeline {
  list-style-type: none;
  padding: 0;
  margin: 0;
  position: relative;
}
.timeline::before {
  content: "";
  position: absolute;
  top: 6px;
  bottom: 0;
  left: 6px; /* Centers exactly on the 14px dot */
  width: 2px;
  background-color: var(--border);
}
.timeline li {
  margin-bottom: 25px;
  position: relative;
  padding-left: 28px;
}
.timeline li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background-color: var(--bg);
  border: 2px solid var(--border);
  z-index: 1;
}
.timeline-date {
  font-size: 0.85rem;
  color: var(--meta);
  font-weight: bold;
}
.timeline-content h3 {
  margin: 0.2rem 0;
  font-size: 1.1rem;
}
.timeline-content p {
  margin: 0.2rem 0 0 0;
  font-size: 0.95rem;
}

/* Projects Grid/List */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 15px;
}
@media (min-width: 601px) {
  .projects-grid {
    grid-template-columns: 1fr 1fr;
  }
}
.project-card {
  border: 1px solid var(--border);
  padding: 15px;
  border-radius: 6px;
  background-color: var(--bg-secondary);
}
.project-card h3 {
  margin: 0 0 5px 0;
  font-size: 1.1rem;
}
.project-desc {
  margin: 0 0 10px 0;
  font-size: 0.95rem;
}
.project-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.tag {
  font-size: 0.75rem;
  background-color: var(--border);
  padding: 2px 6px;
  border-radius: 3px;
  color: var(--text);
}

/* Blog List */
.rss-note {
  font-size: 0.9rem;
  color: var(--meta);
  margin-bottom: 1rem;
  font-style: italic;
}
.blog-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.blog-list li {
  display: flex;
  align-items: baseline;
  margin-bottom: 12px;
}
.post-date {
  font-size: 0.9rem;
  color: var(--meta);
  min-width: 110px;
  font-family: monospace;
}
.post-link {
  font-size: 1.05rem;
  flex-grow: 1;
}

/* Contact / Footer */
@media (max-width: 600px) {
  .blog-list li {
    flex-direction: column;
    margin-bottom: 20px;
  }
  .post-date {
    font-size: 0.8rem;
    margin-bottom: 5px;
  }
}

.contact-links {
  list-style: none;
  padding: 0;
  display: flex;
  gap: 15px;
}
footer {
  text-align: center;
  padding: 2rem 20px;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--meta);
}