* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Poppins', sans-serif;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    body {
      background: #0d0d0d;
      color: white;
      transition: background 0.5s, color 0.5s;
      scroll-behavior: smooth;
    }

    header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 15px 60px;
      position: sticky;
      top: 0;
      z-index: 100;
      transition: background 0.5s, color 0.5s;
      background: linear-gradient(to bottom, rgba(20,20,20,0.95), rgba(20,20,20,0));
    }

    .light-mode header {
      background: linear-gradient(to bottom, rgba(255,255,255,0.95), rgba(255,255,255,0));
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 10px;
    }

    nav ul {
      list-style: none;
      display: flex;
      gap: 40px;
      align-items: center;
    }

    nav ul li a {
      color: inherit;
      text-decoration: none;
      font-size: 1rem;
      font-weight: 500;
      position: relative;
      transition: color 0.3s ease;
    }

    nav ul li a::after {
      content: "";
      position: absolute;
      width: 0;
      height: 2px;
      background: currentColor;
      left: 0;
      bottom: -6px;
      transition: width 0.4s ease 0.15s;
    }

    nav ul li a:hover::after,
    nav ul li a.active::after {
      width: 100%;
      background: #4caf50;
    }

    nav ul li a:hover {
      color: #cccccc;
    }

    .toggle-btn {
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .toggle-btn i,
    .toggle-btn svg {
      width: 24px;
      height: 24px;
      stroke-width: 2.2;
      transition: transform 0.5s ease, opacity 0.5s ease, stroke 0.5s ease;
    }

    /* Hero Section */
    .hero {
      display: flex;
      justify-content: flex-start;
      align-items: flex-start;
      height: 80vh;
      padding-left: 8%;
      text-align: left;
      position: relative;
      overflow: hidden;
      flex-direction: column;
    }

    .hero-left {
      width: 50%;
      margin-top: 60px;
      font-size: 2.5rem;
      font-weight: 600;
      z-index: 2;
      position: relative;
    }

    .hero-sub {
      width: 50%;
      margin-top: 10px;
      font-size: 1.2rem;
      font-weight: 500;
      line-height: 1.6;
      color: white;
      white-space: pre-line;
      min-height: 4.5em;
      z-index: 2;
      position: relative;
    }

    .hero-image {
      position: fixed;
      right: -5%;
      top: 0;
      height: 100vh;
      width: 65%;
      background: url('hero-pic.jpg') no-repeat center center;
      background-size: cover;
      opacity: 0.55;
      pointer-events: none;
      z-index: 1;
      mask-image: linear-gradient(to left, rgba(0,0,0,1) 40%, rgba(0,0,0,0) 100%), 
                  linear-gradient(to bottom, rgba(0,0,0,0), rgba(0,0,0,1), rgba(0,0,0,0));
      -webkit-mask-image: linear-gradient(to left, rgba(0,0,0,1) 40%, rgba(0,0,0,0) 100%), 
                          linear-gradient(to bottom, rgba(0,0,0,0), rgba(0,0,0,1), rgba(0,0,0,0));
      mask-composite: intersect;
      -webkit-mask-composite: destination-in;
      transition: opacity 0.2s ease-out;
    }

    .light-mode {
      background: white;
      color: black;
    }

    .light-mode nav ul li a:hover {
      color: #555;
    }

    .light-mode .hero-left,
    .light-mode .hero-sub {
      color: black;
    }

    /* Download Resume */
    .download-resume {
      display: inline-block;
      margin-top: 20px;
      font-size: 1.1rem;
      font-weight: 500;
      color: #4caf50;
      text-decoration: none;
      opacity: 0;
      transform: translateY(20px);
      transition: text-shadow 0.3s, color 0.3s, opacity 0.6s ease, transform 0.6s ease;
    }

    .download-resume:hover {
      color: #39ff14;
      text-shadow: 0 0 10px #39ff14, 0 0 20px #39ff14, 0 0 30px #39ff14;
    }

    .show-resume {
      opacity: 1 !important;
      transform: translateY(0) !important;
    }

    /* Security Quote */
    #security-quote {
      margin-top: 12px;
      font-size: 1.4rem;
      font-style: italic;
      opacity: 0;
      transition: opacity 0.8s ease, color 0.5s ease;
    }

    .light-mode #security-quote {
      color: black;
    }

    /* Education & Certifications Sections */
    .education-section {
      padding-top: 80px;
      padding-left: 8%;
      padding-right: 8%;
      padding-bottom: 100px;
      background: #111;
      color: white;
      position: relative;
      overflow: hidden;
    }

    .light-mode .education-section {
      background: #f9f9f9;
      color: black;
    }

