/* ==========================================================================
   Kirschberg 684–inspired premium aesthetic
   Typography: Playfair Display (serif) + Inter (sans)
   Palette: off-white, warm greys, charcoal, deep black
   Grid: rigid layout with subtle 1px borders
   ========================================================================== */

:root {
  /* Neutral palette – refined, architectural */
  --off-white: #FAFAF8;
  --cream: #F5F3EF;
  --warm-grey-100: #E8E6E2;
  --warm-grey-200: #D4D1CC;
  --warm-grey-300: #9E9B96;
  --charcoal: #3D3A36;
  --ink: #1A1917;
  --black: #0D0C0B;

  /* Grid & borders – blueprint-like */
  --grid-line: 1px solid rgba(26, 25, 23, 0.08);
  --grid-line-strong: 1px solid rgba(26, 25, 23, 0.14);
  --grid-gap: clamp(1rem, 3vw, 2rem);
  --page-width: min(90vw, 72rem);

  /* Transitions */
  --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
  --duration-fast: 0.25s;
  --duration-mid: 0.4s;
  --duration-slow: 0.65s;

  /* Shadows – minimal */
  --shadow-subtle: 0 2px 16px rgba(13, 12, 11, 0.04);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--charcoal);
  background: var(--off-white);
  margin: 0;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

.app { min-height: 100vh; display: flex; flex-direction: column; }

/* --------------------------------------------------------------------------
   Grid system – implied rigid structure
   -------------------------------------------------------------------------- */
.grid-container {
  width: var(--page-width);
  max-width: 72rem;
  margin: 0 auto;
  padding: 0 var(--grid-gap);
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
}

/* --------------------------------------------------------------------------
   Header – minimalist, sparse horizontal nav
   -------------------------------------------------------------------------- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: rgba(250, 250, 248, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: var(--grid-line);
}

.nav {
  width: var(--page-width);
  max-width: 72rem;
  margin: 0 auto;
  padding: 1.25rem var(--grid-gap);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--grid-gap);
}

.logo {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1rem;
  font-weight: 500;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: 0.02em;
  position: relative;
  transition: color var(--duration-fast) var(--ease-out-expo);
}

.logo::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 0;
  height: 1px;
  background: var(--ink);
  transition: width var(--duration-mid) var(--ease-out-expo);
}

.logo:hover::after,
.logo:focus-visible::after { width: 100%; }

/* Hamburger for mobile */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 0.5rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--ink);
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: currentColor;
  transition: transform var(--duration-mid), opacity var(--duration-fast);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

.nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--warm-grey-300);
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  position: relative;
  padding: 0.25rem 0;
  transition: color var(--duration-fast) var(--ease-out-expo);
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 1px;
  background: var(--ink);
  transition: width var(--duration-mid) var(--ease-out-expo);
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--ink);
}

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

/* Language toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: 0.5rem;
  padding-left: 1rem;
  border-left: var(--grid-line);
}
.lang-btn {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--warm-grey-300);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  transition: color var(--duration-fast);
}
.lang-btn:hover { color: var(--charcoal); }
.lang-btn.is-active { color: var(--ink); font-weight: 600; }
.lang-sep {
  color: var(--warm-grey-200);
  font-size: 0.7rem;
  user-select: none;
}

.main { flex: 1; padding-top: 80px; }

/* --------------------------------------------------------------------------
   Hero – high-impact, large-scale, overlapping text
   -------------------------------------------------------------------------- */
.hero {
  position: relative;
  min-height: 90vh;
  display: flex;
  align-items: center;
  padding: 4rem var(--grid-gap) 6rem;
  overflow: hidden;
  border-bottom: var(--grid-line);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(250, 250, 248, 0.5) 0%, transparent 50%),
    radial-gradient(ellipse 70% 50% at 60% 40%, rgba(232, 230, 226, 0.4), transparent);
  pointer-events: none;
}

/* Hero image area – overlapping, large-scale */
.hero-img-container {
  position: absolute;
  top: 15%;
  right: clamp(2rem, 6vw, 8rem);
  width: min(42%, 28rem);
  aspect-ratio: 4 / 5;
  border: var(--grid-line);
  z-index: 0;
}

.hero-img-placeholder,
.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.hero-img {
  transition: transform var(--duration-slow) var(--ease-out-expo);
}

.hero-img-container:hover .hero-img { transform: scale(1.02); }

/* Asymmetric hero layout – offset content */
.hero-content {
  max-width: 52rem;
  margin: 0;
  margin-left: clamp(0, 8vw, 6rem);
  text-align: left;
  position: relative;
  z-index: 1;
}

.hero-label {
  font-family: 'Inter', sans-serif;
  font-size: 0.6875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--warm-grey-300);
  margin: 0 0 1.5rem;
  display: block;
}

.hero-title {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: clamp(2.75rem, 6vw, 4.5rem);
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin: 0 0 1.75rem;
}

.hero-desc {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--charcoal);
  max-width: 36rem;
  margin: 0 0 2rem;
}

