/* ============================================
   PORTFOLIO - Java Backend Developer
   Main Stylesheet
   Color Scheme: Blue (#2563EB) + Dark (#0F172A)
   Font: Inter (Google Fonts)
   ============================================ */

/* --- CSS Variables & Reset --- */
:root {
  --primary: #2563EB;
  --primary-light: #3B82F6;
  --primary-dark: #1D4ED8;
  --accent: #06B6D4;
  --bg-dark: #0F172A;
  --bg-card: #1E293B;
  --bg-card-hover: #263450;
  --text-primary: #F1F5F9;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --border: #334155;
  --gradient-hero: linear-gradient(135deg, #0F172A 0%, #1E293B 50%, #0F172A 100%);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.3);
  --shadow-glow: 0 0 30px rgba(37,99,235,0.15);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --radius: 16px;
  --radius-sm: 10px;
  --nav-scrolled-bg: rgba(15, 23, 42, 0.92);
  --nav-mobile-bg: rgba(15, 23, 42, 0.98);
  --skill-bar-bg: rgba(100,116,139,0.2);
  --input-bg: rgba(100,116,139,0.1);
  --section-alt-bg: rgba(30,41,59,0.3);
  --overlay-bg: rgba(15,23,42,0.7);
}

/* --- Light Mode Variables --- */
[data-theme="light"] {
  --bg-dark: #F8FAFC;
  --bg-card: #FFFFFF;
  --bg-card-hover: #F1F5F9;
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --text-muted: #94A3B8;
  --border: #E2E8F0;
  --gradient-hero: linear-gradient(135deg, #F8FAFC 0%, #EFF6FF 50%, #F8FAFC 100%);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.08);
  --shadow-glow: 0 0 30px rgba(37,99,235,0.1);
  --nav-scrolled-bg: rgba(248, 250, 252, 0.92);
  --nav-mobile-bg: rgba(248, 250, 252, 0.98);
  --skill-bar-bg: rgba(148,163,184,0.2);
  --input-bg: rgba(241,245,249,0.8);
  --section-alt-bg: rgba(241,245,249,0.6);
  --overlay-bg: rgba(248,250,252,0.8);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  transition: background 0.4s ease, color 0.4s ease;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Section Common --- */
.section {
  padding: 100px 0;
  position: relative;
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 12px;
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 560px;
  margin: 0 auto;
}

.section-divider {
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  margin: 16px auto 0;
}

/* --- Fade-in Animation --- */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 16px 0;
  transition: var(--transition);
  background: transparent;
}

.navbar.scrolled {
  background: var(--nav-scrolled-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
  box-shadow: var(--shadow-card);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* --- Theme Toggle Button --- */
.theme-toggle {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  border: 1.5px solid var(--border);
  background: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
  margin-left: 16px;
}

.theme-toggle:hover {
  border-color: var(--primary-light);
  background: rgba(37,99,235,0.08);
  transform: scale(1.05);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  position: absolute;
  transition: transform 0.4s ease, opacity 0.4s ease;
  line-height: 1;
}

/* Dark mode: show sun icon, hide moon */
.theme-toggle .icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}
.theme-toggle .icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

/* Light mode: show moon icon, hide sun */
[data-theme="light"] .theme-toggle .icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}
[data-theme="light"] .theme-toggle .icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.nav-logo span {
  color: var(--primary-light);
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 4px 0;
  transition: color var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-light);
  transition: width var(--transition);
  border-radius: 1px;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

/* Hamburger Menu */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 26px;
  height: 2.5px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

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

.nav-toggle.active span:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  background: var(--gradient-hero);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, rgba(37,99,235,0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -15%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(6,182,212,0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.08;
  pointer-events: none;
}

.hero .container {
  display: flex;
  align-items: center;
  gap: 80px;
  position: relative;
  z-index: 2;
}

.hero-content {
  flex: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(37,99,235,0.12);
  border: 1px solid rgba(37,99,235,0.25);
  color: var(--primary-light);
  padding: 8px 18px;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  letter-spacing: 0.5px;
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  background: #22C55E;
  border-radius: 50%;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.3); }
}

.hero-content h1 {
  font-size: 3.8rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 10px;
  letter-spacing: -1.5px;
}

.hero-content h1 .highlight {
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-content .subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  max-width: 520px;
  line-height: 1.7;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 12px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  font-family: inherit;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  box-shadow: 0 4px 20px rgba(37,99,235,0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(37,99,235,0.5);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1.5px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--primary-light);
  background: rgba(37,99,235,0.08);
  transform: translateY(-2px);
}

/* Hero Image */
.hero-image {
  flex-shrink: 0;
  position: relative;
}

.hero-avatar-wrapper {
  width: 360px;
  height: 360px;
  border-radius: 50%;
  padding: 5px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  position: relative;
  animation: float 6s ease-in-out infinite;
}

.hero-avatar-wrapper img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
  border: 5px solid var(--bg-dark);
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-16px); }
}

.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.stat-item h3 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary-light);
}

.stat-item p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* ============================================
   ABOUT SECTION
   ============================================ */
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.about-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 28px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.about-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  opacity: 0;
  transition: opacity var(--transition);
}

