/* ==================== CSS VARIABLES ==================== */
:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f6f7fb;
  --text-primary: #17171f;
  --text-secondary: #5c5f6a;
  --accent: #4338ca;
  --accent-hover: #362f9e;
  --accent-soft: rgba(67, 56, 202, 0.1);
  --border-color: #e2e2ea;
  --nav-bg: #14142b;
  --nav-text: #f4f4f8;
  --nav-text-muted: #a6a8c2;
  --shadow: 0 4px 6px rgba(17, 17, 32, 0.08);
  --shadow-lg: 0 16px 32px rgba(17, 17, 32, 0.12);
  --shadow-nav: 0 2px 16px rgba(0, 0, 0, 0.2);
  --transition: all 0.25s ease;
  --nav-height: 76px;
}

body.dark-mode {
  --bg-primary: #121218;
  --bg-secondary: #1c1c26;
  --text-primary: #f2f2f5;
  --text-secondary: #b7b8c4;
  --accent: #6d63ea;
  --accent-hover: #857bf0;
  --accent-soft: rgba(109, 99, 234, 0.16);
  --border-color: #33333f;
  --nav-bg: #0b0b12;
  --nav-text: #f2f2f5;
  --nav-text-muted: #8f91a8;
  --shadow: 0 4px 10px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 16px 36px rgba(0, 0, 0, 0.55);
  --shadow-nav: 0 2px 16px rgba(0, 0, 0, 0.5);
}

/* ==================== RESET & BASE ==================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: var(--transition);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: 0;
  left: 0;
  transform: translateY(-120%);
  background-color: var(--accent);
  color: #ffffff;
  padding: 0.75rem 1.25rem;
  border-radius: 0 0 6px 0;
  font-weight: 600;
  z-index: 2000;
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

/* ==================== TYPOGRAPHY ==================== */
h1, h2, h3 {
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

h1 {
  font-size: 3rem;
  line-height: 1.15;
}

h2 {
  font-size: 2rem;
  color: var(--text-primary);
}

h3 {
  font-size: 1.25rem;
}

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

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

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

.section-title {
  text-align: center;
  margin-bottom: 2.5rem;
}

/* ==================== BUTTONS ==================== */
.button-primary {
  background-color: var(--accent);
  color: #ffffff;
  padding: 0.9rem 2.2rem;
  font-size: 1rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: var(--transition);
}

.button-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-3px);
  box-shadow: 0 10px 20px var(--accent-soft);
}

.button-ghost {
  background: none;
  border: 1.5px solid var(--nav-text-muted);
  color: var(--nav-text);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  transition: var(--transition);
}

.button-ghost:hover {
  background-color: var(--nav-text);
  border-color: var(--nav-text);
  color: var(--nav-bg);
}

.button-secondary {
  display: inline-block;
  background: none;
  border: 1.5px solid var(--accent);
  color: var(--accent);
  padding: 0.85rem 2.1rem;
  font-size: 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  transition: var(--transition);
}

.button-secondary:hover {
  background-color: var(--accent);
  color: #ffffff;
  text-decoration: none;
}

/* ==================== HEADER & NAVIGATION ==================== */
header {
  position: sticky;
  top: 0;
  background-color: var(--nav-bg);
  z-index: 1000;
  box-shadow: var(--shadow-nav);
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 1rem;
  padding-bottom: 1rem;
}

.logo {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--nav-text);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  color: var(--nav-text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--nav-text);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--nav-text);
  position: relative;
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 2px;
  background-color: #8b80f5;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--nav-text);
  border-radius: 2px;
  transition: var(--transition);
}

.navbar.open .nav-toggle span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.navbar.open .nav-toggle span:nth-child(2) {
  opacity: 0;
}

.navbar.open .nav-toggle span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ==================== MAIN CONTENT ==================== */
section {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--border-color);
  scroll-margin-top: var(--nav-height);
}

section:last-of-type {
  border-bottom: none;
}

/* ==================== HERO SECTION ==================== */
.hero {
  display: flex;
  justify-content: center;
  padding: 5rem 0;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  min-height: 520px;
}

.hero-content {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.hero h1 {
  font-size: 3.25rem;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
  color: var(--text-primary);
  opacity: 0.75;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* ==================== ABOUT SECTION ==================== */
.about {
  background-color: var(--bg-secondary);
}

.about p {
  font-size: 1.05rem;
  margin-bottom: 1.75rem;
  line-height: 1.8;
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.skills h3 {
  margin-bottom: 1.25rem;
  text-align: center;
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 0.85rem;
}

