@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700;800&display=swap');

:root {
  /* Font */
  --font-family: 'Inter', sans-serif;

  /* Renkler */
  --color-bg: #f5f7fa;
  --color-text: #222;
  --color-primary: #0a66c2;
  --color-primary-dark: #084a91;
  --color-navbar-bg: #1e272e;
  --color-navbar-text: #eee;
  --color-section-bg: #fff;
  --color-section-border: #0a66c2;
  --color-section-shadow: rgba(0, 0, 0, 0.07);
  --color-section-shadow-hover: rgba(10, 102, 194, 0.25);
  --color-skill-bg: #0a66c2;
  --color-skill-bg-hover: #084a91;
  --color-footer-bg: #1e272e;
  --color-footer-text: #bbb;
  --color-link: #0a66c2;

  /* Gölge ve efektler */
  --text-shadow-dark: rgba(0, 0, 0, 0.6);
  --text-shadow-light: rgba(0, 0, 0, 0.5);
  --btn-shadow: rgba(10, 102, 194, 0.4);
  --btn-shadow-hover: rgba(8, 74, 145, 0.6);
  --nav-shadow: rgba(0, 0, 0, 0.1);

  /* Border radius */
  --border-radius-btn: 50px;
  --border-radius-section-ul-li: 12px;
  --border-radius-skill-tag: 30px;

  /* Font boyutları */
  --font-size-base: 16px;
  --font-size-hero-h1: 3rem;
  --font-size-hero-p: 1.3rem;
  --font-size-section-h2: 2rem;
  --font-size-skill-tag: 0.9rem;
  --font-size-footer: 0.9rem;
  --font-size-hero-h1-mobile: 2.2rem;
  --font-size-hero-p-mobile: 1.1rem;
  --font-size-section-h2-mobile: 1.6rem;

  /* Padding */
  --padding-hero: 120px 240px;
  --padding-hero-mobile: 90px 15px 80px;
  --btn-padding: 12px 28px;
  --nav-padding-y: 15px;
  --section-ul-li-padding: 20px 25px;
  --section-ul-li-padding-mobile: 18px 20px;
  --footer-padding: 25px 20px;

  /* Margin */
  --margin-section: 60px auto;
  --margin-section-mobile: 40px 15px;
  --section-ul-li-margin-bottom: 18px;
  --footer-margin-top: 70px;

  /* Diğer */
  --section-max-width: 900px;
  --transition-duration: 0.3s;
  --transition-fast: 0.2s;
  --transition-slow: 0.4s;
  --z-index-navbar: 999;

  /* Arkaplanlar */
  --hero-gradient: linear-gradient(135deg, #0a66c2cc 0%, #1e272ecc 100%);
  --hero-image: url('https://images.unsplash.com/photo-1522071820081-009f0129c71c?auto=format&fit=crop&w=1350&q=80');

  /* Animasyonlar */
  --animation-fade-duration: 0.7s;
  --animation-delay-step: 0.2s;
}

/* Genel Ayarlar */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: var(--font-family);
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: 0.02em;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

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

a:hover {
  text-decoration: underline;
}

/* Navbar */
nav {
  background: var(--color-navbar-bg);
  position: sticky;
  top: 0;
  z-index: var(--z-index-navbar);
  box-shadow: 0 2px 5px var(--nav-shadow);
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
}

nav ul li {
  margin: 0 15px;
}

nav ul li a {
  color: var(--color-navbar-text);
  font-weight: 600;
  padding: var(--nav-padding-y) 0;
  display: block;
  transition: color var(--transition-duration) ease, border-bottom var(--transition-duration) ease;
  border-bottom: 3px solid transparent;
}

nav ul li a.active,
nav ul li a:hover {
  color: var(--color-primary);
  border-bottom: 3px solid var(--color-primary);
}

/* Hero Alanı */
header#hero {
  position: relative;
  background-image: var(--hero-gradient), var(--hero-image);
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
  color: #fff;
  text-align: center;
  padding: var(--padding-hero);
  overflow: hidden;
}

header#hero h1 {
  font-size: var(--font-size-hero-h1);
  margin-bottom: 10px;
  font-weight: 800;
  text-shadow: 1px 1px 4px var(--text-shadow-dark);
}

header#hero p {
  font-size: var(--font-size-hero-p);
  margin-bottom: 25px;
  font-weight: 500;
  text-shadow: 0 1px 4px var(--text-shadow-light);
}

header#hero .btn {
  background: var(--color-primary);
  color: #fff;
  padding: var(--btn-padding);
  border-radius: var(--border-radius-btn);
  box-shadow: 0 4px 8px var(--btn-shadow);
  transition: background var(--transition-duration) ease, transform var(--transition-fast) ease;
  display: inline-block;
  margin: 0 10px;
  font-weight: 600;
}

header#hero .btn:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 6px 12px var(--btn-shadow-hover);
  transform: translateY(-3px);
}