.about-card:hover {
  transform: translateY(-6px);
  border-color: rgba(37,99,235,0.3);
  box-shadow: var(--shadow-glow);
}

.about-card:hover::before {
  opacity: 1;
}

.about-icon {
  width: 56px;
  height: 56px;
  background: rgba(37,99,235,0.1);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
  transition: var(--transition);
}

.about-card:hover .about-icon {
  background: rgba(37,99,235,0.2);
  transform: scale(1.05);
}

.about-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.about-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ============================================
   SKILLS SECTION
   ============================================ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.skill-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 24px 28px;
  transition: var(--transition);
}

.skill-item:hover {
  border-color: rgba(37,99,235,0.3);
  box-shadow: var(--shadow-glow);
}

.skill-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.skill-info .skill-name {
  font-weight: 600;
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.skill-info .skill-name span.icon {
  font-size: 1.3rem;
}

.skill-info .skill-percent {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--primary-light);
}

.skill-bar {
  width: 100%;
  height: 8px;
  background: var(--skill-bar-bg);
  border-radius: 4px;
  overflow: hidden;
}

.skill-bar-fill {
  height: 100%;
  border-radius: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  width: 0;
  transition: width 1.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   PROJECTS SECTION
   ============================================ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  transform: translateY(-8px);
  border-color: rgba(37,99,235,0.3);
  box-shadow: var(--shadow-glow);
}

.project-thumb {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.project-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.project-card:hover .project-thumb img {
  transform: scale(1.08);
}

.project-overlay {
  position: absolute;
  inset: 0;
  background: var(--overlay-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  opacity: 0;
  transition: opacity var(--transition);
}

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

.project-overlay a {
  width: 44px;
  height: 44px;
  background: var(--primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.1rem;
  transition: var(--transition);
  transform: translateY(10px);
}

.project-card:hover .project-overlay a {
  transform: translateY(0);
}

.project-overlay a:hover {
  background: var(--primary-dark);
  transform: scale(1.1) !important;
}

.project-body {
  padding: 24px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.project-body h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.project-body p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 16px;
  flex: 1;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.project-tags span {
  background: rgba(37,99,235,0.1);
  color: var(--primary-light);
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 0.78rem;
  font-weight: 600;
}

/* ============================================
   CONTACT SECTION
   ============================================ */
.contact-wrapper {
  display: grid;
  grid-template-columns: 1fr 1.3fr;
  gap: 40px;
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.contact-info-card {
  display: flex;
  align-items: center;
  gap: 18px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 22px 24px;
  transition: var(--transition);
}

.contact-info-card:hover {
  border-color: rgba(37,99,235,0.3);
  transform: translateX(6px);
}

.contact-info-card .icon-box {
  width: 50px;
  height: 50px;
  background: rgba(37,99,235,0.1);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.contact-info-card h4 {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 2px;
}

.contact-info-card p {
  font-size: 0.95rem;
  font-weight: 600;
}

.contact-form {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 16px;
}

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

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
  background: var(--input-bg);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  transition: var(--transition);
  outline: none;
  resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
}

.form-group.full {
  margin-bottom: 16px;
}

.contact-form .btn-primary {
  width: 100%;
  justify-content: center;
  padding: 16px;
  font-size: 1rem;
  margin-top: 8px;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: rgba(15,23,42,0.6);
  border-top: 1px solid var(--border);
  padding: 40px 0;
  text-align: center;
}

.footer-socials {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 20px;
}

.footer-socials a {
  width: 44px;
  height: 44px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  transition: var(--transition);
}

.footer-socials a:hover {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  transform: translateY(-3px);
}

.footer p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer p span {
  color: var(--primary-light);
  font-weight: 600;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .hero .container { gap: 40px; }
  .hero-content h1 { font-size: 3rem; }
  .hero-avatar-wrapper { width: 280px; height: 280px; }
  .projects-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .section { padding: 70px 0; }
  .section-header h2 { font-size: 2rem; }

  /* Navbar mobile */
  .nav-toggle { display: flex; }
  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--nav-mobile-bg);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 100px 40px 40px;
    gap: 24px;
    transition: right var(--transition);
    border-left: 1px solid var(--border);
  }
  .nav-links.open { right: 0; }
  .nav-links a { font-size: 1.1rem; }

  /* Hero mobile */
  .hero .container {
    flex-direction: column-reverse;
    text-align: center;
    gap: 40px;
    padding-top: 100px;
  }
  .hero-content h1 { font-size: 2.4rem; }
  .hero-content .subtitle { margin: 0 auto 28px; }
  .hero-buttons { justify-content: center; }
  .hero-avatar-wrapper { width: 220px; height: 220px; }
  .hero-stats { justify-content: center; gap: 28px; }

  /* Grids mobile */
  .about-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .contact-wrapper { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .hero-content h1 { font-size: 1.9rem; }
  .hero-avatar-wrapper { width: 180px; height: 180px; }
  .hero-stats { flex-direction: column; gap: 16px; align-items: center; }
  .btn { padding: 12px 24px; font-size: 0.9rem; }
}