:root {
  --color-primary: #003999;
  --color-primary-hover: #003388;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-background: #f8fafc;
  --color-surface: #fff;
  --color-surface-hover: #f1f5f9;

  --font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.5rem;
  --font-size-xl: 2.5rem;
  --line-height-base: 1.6;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-3xl: 4rem;

  --border-radius: 0.125rem;
  --border-width: 0.0625rem;

  --shadow-lg: 0 0.625 1rem rgba(0, 0, 0, 0.1);

  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;

  --container-max-width: 75rem;
  --container-padding: var(--space-md);
}

[data-theme="dark"] {
  --color-text: #e2e8f0;
  --color-text-muted: #8b9ab8;
  --color-border: #2d3a4d;
  --color-background: #10151d;
  --color-surface: #171f2b;
  --color-surface-hover: #212b38;

  --shadow-lg: 0 0.625 1rem rgba(0, 0, 0, 0.5);
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-background);
  transition: background-color var(--transition-base), color var(--transition-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-background);
  border-bottom: var(--border-width) solid var(--color-border);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

main > section {
  scroll-margin-top: 5rem;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 4.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  text-decoration: none;
}

.logo h1 {
  font-family: "Dynalight", cursive;
  font-size: 2.5rem;
  font-weight: normal;
  color: var(--color-text);
  margin: 0;
  line-height: 1;
}

.logo img {
  border: 0.0625rem solid var(--color-text-muted);
  border-radius: 50%;
  box-shadow: var(--shadow-lg);
  height: 3rem;
  object-fit: cover;
  width: 3rem;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.lang-toggle,
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  background-color: transparent;
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.lang-toggle:hover,
.theme-toggle:hover {
  background-color: var(--color-surface-hover);
  border-color: var(--color-primary);
}

.lang-toggle:focus-visible,
.theme-toggle:focus-visible {
  outline: 0.125rem solid var(--color-primary);
  outline-offset: 0.125rem;
}

.lang-toggle .lang-en,
.lang-toggle .lang-tr,
[data-lang="en"] .lang-tr,
[data-lang="tr"] .lang-en {
  display: none;
}

[data-lang="en"] .lang-en,
[data-lang="tr"] .lang-tr {
  display: inline;
}

.theme-toggle .icon-moon {
  display: none;
}

[data-theme="dark"] .icon-sun {
  display: none;
}

[data-theme="dark"] .icon-moon {
  display: block;
}

.about-hero {
  padding: var(--space-3xl) 0;
  border-bottom: var(--border-width) solid var(--color-border);
}

.about-hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: center;
}

.about-hero-content {
  order: 1;
  display: flex;
  flex-direction: column;
  gap: 1.925rem;
}

.about-titles {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  list-style: none;
}

.about-titles li {
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  background-color: var(--color-surface);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
  line-height: 1.5rem;
}

.about-titles li:nth-child(1) {
  font-size: 1rem;
}

.about-titles li:nth-child(2) {
  font-size: 0.92rem;
  opacity: 0.9;
}

.about-titles li:nth-child(3) {
  font-size: 0.84rem;
  opacity: 0.8;
}

.about-titles li:nth-child(4) {
  font-size: 0.76rem;
  opacity: 0.7;
}

.about-titles li:nth-child(5) {
  font-size: 0.68rem;
  opacity: 0.6;
}

.about-description {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  line-height: var(--line-height-base);
}

.about-links {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.about-hero-visual {
  display: flex;
  justify-content: center;
  order: 2;
}

.about-hero-visual img {
  width: 100%;
  max-width: 20rem;
  height: auto;
  border-radius: var(--border-radius);
  object-fit: cover;
  box-shadow: var(--shadow-lg);
}

.projects {
  padding: var(--space-3xl) 0;
}

.section-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--space-xl);
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.project-card {
  display: flex;
  flex-direction: column;
  padding: var(--space-lg);
  background-color: var(--color-surface);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-base), border-color var(--transition-base);
}

.project-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-lg);
}

.project-header {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.project-badge {
  display: inline-block;
  width: fit-content;
  padding: var(--space-xs) var(--space-sm);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  background-color: var(--color-background);
  border-radius: var(--border-radius);
}

.project-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
}

.project-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  flex-grow: 1;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  list-style: none;
  margin-bottom: var(--space-lg);
}

.project-tech li {
  padding: var(--space-xs) var(--space-sm);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  background-color: var(--color-background);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
}

.project-links {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.btn-icon::after {
  display: none !important;
}

.btn-primary::after {
  content: "";
  display: inline-block;
  width: 0.875rem;
  height: 0.875rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23ffffff' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  background-size: contain;
  background-repeat: no-repeat;
}

.btn-secondary {
  color: var(--color-text);
  background-color: transparent;
  border: var(--border-width) solid var(--color-border);
}

.btn-secondary::after {
  content: "";
  display: inline-block;
  width: 0.875rem;
  height: 0.875rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%231e293b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  background-size: contain;
  background-repeat: no-repeat;
}

[data-theme="dark"] .btn-secondary::after {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23e2e8f0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
}

.btn:focus-visible {
  outline: 0.125rem solid var(--color-primary);
  outline-offset: 0.125rem;
}

.btn-primary {
  color: #ffffff;
  background-color: var(--color-primary);
  border: var(--border-width) solid var(--color-primary);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
}

.btn-secondary:hover {
  background-color: var(--color-surface-hover);
  border-color: var(--color-primary);
}

.contact {
  padding: var(--space-3xl) 0;
  text-align: center;
  border-top: var(--border-width) solid var(--color-border);
}

.contact-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--space-sm);
}

.contact-text {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.contact-link {
  aspect-ratio: 1 / 1;
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  text-decoration: none;
  background-color: var(--color-surface);
  border: var(--border-width) solid var(--color-border);
  border-radius: var(--border-radius);
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.contact-link:hover {
  background-color: var(--color-surface-hover);
  border-color: var(--color-text);
  color: var(--color-text);
}

.contact-link:focus-visible {
  outline: 0.125rem solid var(--color-primary);
  outline-offset: 0.125rem;
}

.contact-link svg {
  height: 1.25rem;
  width: 1.25rem;
}

.footer {
  padding: var(--space-lg) 0;
  text-align: center;
  border-top: var(--border-width) solid var(--color-border);
}

.footer p {
  color: var(--color-text-muted);
  font-family: monospace;
  font-size: var(--font-size-xs);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (max-width: 48rem) {

  .about-hero,
  .projects,
  .contact {
      padding: var(--space-xl) 0;
  }

  .about-hero .container {
    grid-template-columns: 1fr;
  }

  .about-hero-content {
    order: 2;
  }

  .about-hero-visual {
    order: 1;
  }

  .about-hero-content {
      gap: 1.125rem;
  }

  .about-titles li {
      line-height: 1rem;
  }

  .project-grid {
    grid-template-columns: repeat(1, 1fr);
  }
}