/* ============================================
   Dr. Faruk Arınç Portfolio - Design System
   ============================================ */

/* Google Fonts */
@import url("https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,500;0,600;0,700;1,400&family=Inter:wght@300;400;500;600;700&display=swap");

/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */
:root {
  /* Navy Color Scale */
  --navy-50: #f0f4f8;
  --navy-100: #d9e2ec;
  --navy-200: #bcccdc;
  --navy-300: #9fb3c8;
  --navy-400: #829ab1;
  --navy-500: #627d98;
  --navy-600: #486581;
  --navy-700: #334e68;
  --navy-800: #243b53;
  --navy-900: #102a43;
  --navy-950: #0a1929;

  /* Gold Accents */
  --gold-400: #f6ad55;
  --gold-500: #ed8936;
  --gold-600: #dd6b20;

  /* Typography */
  --font-display: "Playfair Display", Georgia, serif;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Container */
  --container-max: 1400px;
  --container-padding: 1.5rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15);

  /* Border Radius */
  --radius-sm: 0.125rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
}

/* ============================================
   Reset & Base Styles
   ============================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-display);
  background-color: var(--navy-950);
  color: var(--navy-100);
  line-height: 1.6;
  min-height: 100vh;
}

::selection {
  background-color: rgba(237, 137, 54, 0.3);
  color: white;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul,
ol {
  list-style: none;
}

/* ============================================
   Typography
   ============================================ */
.font-display {
  font-family: var(--font-display);
}
.font-body {
  font-family: var(--font-body);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-display);
  font-weight: 500;
  line-height: 1.2;
  color: white;
}

h1 {
  font-size: clamp(2.5rem, 8vw, 5rem);
}
h2 {
  font-size: clamp(2rem, 5vw, 3rem);
}
h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}
h4 {
  font-size: clamp(1.25rem, 2vw, 1.5rem);
}

p {
  font-family: var(--font-body);
  color: var(--navy-300);
  line-height: 1.7;
}

.text-sm {
  font-size: 0.875rem;
}
.text-xs {
  font-size: 0.75rem;
}
.text-lg {
  font-size: 1.125rem;
}
.text-xl {
  font-size: 1.25rem;
}

.text-gold {
  color: var(--gold-500);
}
.text-white {
  color: white;
}
.text-muted {
  color: var(--navy-400);
}

.uppercase {
  text-transform: uppercase;
  letter-spacing: 0.15em;
}

/* ============================================
   Layout
   ============================================ */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--space-4xl) 0;
}

.section--dark {
  background-color: var(--navy-900);
  border-top: 1px solid var(--navy-800);
}

.grid {
  display: grid;
  gap: var(--space-xl);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}
.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

@media (max-width: 768px) {
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Navigation
   ============================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background-color: rgba(10, 25, 41, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--navy-800);
}

.nav__container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  height: 5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav__logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: white;
  letter-spacing: -0.02em;
}

.nav__logo-dot {
  color: var(--gold-500);
  transition: color var(--transition-base);
}

.nav__logo:hover .nav__logo-dot {
  color: var(--gold-400);
}

.nav__menu {
  display: flex;
  gap: var(--space-xl);
}

.nav__link {
  font-family: var(--font-body);
  font-size: 0.7rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--navy-400);
  transition: color var(--transition-base);
  padding: var(--space-sm) 0;
  position: relative;
}

.nav__link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background-color: var(--gold-500);
  transition: width var(--transition-base);
}

.nav__link:hover,
.nav__link--active {
  color: var(--gold-400);
}

.nav__link:hover::after,
.nav__link--active::after {
  width: 100%;
}

/* Mobile Menu Toggle */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-sm);
  cursor: pointer;
}

.nav__toggle-bar {
  width: 24px;
  height: 2px;
  background-color: white;
  transition: all var(--transition-base);
}

@media (max-width: 768px) {
  .nav__toggle {
    display: flex;
  }

  .nav__menu {
    display: flex;
    position: fixed;
    top: 5rem;
    left: 0;
    right: 0;
    bottom: 0;
    height: calc(100vh - 5rem);
    width: 100%;
    z-index: 99;
    background-color: var(--navy-950);
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding-top: var(--space-3xl);
    gap: var(--space-lg);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: all var(--transition-base);
    overflow-y: auto;
  }

  .nav__menu--open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .nav__link {
    font-size: 1rem;
    padding: var(--space-sm) var(--space-md);
  }

  /* Hamburger Animation */
  .nav__toggle--active .nav__toggle-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .nav__toggle--active .nav__toggle-bar:nth-child(2) {
    opacity: 0;
  }

  .nav__toggle--active .nav__toggle-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 1rem 2rem;
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  cursor: pointer;
}

.btn--primary {
  background-color: var(--gold-500);
  color: var(--navy-950);
}

.btn--primary:hover {
  background-color: var(--gold-400);
  transform: translateY(-2px);
}

