:root {
  --color-bg: #ffffff;
  --color-text: #111827;
  --color-primary: #2563eb;
  --color-muted: #374151;
  --color-border: #d1d5db;
  --max-width: 48rem;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  font-size: 1.0625rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  border-bottom: 1px solid var(--color-border);
}

nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-text);
  text-decoration: none;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 1.5rem;
}

nav a {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
}

nav a:hover,
nav a:focus {
  text-decoration: underline;
}

main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  width: 100%;
}

section {
  margin-bottom: 3rem;
}

h1, h2, h3, h4 {
  line-height: 1.2;
  margin-bottom: 1rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

h1 {
  font-size: 2.75rem;
}

h2 {
  font-size: 2rem;
  margin-top: 2.5rem;
}

h3 {
  font-size: 1.5rem;
  margin-top: 1.5rem;
}

p {
  margin-bottom: 1.25rem;
  color: var(--color-muted);
}

.hero {
  text-align: center;
}

.title-line {
  font-size: 1.125rem;
  color: var(--color-muted);
  margin-bottom: 1rem;
}

.mission {
  font-size: 1.125rem;
  color: var(--color-text);
  max-width: 40rem;
  margin: 0 auto 1.5rem;
}

.cta-group {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  margin-top: 1.5rem;
}

.btn,
button.btn {
  display: inline-block;
  padding: 0.75rem 1.25rem;
  border: 1px solid var(--color-text);
  border-radius: 0.375rem;
  color: var(--color-text);
  text-decoration: none;
  font: inherit;
  font-weight: 500;
  line-height: 1.2;
  text-align: center;
  box-sizing: border-box;
  transition: background 0.2s, color 0.2s;
}

.btn:hover,
.btn:focus {
  background: var(--color-text);
  color: var(--color-bg);
}

code {
  background: #f3f4f6;
  color: var(--color-text);
  padding: 0.125rem 0.25rem;
  border-radius: 0.25rem;
  font-family: ui-monospace, SFMono-Regular, Consolas, 'Liberation Mono', Menlo, monospace;
}

pre {
  background: #f3f4f6;
  color: var(--color-text);
  padding: 1rem;
  border-radius: 0.5rem;
  overflow-x: auto;
  margin-bottom: 1rem;
}

pre code {
  background: transparent;
  padding: 0;
}

article,
.topic-content {
  font-size: 1.125rem;
  line-height: 1.8;
}

.cards {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}

.admin-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.admin-card {
  display: block;
  padding: 1.5rem;
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  text-decoration: none;
  color: var(--color-text);
  background: var(--color-bg);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.admin-card:hover,
.admin-card:focus {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.admin-card h2 {
  margin: 0 0 0.5rem;
  font-size: 1.25rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.35rem 0.7rem;
  border: 1px solid var(--color-border);
  border-radius: 9999px;
  font-size: 0.9rem;
  background: var(--color-bg);
  color: var(--color-text);
  text-decoration: none;
}

.tag-chip.selected {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.skills ul,
.about ul {
  list-style: disc;
  padding-left: 1.5rem;
}

.topic-content ul,
.topic-content ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.topic-content ul {
  list-style: disc;
}

.topic-content ol {
  list-style: decimal;
}

.topic-content ul ul,
.topic-content ol ol,
.topic-content ul ol,
.topic-content ol ul {
  margin-top: 0.25rem;
  margin-bottom: 0.25rem;
}

.topic-content li {
  margin-bottom: 0.5rem;
}

.project-card {
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.project-card h3 {
  margin-bottom: 0.5rem;
}

.contact-list {
  list-style: none;
  margin-top: 1rem;
}

.contact-list li {
  margin-bottom: 0.75rem;
}

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

.contact-list a:hover,
.contact-list a:focus {
  text-decoration: underline;
}

footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem;
  text-align: center;
}

footer nav {
  display: block;
  margin-bottom: 1rem;
}

footer ul {
  display: flex;
  justify-content: center;
  list-style: none;
  gap: 1.5rem;
  margin-bottom: 0.5rem;
}

@media (max-width: 640px) {
  h1 {
    font-size: 2rem;
  }

  nav {
    flex-direction: column;
    gap: 1rem;
  }

  .mission {
    font-size: 1rem;
  }

  .btn {
    width: 100%;
  }
}

.enquiry-form {
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  padding: 1.5rem;
  margin-top: 1.5rem;
}

input:not([type="checkbox"]):not([type="radio"]):not([type="submit"]):not([type="button"]),
select,
textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 0.375rem;
  font-size: 1rem;
  font-family: inherit;
  background: var(--color-bg);
  color: var(--color-text);
  box-sizing: border-box;
}

input:not([type="checkbox"]):not([type="radio"]):not([type="submit"]):not([type="button"]):focus,
select:focus,
textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

textarea {
  min-height: 6rem;
  resize: vertical;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--color-text);
}

button.btn {
  background: var(--color-text);
  color: var(--color-bg);
  cursor: pointer;
}

button.btn:hover,
button.btn:focus {
  background: var(--color-muted);
}