    .education-title {
      font-size: 2.5rem;
      font-weight: 600;
      text-align: center;
      margin-bottom: 50px;
      opacity: 0;
      transform: translateY(30px);
      transition: all 0.8s ease;
    }

    /* Timeline */
    .timeline {
      position: relative;
      margin: 0 auto;
      max-width: 800px;
      padding-left: 40px;
    }

    .timeline::before {
      content: '';
      position: absolute;
      left: 20px;
      top: 0;
      width: 4px;
      height: 100%;
      background: #888;
    }

    .timeline-event {
      position: relative;
      margin-bottom: 50px;
      opacity: 0;
      transform: translateY(30px);
      transition: all 0.6s ease;
      display: flex;
      align-items: flex-start;
    }

    .timeline-event .dot {
      position: absolute;
      left: 12px;
      width: 16px;
      height: 16px;
      background: #4caf50;
      border-radius: 50%;
      top: 0;
    }

    .timeline-event .event-content {
      margin-left: 50px;
    }

    .timeline-event h3 {
      font-size: 1.3rem;
      margin-bottom: 5px;
    }

    .timeline-event p {
      font-size: 1rem;
      line-height: 1.5;
    }

    /* Certificates Grid */
    .certificates-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 30px;
      max-width: 900px;
      margin: 0 auto;
      padding-top: 40px;
    }

    .certificate {
      background: #1a1a1a;
      padding: 15px;
      border-radius: 12px;
      text-align: center;
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }

    .certificate img {
      width: 100%;
      max-height: 200px;
      object-fit: contain;
      border-radius: 8px;
      margin-bottom: 10px;
    }

    .certificate p {
      font-size: 1rem;
      font-weight: 500;
      color: white;
    }

    .certificate:hover {
      transform: translateY(-5px);
      box-shadow: 0 10px 20px rgba(76, 175, 80, 0.5);
    }

    .light-mode .certificate {
      background: #f0f0f0;
    }

    .light-mode .certificate p {
      color: #111;
    }

    .show {
      opacity: 1 !important;
      transform: translateY(0) !important;
    }

    .education-title.show {
      transform: translateY(0) !important;
    }

    #backToTop {
      position: fixed;
      bottom: 30px;
      right: 30px;
      width: 50px;
      height: 50px;
      background: rgba(50, 50, 50, 0.8);
      color: white;
      border: none;
      border-radius: 8px;
      cursor: pointer;
      display: flex;
      justify-content: center;
      align-items: center;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease, background 0.3s ease;
      z-index: 100;
    }

    .light-mode #backToTop {
      background: rgba(200, 200, 200, 0.8);
      color: black;
    }

    #backToTop.show {
      opacity: 1;
      pointer-events: auto;
    }

    #backToTop:hover {
      background: rgba(76, 175, 80, 0.9);
    }

    .skills-container {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  justify-content: center;
  padding-top: 40px;
}

.skill {
  background: #1a1a1a;
  color: white;
  font-weight: 500;
  font-size: 1rem;
  padding: 10px 18px;
  border-radius: 25px;
  cursor: default;
  opacity: 0;
  transform: translateY(30px) scale(0.9);
  transition: all 0.5s ease;
  box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

.light-mode .skill {
  background: #e0e0e0;
  color: #111;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.skill.show {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.skill:hover {
  transform: scale(1.1);
  background: #4caf50;
  color: #fff;
  box-shadow: 0 6px 15px rgba(76,175,80,0.5);
}

.contact-card {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 50px;
  background: rgba(17, 17, 17, 0.9); /* slightly transparent */
  border-radius: 20px;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  opacity: 0.3; /* slightly visible initially */
  transform: translateY(30px);
  transition: all 0.8s ease, box-shadow 0.3s ease;
  box-shadow: 0 8px 25px rgba(0,0,0,0.4); /* soft shadow */
}

.light-mode .contact-card {
  background: rgba(240, 240, 240, 0.9);
  box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.contact-left {
  font-size: 2.5rem;
  font-weight: 600;
  color: white;
  min-height: 3em; /* reserve height so typing doesn't jump layout */
}

.light-mode .contact-left {
  color: black;
}

.contact-right p {
  margin: 10px 0;
  font-size: 1.2rem;
  color: white;
}

.light-mode .contact-right p {
  color: black;
}

.contact-card.show .contact-left,
.contact-card.show .contact-right {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.2s; /* staggered */
}

.contact-right a {
  color: #4caf50;
  text-decoration: none;
}

.contact-right a:hover {
  text-decoration: underline;
  color: #39ff14;
}
.contact-card.show {
  opacity: 1;
  transform: translateY(0);
  box-shadow: 0 12px 35px rgba(76,175,80,0.5); /* stronger shadow on reveal */
}