/* ======================================================
   LUXURY TECH MONOCHROME DESIGN SYSTEM — CERTIFICATIONS
   Crafted to Apple, Linear, Stripe & OpenAI Interface Standards
   Palette: Day Theme / High-Contrast Obsidian & Crisp Zinc
   Fully Responsive: Mobile (320px) -> 4K Ultra-Wide
====================================================== */

:root {
  --bg-body: #fafafa;
  --bg-card: #ffffff;
  --bg-subtle: #f4f4f5;
  --bg-glass: rgba(255, 255, 255, 0.85);

  --border-card: #e4e4e7;
  --border-card-subtle: #f1f1f4;
  --border-hover: #09090b;

  --text-main: #09090b;
  --text-body: #3f3f46;
  --text-muted: #71717a;
  --text-light: #a1a1aa;

  --primary-btn: #09090b;
  --primary-btn-hover: #18181b;

  /* Beautiful Layered Shadows */
  --shadow-sm: 0px 2px 3px -1px rgba(0,0,0,0.06), 0px 1px 0px 0px rgba(0,0,0,0.02), 0px 0px 0px 1px rgba(0,0,0,0.04);
  --shadow-card: 0px 0px 0px 1px rgba(0,0,0,0.06), 0px 1px 2px -0.5px rgba(0,0,0,0.04), 0px 3px 6px -1.5px rgba(0,0,0,0.03);
  --shadow-hover: 0px 0px 0px 1px rgba(9,9,11,0.12), 0px 3px 6px -1px rgba(0,0,0,0.05), 0px 8px 16px -3px rgba(0,0,0,0.06), 0px 20px 32px -6px rgba(0,0,0,0.05);

  --ease-spring: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-micro: 0.15s;
  --duration-ui: 0.22s;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Plus Jakarta Sans', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ================= RESET ================= */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  scroll-behavior: smooth;
  -webkit-tap-highlight-color: transparent;
}

/* Custom Sleek Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.16);
  border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(0, 0, 0, 0.32);
}
* {
  scrollbar-width: thin;
  scrollbar-color: rgba(0, 0, 0, 0.16) transparent;
}

body {
  font-family: var(--font-sans);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  background: var(--bg-body);
  color: var(--text-main);
  min-height: 100vh;
}

::selection {
  background: #09090b;
  color: #ffffff;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  color: var(--text-main);
  letter-spacing: -0.03em;
  font-weight: 700;
  line-height: 1.28;
}

section {
  max-width: 1200px;
  margin: auto;
  padding: clamp(36px, 5vw, 64px) clamp(16px, 4vw, 28px);
}

/* ================= NAVBAR ================= */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 clamp(16px, 3.5vw, 32px);
  height: 64px;
  background: var(--bg-glass);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid rgba(0, 0, 0, 0.07);
  transition-property: background-color, border-color, box-shadow;
  transition-duration: var(--duration-ui);
  transition-timing-function: ease;
}

.logo {
  font-size: clamp(16px, 2.2vw, 18px);
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* BACK BUTTON */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: #ffffff;
  color: var(--text-main);
  border: 1px solid var(--border-card);
  border-radius: 8px;
  padding: 7px 15px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
  min-height: 38px;
  box-shadow: var(--shadow-sm);
  transition-property: transform, border-color, background-color, box-shadow;
  transition-duration: var(--duration-ui);
  transition-timing-function: var(--ease-spring);
}

.back-btn:hover {
  border-color: #09090b;
  background: #fdfdfd;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.back-btn:active {
  transform: scale(0.96);
}

/* ================= HERO ================= */
.hero {
  text-align: center;
  padding: clamp(36px, 5vw, 56px) 16px clamp(24px, 4vw, 36px);
}

.hero h1 {
  font-size: clamp(28px, 4.4vw, 44px);
  font-weight: 700;
  letter-spacing: -0.035em;
  margin-bottom: 10px;
}

.hero p {
  color: var(--text-muted);
  font-size: clamp(14px, 2vw, 16px);
  font-weight: 500;
}

/* ================= CERTIFICATIONS CONTAINER ================= */
.certifications {
  display: flex;
  flex-direction: column;
  gap: clamp(24px, 3.5vw, 36px);
  padding-top: 0;
}

/* ================= CERT CARD ================= */
.cert-box {
  display: flex;
  align-items: center;
  gap: clamp(24px, 4vw, 48px);
  padding: clamp(20px, 3.5vw, 36px);
  border-radius: 18px;
  background: #ffffff;
  border: 1px solid var(--border-card);
  box-shadow: var(--shadow-card);
  transition-property: transform, box-shadow, border-color, opacity;
  transition-duration: 0.5s, var(--duration-ui), var(--duration-ui), 0.5s;
  transition-timing-function: var(--ease-spring);
  position: relative;
  overflow: hidden;
  opacity: 0;
  transform: translateY(20px);
  will-change: opacity, transform;
}