.btn--outline {
  background-color: transparent;
  color: var(--navy-300);
  border: 1px solid var(--navy-600);
}

.btn--outline:hover {
  border-color: var(--gold-500);
  color: var(--gold-500);
}

.btn--lg {
  padding: 1.25rem 2.5rem;
  font-size: 0.875rem;
}

/* ============================================
   Cards
   ============================================ */
.card {
  background-color: var(--navy-800);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--transition-base),
    box-shadow var(--transition-base);
  border: 1px solid var(--navy-700);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.card__image {
  aspect-ratio: 4/3;
  overflow: hidden;
}

.card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(100%);
  transition: all var(--transition-slow);
}

.card:hover .card__image img {
  filter: grayscale(0%);
  transform: scale(1.05);
}

.card__content {
  padding: var(--space-lg);
}

.card__title {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
  transition: color var(--transition-base);
}

.card:hover .card__title {
  color: var(--gold-400);
}

.card__subtitle {
  font-family: var(--font-body);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--navy-500);
}

/* ============================================
   Timeline
   ============================================ */
.timeline {
  position: relative;
  padding-left: var(--space-2xl);
}

.timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 1px;
  background-color: var(--navy-700);
}

.timeline__item {
  position: relative;
  padding-bottom: var(--space-2xl);
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__dot {
  position: absolute;
  left: calc(-1 * var(--space-2xl) - 4px);
  top: 0.5rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background-color: var(--navy-600);
}

.timeline__item--active .timeline__dot {
  background-color: var(--gold-500);
}

.timeline__year {
  font-family: var(--font-body);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gold-500);
  margin-bottom: var(--space-sm);
}

.timeline__item:not(.timeline__item--active) .timeline__year {
  color: var(--navy-600);
}

.timeline__title {
  font-size: 1.5rem;
  margin-bottom: var(--space-sm);
}

.timeline__description {
  font-size: 0.95rem;
  max-width: 600px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding-top: 10rem;
  padding-bottom: var(--space-4xl);
  min-height: 90vh;
  display: flex;
  align-items: center;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
  align-items: center;
}

@media (max-width: 768px) {
  .hero__grid {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

  .hero__image {
    order: -1;
  }
}

.hero__tag {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--gold-500);
  border-left: 2px solid var(--gold-500);
  padding-left: var(--space-md);
  margin-bottom: var(--space-xl);
}

.hero__title {
  font-size: clamp(3rem, 8vw, 6rem);
  font-weight: 500;
  line-height: 1.1;
  margin-bottom: var(--space-xl);
}

.hero__title-muted {
  color: var(--navy-500);
  font-style: italic;
}

.hero__description {
  font-size: 1.125rem;
  max-width: 500px;
  margin-bottom: var(--space-2xl);
}

.hero__buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.hero__image {
  position: relative;
  aspect-ratio: 3/4;
  overflow: hidden;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-xl);
  border: 1px solid rgba(237, 137, 54, 0.2);
}

.hero__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 1s ease;
}

.hero__image:hover img {
  transform: scale(1.05);
}

.hero__image-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(10, 25, 41, 0.4), transparent);
}

/* ============================================
   Gallery & Lightbox
   ============================================ */
.gallery {
  columns: 3;
  column-gap: var(--space-lg);
}

@media (max-width: 1024px) {
  .gallery {
    columns: 2;
  }
}

@media (max-width: 640px) {
  .gallery {
    columns: 1;
  }
}

.gallery__item {
  break-inside: avoid;
  margin-bottom: var(--space-lg);
  cursor: pointer;
  overflow: hidden;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  border: 1px solid rgba(237, 137, 54, 0.1);
}

.gallery__item img {
  transition: all var(--transition-base);
}

.gallery__item:hover img {
  transform: scale(1.03);
  opacity: 0.85;
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background-color: rgba(10, 25, 41, 0.98);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
}

.lightbox--open {
  opacity: 1;
  visibility: visible;
}

.lightbox__content {
  max-width: 90vw;
  max-height: 90vh;
}

.lightbox__content img {
  max-width: 100%;
  max-height: 90vh;
  object-fit: contain;
}

.lightbox__close {
  position: absolute;
  top: var(--space-lg);
  right: var(--space-lg);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 2rem;
  cursor: pointer;
  transition: color var(--transition-base);
}

.lightbox__close:hover {
  color: var(--gold-500);
}

.lightbox__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 2rem;
  cursor: pointer;
  transition: color var(--transition-base);
}

.lightbox__nav:hover {
  color: var(--gold-500);
}

.lightbox__nav--prev {
  left: var(--space-lg);
}
.lightbox__nav--next {
  right: var(--space-lg);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  padding: var(--space-4xl) 0;
  border-top: 1px solid var(--navy-800);
  text-align: center;
}