/* Bölümler */
section {
  max-width: var(--section-max-width);
  margin: var(--margin-section);
  padding: 0 20px;
}

section h2 {
  font-size: var(--font-size-section-h2);
  color: var(--color-primary);
  border-bottom: 3px solid var(--color-section-border);
  padding-bottom: 6px;
  margin-bottom: 30px;
  font-weight: 700;
}

section ul {
  list-style: none;
}

section ul li {
  background: var(--color-section-bg);
  padding: var(--section-ul-li-padding);
  margin-bottom: var(--section-ul-li-margin-bottom);
  border-radius: var(--border-radius-section-ul-li);
  box-shadow: 0 3px 8px var(--color-section-shadow);
  border-left: 5px solid var(--color-section-border);
  transition: transform var(--transition-fast) ease, box-shadow var(--transition-fast) ease;
}

section ul li:hover {
  transform: translateX(5px);
  box-shadow: 0 6px 15px var(--color-section-shadow-hover);
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

.skill-tag {
  background: var(--color-skill-bg);
  color: #fff;
  padding: 8px 18px;
  border-radius: var(--border-radius-skill-tag);
  font-weight: 600;
  font-size: var(--font-size-skill-tag);
  box-shadow: 0 2px 6px var(--btn-shadow);
  transition: background var(--transition-duration) ease, transform var(--transition-fast) ease;
}

.skill-tag:hover {
  background: var(--color-skill-bg-hover);
  transform: scale(1.05);
}

#iletisim a {
  color: var(--color-link);
  font-weight: 600;
}

.download-btn:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 6px 12px var(--btn-shadow-hover);
  transform: scale(1.05);
}

.download-btn {
  margin-top: 20px;
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
  padding: var(--btn-padding);
  border-radius: var(--border-radius-btn);
  box-shadow: 0 4px 8px var(--btn-shadow);
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  transition: background var(--transition-duration) ease, box-shadow var(--transition-duration) ease, transform var(--transition-fast) ease;
}

footer {
  text-align: center;
  padding: var(--footer-padding);
  background: var(--color-footer-bg);
  color: var(--color-footer-text);
  font-size: var(--font-size-footer);
  margin-top: var(--footer-margin-top);
}

.return-btn:hover {
  background: var(--color-primary);
  transform: scale(1.05);
}

.return-btn {
  display: inline-block;
  margin-bottom: 20px;
  background: var(--color-navbar-bg);
  color: #fff;
  font-weight: 600;
  padding: 10px 24px;
  border-radius: var(--border-radius-btn);
  box-shadow: 0 3px 10px var(--text-shadow-dark);
  text-decoration: none;
  transition: background var(--transition-duration) ease, transform var(--transition-fast) ease;
}

iframe {
  width: 100%;
  height: 90vh;
  border-radius: var(--border-radius-section-ul-li);
  box-shadow: 0 6px 20px var(--btn-shadow);
  border: none;
  animation: fadeInScale var(--animation-fade-duration) ease forwards;
  opacity: 0;
  transform: scale(0.95);
}

/* Animasyon */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  animation: fadeInUp var(--animation-fade-duration) ease forwards;
}

@keyframes fadeInScale {
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.fade-in:nth-child(2) {
  animation-delay: calc(var(--animation-delay-step) * 1);
}

.fade-in:nth-child(3) {
  animation-delay: calc(var(--animation-delay-step) * 2);
}

.fade-in:nth-child(4) {
  animation-delay: calc(var(--animation-delay-step) * 3);
}

.fade-in:nth-child(5) {
  animation-delay: calc(var(--animation-delay-step) * 4);
}

.fade-in:nth-child(6) {
  animation-delay: calc(var(--animation-delay-step) * 5);
}

.fade-in:nth-child(7) {
  animation-delay: calc(var(--animation-delay-step) * 6);
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive */
@media (max-width: 768px) {
  header#hero {
    padding: var(--padding-hero-mobile);
  }

  header#hero h1 {
    font-size: var(--font-size-hero-h1-mobile);
  }

  header#hero p {
    font-size: var(--font-size-hero-p-mobile);
  }

  nav ul {
    flex-wrap: wrap;
  }

  nav ul li {
    margin: 8px 10px;
  }

  section {
    margin: var(--margin-section-mobile);
  }

  section h2 {
    font-size: var(--font-size-section-h2-mobile);
    margin-bottom: 20px;
  }

  iframe {
    width: 100%;
    height: 90vh;
  }
}

@media (max-width: 480px) {
  .skills-list {
    justify-content: center;
  }

  section ul li {
    padding: var(--section-ul-li-padding-mobile);
  }
}

/* Hamburger Menü Stili */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 2rem;
  color: var(--color-primary, #333);
  cursor: pointer;
  position: absolute;
  right: 24px;
  top: 18px;
  z-index: 1100;
}

nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

@media (max-width: 800px) {
  .menu-toggle {
    display: block;
  }
  nav ul {
    flex-direction: column;
    position: absolute;
    top: 60px;
    right: 0;
    background: #181a40;
    width: 200px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    z-index: 1000;
    align-items: flex-start;
    padding: 1rem 0;
    border-radius: 0 0 0 12px;
  }
  nav ul.open {
    transform: translateX(0);
  }
  nav ul li {
    width: 100%;
    margin: 0;
    padding: 0.5rem 1.5rem;
  }
  nav ul li a {
    width: 100%;
    display: block;
    padding: 0.5rem 0;
  }
}