.hero-desc .highlight {
  color: var(--ink);
  font-weight: 500;
}

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

/* Buttons – underline expansion, inverted blocks on hover */
.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.625rem 0;
  font-size: 0.8125rem;
  font-weight: 500;
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  transition: all var(--duration-mid) var(--ease-out-expo);
  position: relative;
}

.btn-primary {
  color: var(--ink);
}

.btn-primary::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--ink);
  transform-origin: left;
  transition: transform var(--duration-mid) var(--ease-out-expo);
}

.btn-primary:hover {
  color: var(--ink);
}

.btn-primary:hover::after {
  transform: scaleX(0);
  transform-origin: right;
}

.btn-glass {
  color: var(--charcoal);
  border: var(--grid-line-strong);
  padding: 0.625rem 1.25rem;
}

.btn-glass::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--ink);
  opacity: 0;
  transition: opacity var(--duration-mid) var(--ease-out-expo);
  z-index: -1;
}

.btn-glass:hover {
  color: var(--off-white);
  border-color: var(--ink);
}

.btn-glass:hover::before { opacity: 1; }

/* --------------------------------------------------------------------------
   Sections – grid structure, borders, breathing room
   -------------------------------------------------------------------------- */
.section {
  padding: clamp(4rem, 10vw, 8rem) var(--grid-gap);
  border-bottom: var(--grid-line);
}

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

.section-title {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 0.75rem;
  letter-spacing: -0.02em;
}

.section-desc {
  font-size: 0.9375rem;
  color: var(--warm-grey-300);
  max-width: 38rem;
  margin: 0 0 3rem;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Chat section
   -------------------------------------------------------------------------- */
.chat-section {
  padding: clamp(4rem, 10vw, 8rem) var(--grid-gap);
  border-bottom: var(--grid-line);
}

.chat-inner {
  max-width: 42rem;
  margin: 0 auto;
}

.chat-header-text {
  text-align: left;
  margin-bottom: 2.5rem;
}

.chat-panel {
  background: var(--cream);
  border: var(--grid-line-strong);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 420px;
  transition: box-shadow var(--duration-mid);
}

.chat-panel:hover {
  box-shadow: var(--shadow-subtle);
}

.chat-panel-header {
  padding: 1rem 1.5rem;
  border-bottom: var(--grid-line);
  background: rgba(250, 250, 248, 0.6);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.chat-title {
  font-family: 'Playfair Display', Georgia, serif;
  font-weight: 500;
  font-size: 1rem;
  color: var(--ink);
}

.chat-clear {
  font-size: 0.75rem;
  color: var(--warm-grey-300);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  transition: color var(--duration-fast);
}

.chat-clear:hover { color: var(--ink); }

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 1.25rem 1.5rem;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.chat-empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 240px;
  color: var(--warm-grey-300);
  font-size: 0.875rem;
  text-align: center;
}

.chat-empty p { margin: 0.25rem 0; }

.msg {
  display: flex;
  max-width: 85%;
}

.msg.user { align-self: flex-end; }
.msg.assistant { align-self: flex-start; }

.msg-bubble {
  padding: 0.875rem 1.125rem;
  font-size: 0.9375rem;
  line-height: 1.6;
  white-space: pre-wrap;
  border: var(--grid-line);
  transition: transform var(--duration-fast);
}

.msg.user .msg-bubble {
  background: var(--ink);
  color: var(--off-white);
  border-color: var(--ink);
}

.msg.assistant .msg-bubble {
  background: var(--off-white);
  color: var(--charcoal);
}

.msg:hover .msg-bubble {
  transform: translateY(-1px);
}

/* Typing indicator */
.typing-indicator {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 1.2em;
}

.typing-text {
  color: var(--warm-grey-300);
  font-style: italic;
  font-size: 0.9em;
}

.typing-dots { display: inline-flex; align-items: center; gap: 3px; }

.typing-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--charcoal);
  animation: typing-bounce 1.4s ease-in-out infinite both;
}

.typing-dot:nth-child(1) { animation-delay: 0s; }
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typing-bounce {
  0%, 80%, 100% { transform: scale(0.5) translateY(2px); opacity: 0.4; }
  40% { transform: scale(1) translateY(0); opacity: 1; }
}

.chat-form {
  padding: 1rem 1.5rem;
  border-top: var(--grid-line);
  background: rgba(250, 250, 248, 0.6);
  display: flex;
  gap: 0.75rem;
  align-items: flex-end;
}

.chat-form textarea {
  flex: 1;
  padding: 0.875rem 1.125rem;
  border: var(--grid-line);
  background: var(--off-white);
  font-size: 0.9375rem;
  font-family: inherit;
  color: var(--ink);
  resize: none;
  min-height: 2.75rem;
  max-height: 12rem;
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
}

.chat-form textarea::placeholder { color: var(--warm-grey-300); }

.chat-form textarea:focus {
  outline: none;
  border-color: var(--ink);
  box-shadow: 0 0 0 1px var(--ink);
}

.chat-form button {
  padding: 0.75rem 1.5rem;
  background: var(--ink);
  color: var(--off-white);
  font-size: 0.8125rem;
  font-weight: 500;
  border: var(--grid-line-strong);
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  transition: opacity var(--duration-fast), transform var(--duration-fast);
}

