:root {
  --bg: #0b1220;
  --panel: #ffffff;
  --panel-alt: #f4f7fb;
  --text: #1c2430;
  --muted: #4a5565;
  --line: #dfe7f1;
  --accent: #1d4ed8;
  --accent-dark: #153ea8;
  --shadow: rgba(15, 23, 42, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: linear-gradient(180deg, #0b1220 0%, #111827 100%);
  color: var(--text);
  overflow-x: hidden;
}

img,
video,
audio,
object {
  max-width: 100%;
}

.page-shell {
  width: calc(100% - 2rem);
  max-width: 1100px;
  margin: 2rem auto;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 20px;
  box-shadow: 0 18px 40px var(--shadow);
  overflow: hidden;
}

.site-header {
  background: linear-gradient(135deg, #1d4ed8, #dbeafe 100%);
  padding: 2rem 1.5rem;
}

.site-header h1 {
  margin: 0;
  font-size: clamp(1.8rem, 2.5vw, 2.6rem);
  color: #0f172a;
  text-align: center;
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.content {
  padding: 2rem 1.5rem 3rem;
}

.content section + section {
  margin-top: 2.5rem;
}

.content h2 {
  margin-bottom: 1rem;
  font-size: clamp(1.3rem, 2vw, 1.8rem);
  color: #111827;
  text-align: center;
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.content h3 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
  color: #111827;
}

.content p,
.content li {
  line-height: 1.7;
  color: var(--text);
}

.intro,
.audio-section,
.video-section,
.project-showcase,
.pdf-section,
.download-section {
  background: var(--panel-alt);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 1.5rem;
}

.media-list {
  display: grid;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.media-item {
  padding: 1rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.media-item audio,
.video-section video,
.pdf-viewer {
  width: 100%;
  border-radius: 10px;
}

.image-card {
  margin: 1.25rem auto;
  text-align: center;
}

.image-card img {
  display: block;
  width: min(100%, 850px);
  margin: 0 auto;
  border-radius: 12px;
  border: 1px solid var(--line);
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
}

.app-preview img {
  max-width: 320px;
}

.project-showcase a,
.pdf-section a {
  color: var(--accent);
  text-decoration: underline;
}

.project-showcase a:hover,
.pdf-section a:hover,
.project-showcase a:focus-visible,
.pdf-section a:focus-visible {
  color: var(--accent-dark);
}

.pdf-viewer {
  min-height: 900px;
  border: 1px solid #000;
  background: #fff;
}

.download-button {
  display: inline-block;
  padding: 0.9rem 1.5rem;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  transition: background 0.2s ease, transform 0.2s ease;
}

.download-section {
  text-align: center;
}

.download-button:hover,
.download-button:focus-visible {
  background: var(--accent-dark);
  transform: translateY(-1px);
}

.site-footer {
  background: #111827;
  color: #e5edf8;
}

.footer-container {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2rem;
  padding: 2rem 1.5rem;
}

.footer-column h3 {
  margin: 0 0 0.75rem;
  color: #fff;
  font-size: 1rem;
}

.footer-column p,
.footer-column li {
  margin: 0 0 0.5rem;
  color: #c7d2e2;
  line-height: 1.5;
}

.footer-column ul {
  margin: 0;
  padding-left: 1.2rem;
}

.footer-column a {
  color: #bfdbfe;
  text-decoration: underline;
  text-underline-offset: 0.15em;
}

.footer-column a:hover,
.footer-column a:focus-visible {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid rgba(229, 237, 248, 0.2);
  padding: 1rem 1.5rem;
  text-align: center;
}

.footer-bottom p {
  margin: 0;
  color: #aebdd1;
  font-size: 0.9rem;
}

@media (max-width: 640px) {
  .page-shell {
    width: calc(100% - 1rem);
    max-width: 1100px;
    margin: 1rem auto;
  }

  .site-header,
  .content {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .intro,
  .audio-section,
  .video-section,
  .project-showcase,
  .pdf-section,
  .download-section {
    padding: 1rem;
  }

  .pdf-viewer {
    min-height: 640px;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding: 1.5rem 1rem;
  }

  .footer-bottom {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}