.skills-grid span {
  display: block;
  background-color: var(--bg-primary);
  padding: 0.75rem 1.1rem;
  border-radius: 6px;
  text-align: center;
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--accent);
  border: 1.5px solid var(--border-color);
  transition: var(--transition);
}

.skills-grid span:hover {
  background-color: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
  transform: translateY(-2px);
}

/* ==================== PROJECTS SECTION ==================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.75rem;
}

.project-card {
  background-color: var(--bg-primary);
  padding: 1.75rem;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
}

.project-media {
  position: relative;
  aspect-ratio: 16 / 9;
  margin: -1.75rem -1.75rem 1.25rem;
  background-color: var(--bg-secondary);
}

.project-screenshot,
.project-demo {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.project-demo {
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}

.project-card:hover .project-demo {
  opacity: 1;
}

.project-card h3 {
  color: var(--accent);
  margin-bottom: 0.7rem;
}

.project-card p {
  margin-bottom: 1rem;
  flex-grow: 1;
}

.tech-stack {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-style: italic;
  margin-bottom: 1rem !important;
}

.project-links {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.project-card a {
  color: var(--accent);
  font-weight: 600;
  display: inline-block;
  padding: 0.4rem 0;
  border-bottom: 2px solid transparent;
  transition: var(--transition);
}

.project-card a:hover {
  border-bottom-color: var(--accent);
  text-decoration: none;
}

/* ==================== CERTIFICATES SECTION ==================== */
.certificates {
  background-color: var(--bg-secondary);
}

.cert-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.75rem;
}

.cert-item {
  background-color: var(--bg-primary);
  padding: 1.75rem;
  border-radius: 10px;
  border-left: 4px solid var(--accent);
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.cert-item:hover {
  box-shadow: var(--shadow-lg);
  transform: translateX(4px);
}

.cert-item h3 {
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.cert-item p {
  font-size: 0.92rem;
  margin-bottom: 0.25rem;
}

/* ==================== CONTACT SECTION ==================== */
.contact {
  text-align: center;
}

.contact > .container > p {
  margin-bottom: 2rem;
  font-size: 1.05rem;
}

.contact-form {
  max-width: 560px;
  margin: 0 auto 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  text-align: left;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-input {
  padding: 0.9rem 1rem;
  border: 1.5px solid var(--border-color);
  border-radius: 6px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
  transition: var(--transition);
}

.form-input::placeholder {
  color: var(--text-secondary);
}

.form-input:hover {
  border-color: var(--accent);
}

.form-input:focus {
  outline: none;
  border-color: var(--accent);
  background-color: var(--bg-primary);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.contact-form .button-primary {
  width: 100%;
}

.contact-info {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.contact-info p {
  margin: 0;
}

.contact-info a {
  margin: 0 0.25rem;
}

/* ==================== FOOTER ==================== */
footer {
  background-color: var(--nav-bg);
  text-align: center;
  padding: 1.75rem;
  color: var(--nav-text-muted);
}

/* ==================== RESPONSIVE DESIGN ==================== */
@media (max-width: 768px) {
  :root {
    --nav-height: 68px;
  }

  .navbar {
    flex-wrap: wrap;
    padding: 1rem 0;
  }

  .nav-toggle {
    display: flex;
    order: 2;
  }

  #theme-toggle {
    display: none;
    order: 4;
    margin: 0 auto;
  }

  .nav-links {
    display: none;
    order: 3;
    flex-direction: column;
    gap: 1rem;
    width: 100%;
    text-align: center;
    padding-top: 1rem;
  }

  .navbar.open .nav-links,
  .navbar.open #theme-toggle {
    display: flex;
  }

  h1 {
    font-size: 2rem;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

  .hero {
    min-height: 380px;
    padding: 3.5rem 0;
  }

  h2 {
    font-size: 1.5rem;
  }

  .projects-grid,
  .cert-list {
    grid-template-columns: 1fr;
  }

  .contact-info {
    flex-direction: column;
    gap: 1rem;
  }

  .container {
    padding: 0 1.25rem;
  }

  section {
    padding: 2.5rem 0;
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.2rem;
  }

  .hero h1 {
    font-size: 1.8rem;
  }

  .nav-links {
    gap: 0.5rem;
  }

  .skills-grid {
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 0.5rem;
  }

  .button-primary {
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
  }
}