.footer__name {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-xl);
}

.footer__links {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.footer__link {
  font-family: var(--font-body);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--navy-500);
  transition: color var(--transition-base);
}

.footer__link:hover {
  color: var(--gold-400);
}

.footer__copyright {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--navy-600);
}

/* ============================================
   Page Header (for inner pages)
   ============================================ */
.page-header {
  padding-top: 10rem;
  padding-bottom: var(--space-3xl);
  text-align: center;
}

.page-header__tag {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--gold-500);
  margin-bottom: var(--space-lg);
}

.page-header__title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  margin-bottom: var(--space-lg);
}

.page-header__description {
  font-size: 1.125rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   Animations
   ============================================ */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in--visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   Utilities
   ============================================ */
.mb-0 {
  margin-bottom: 0;
}
.mb-sm {
  margin-bottom: var(--space-sm);
}
.mb-md {
  margin-bottom: var(--space-md);
}
.mb-lg {
  margin-bottom: var(--space-lg);
}
.mb-xl {
  margin-bottom: var(--space-xl);
}
.mb-2xl {
  margin-bottom: var(--space-2xl);
}
.mb-3xl {
  margin-bottom: var(--space-3xl);
}

.mt-0 {
  margin-top: 0;
}
.mt-lg {
  margin-top: var(--space-lg);
}
.mt-xl {
  margin-top: var(--space-xl);
}

.text-center {
  text-align: center;
}
.text-left {
  text-align: left;
}
.text-right {
  text-align: right;
}

.flex {
  display: flex;
}
.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}
.flex-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.flex-wrap {
  flex-wrap: wrap;
}
.gap-sm {
  gap: var(--space-sm);
}
.gap-md {
  gap: var(--space-md);
}
.gap-lg {
  gap: var(--space-lg);
}
.gap-xl {
  gap: var(--space-xl);
}

/* ============================================
   Publication / List Items
   ============================================ */
.pub-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.pub-item {
  padding: var(--space-lg);
  background-color: var(--navy-800);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--gold-500);
  transition: transform var(--transition-base);
}

.pub-item:hover {
  transform: translateX(4px);
}

.pub-item__title {
  font-size: 1.125rem;
  margin-bottom: var(--space-sm);
}

.pub-item__meta {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--navy-400);
}

/* ============================================
   Course/Teaching Cards
   ============================================ */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.course-card {
  background-color: var(--navy-800);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
  border: 1px solid var(--navy-700);
  transition: all var(--transition-base);
}

.course-card:hover {
  border-color: var(--gold-500);
  transform: translateY(-2px);
}

.course-card__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--navy-700);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
  color: var(--gold-500);
}

.course-card__title {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

.course-card__description {
  font-size: 0.9rem;
  margin-bottom: var(--space-lg);
}

.course-card__link {
  font-family: var(--font-body);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--gold-500);
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  transition: gap var(--transition-base);
}

.course-card:hover .course-card__link {
  gap: var(--space-sm);
}

/* ============================================
   Contact Form (Visual Only)
   ============================================ */
.contact-form {
  max-width: 500px;
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-label {
  display: block;
  font-family: var(--font-body);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--navy-400);
  margin-bottom: var(--space-sm);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  background-color: var(--navy-800);
  border: 1px solid var(--navy-700);
  border-radius: var(--radius-md);
  color: white;
  font-family: var(--font-body);
  font-size: 1rem;
  transition: border-color var(--transition-base);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--gold-500);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

/* ============================================
   Contact Info Grid
   ============================================ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-xl);
}

.contact-item {
  text-align: center;
  padding: var(--space-xl);
}

.contact-item__icon {
  width: 64px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--navy-800);
  border-radius: 50%;
  margin: 0 auto var(--space-lg);
  color: var(--gold-500);
  border: 1px solid var(--navy-700);
}

.contact-item__label {
  font-family: var(--font-body);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--navy-500);
  margin-bottom: var(--space-sm);
}

.contact-item__value {
  font-size: 1rem;
  color: white;
}

.contact-item__value a {
  color: var(--gold-500);
  transition: color var(--transition-base);
}

.contact-item__value a:hover {
  color: var(--gold-400);
}

/* ============================================
   External Links Section
   ============================================ */
.links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-lg);
}

.link-card {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg);
  background-color: var(--navy-800);
  border-radius: var(--radius-md);
  border: 1px solid var(--navy-700);
  transition: all var(--transition-base);
}

.link-card:hover {
  border-color: var(--gold-500);
  transform: translateY(-2px);
}

.link-card__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--navy-700);
  border-radius: var(--radius-md);
  color: var(--gold-500);
  flex-shrink: 0;
}

.link-card__content {
  flex: 1;
}

.link-card__title {
  font-size: 1rem;
  margin-bottom: var(--space-xs);
}

.link-card__description {
  font-size: 0.8rem;
  color: var(--navy-400);
}