.cert-box.show {
  opacity: 1;
  transform: translateY(0);
}

.cert-box.show:hover {
  transform: translateY(-3px);
  border-color: #09090b;
  box-shadow: var(--shadow-hover);
}

/* ================= IMAGE FRAME ================= */
.cert-image {
  flex: 1;
  min-width: 280px;
  max-width: 440px;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid rgba(0, 0, 0, 0.08);
  background: #f4f4f5;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.cert-image img {
  width: 100%;
  height: 100%;
  max-height: 290px;
  object-fit: cover;
  display: block;
  transition: transform 0.4s var(--ease-spring);
}

.cert-box:hover .cert-image img {
  transform: scale(1.025);
}

/* ================= CONTENT ================= */
.cert-content {
  flex: 1.25;
  min-width: 280px;
  display: flex;
  flex-direction: column;
}

.cert-content h3 {
  font-size: clamp(20px, 2.4vw, 24px);
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: 8px;
  color: var(--text-main);
}

.issuer {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-card);
  border-radius: 6px;
  color: var(--text-body);
  font-size: 12px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  margin-bottom: 14px;
  align-self: flex-start;
}

.cert-content p {
  color: var(--text-body);
  font-size: 14.5px;
  line-height: 1.62;
  margin-bottom: 14px;
}

.cert-content h4 {
  font-size: 12.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-top: 6px;
  margin-bottom: 8px;
}

.cert-list {
  padding-left: 0;
  margin-bottom: 14px;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 6px 12px;
}

.cert-list li {
  font-size: 13.5px;
  color: var(--text-body);
  position: relative;
  padding-left: 16px;
  line-height: 1.5;
}

.cert-list li::before {
  content: "•";
  position: absolute;
  left: 2px;
  top: 0;
  color: #09090b;
  font-weight: 700;
  font-size: 14px;
}

.skills {
  font-size: 13px;
  color: var(--text-body);
  background: var(--bg-subtle);
  border: 1px solid var(--border-card);
  padding: 8px 12px;
  border-radius: 8px;
  margin-bottom: 18px;
  line-height: 1.55;
}

/* ================= BUTTON SYSTEM ================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  background: var(--primary-btn);
  color: #ffffff;
  border-radius: 8px;
  border: 1px solid var(--primary-btn);
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  transition-property: transform, background-color, border-color, box-shadow;
  transition-duration: var(--duration-ui);
  transition-timing-function: var(--ease-spring);
  min-height: 38px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.18), 0 2px 4px rgba(0, 0, 0, 0.12);
  white-space: nowrap;
}

.btn:hover {
  background: var(--primary-btn-hover);
  border-color: var(--primary-btn-hover);
  transform: translateY(-1px);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.25), 0 4px 12px rgba(0, 0, 0, 0.18);
}

.btn:active {
  transform: scale(0.96);
}

/* Secondary Button styling when next to primary */
.btn:nth-of-type(2) {
  background: #ffffff;
  color: var(--text-main);
  border: 1px solid var(--border-card);
  box-shadow: var(--shadow-sm);
}

.btn:nth-of-type(2):hover {
  background: var(--bg-subtle);
  border-color: #09090b;
  color: #09090b;
}

/* ================= FOOTER ================= */
footer {
  background: #ffffff;
  border-top: 1px solid var(--border-card);
  text-align: center;
  padding: clamp(28px, 4vw, 40px) 20px;
  color: var(--text-muted);
  font-size: 13.5px;
  padding-bottom: max(28px, env(safe-area-inset-bottom));
}

/* ================= RESPONSIVE DESIGN (ALL SCREENS & RETINA / IOS) ================= */
@media (max-width: 960px) {
  .cert-box {
    flex-direction: column;
    align-items: stretch;
    gap: 22px;
    padding: 24px;
  }

  .cert-image {
    max-width: 100%;
    width: 100%;
  }

  .cert-image img {
    max-height: 340px;
    width: 100%;
  }

  .cert-content {
    width: 100%;
  }
}

@media (max-width: 600px) {
  section {
    padding: 28px 14px;
  }

  .navbar {
    padding: 0 14px;
    height: 58px;
  }

  .logo {
    font-size: 15px;
  }

  .back-btn {
    padding: 6px 12px;
    font-size: 12px;
    min-height: 34px;
  }

  .hero {
    padding: 24px 8px 16px;
  }

  .hero h1 {
    font-size: 24px;
  }

  .hero p {
    font-size: 13.5px;
  }

  .cert-box {
    padding: 16px;
    border-radius: 14px;
    gap: 16px;
  }

  .cert-content h3 {
    font-size: 18px;
  }

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

  .btn {
    width: 100%;
    margin-right: 0;
    margin-top: 8px;
  }
}