.chat-form button:hover:not(:disabled) {
  opacity: 0.9;
  transform: translateY(-1px);
}

.chat-form button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.chat-error {
  margin-top: 0.75rem;
  font-size: 0.875rem;
  color: #b91c1c;
}

/* --------------------------------------------------------------------------
   Projects – asymmetric grid, varying column widths
   -------------------------------------------------------------------------- */
.projects {
  padding: clamp(4rem, 10vw, 8rem) var(--grid-gap);
  border-bottom: var(--grid-line);
}

.projects-inner {
  max-width: 72rem;
  margin: 0 auto;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
}

/* Asymmetric cards – varied spans */
.project-card {
  grid-column: span 4;
  padding: 2rem;
  border: var(--grid-line);
  background: var(--off-white);
  transition: transform var(--duration-mid) var(--ease-out-expo),
              box-shadow var(--duration-mid),
              border-color var(--duration-fast);
  position: relative;
}

.project-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--ink);
  opacity: 0;
  transition: opacity var(--duration-mid) var(--ease-out-expo);
  pointer-events: none;
}

.project-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-subtle);
  border-color: var(--warm-grey-200);
}

.project-card:hover .project-card-content {
  color: var(--off-white);
}

.project-card:hover .project-card-content .project-year,
.project-card:hover .project-card-content .tags span {
  color: rgba(250, 250, 248, 0.8);
  border-color: rgba(250, 250, 248, 0.4);
}

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

.project-card-content {
  position: relative;
  z-index: 1;
  transition: color var(--duration-mid);
}

.project-card:nth-child(5n + 1) { grid-column: span 5; }
.project-card:nth-child(5n + 2) { grid-column: span 7; }
.project-card:nth-child(5n + 3) { grid-column: span 7; }
.project-card:nth-child(5n + 4) { grid-column: span 5; }
.project-card:nth-child(5n + 5) { grid-column: span 6; }
.project-card:nth-child(5n) { grid-column: span 6; }

.project-year {
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--warm-grey-300);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  display: block;
  margin-bottom: 0.75rem;
}

.project-card h3 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 0.75rem;
  letter-spacing: -0.01em;
}

.project-card p {
  font-size: 0.9375rem;
  color: var(--charcoal);
  line-height: 1.65;
  margin: 0 0 1.25rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tags span {
  padding: 0.25rem 0.5rem;
  border: var(--grid-line);
  background: transparent;
  color: var(--warm-grey-300);
  font-size: 0.6875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: color var(--duration-mid), border-color var(--duration-mid);
}

/* --------------------------------------------------------------------------
   Education
   -------------------------------------------------------------------------- */
.education {
  padding: clamp(4rem, 10vw, 8rem) var(--grid-gap);
}

.education-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
}

.edu-card {
  grid-column: span 6;
  padding: 2rem;
  border: var(--grid-line);
  background: var(--off-white);
  transition: border-color var(--duration-fast), transform var(--duration-mid);
}

.edu-card:hover {
  border-color: var(--warm-grey-200);
  transform: translateY(-2px);
}

.edu-card h3 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--ink);
  margin: 0 0 0.5rem;
}

.edu-degree { font-weight: 500; color: var(--ink); margin: 0 0 0.25rem; font-size: 0.9375rem; }
.edu-meta { font-size: 0.8125rem; color: var(--warm-grey-300); margin: 0 0 0.75rem; }
.edu-courses { font-size: 0.9375rem; color: var(--charcoal); line-height: 1.6; margin: 0; }

/* --------------------------------------------------------------------------
   Footer – minimal
   -------------------------------------------------------------------------- */
.footer {
  border-top: var(--grid-line);
  background: var(--cream);
  padding: 2rem var(--grid-gap);
  text-align: center;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--warm-grey-300);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.footer a {
  color: var(--charcoal);
  text-decoration: none;
  position: relative;
}

.footer a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 0;
  height: 1px;
  background: var(--charcoal);
  transition: width var(--duration-mid);
}

.footer a:hover::after { width: 100%; }

/* --------------------------------------------------------------------------
   Reveal animations – Intersection Observer targets
   -------------------------------------------------------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity var(--duration-slow) var(--ease-out-expo),
    transform var(--duration-slow) var(--ease-out-expo);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }
.reveal-delay-5 { transition-delay: 0.5s; }
.reveal-delay-6 { transition-delay: 0.6s; }

/* --------------------------------------------------------------------------
   Image containers – aspect ratios
   -------------------------------------------------------------------------- */
.img-container {
  aspect-ratio: 4 / 5;
  overflow: hidden;
  border: var(--grid-line);
}

.img-container--wide { aspect-ratio: 16 / 9; }

.img-container img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--duration-slow) var(--ease-out-expo);
}

.img-container:hover img { transform: scale(1.03); }


/* --------------------------------------------------------------------------
   Responsive – maintain grid on mobile
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .project-card,
  .project-card:nth-child(5n + 1),
  .project-card:nth-child(5n + 2),
  .project-card:nth-child(5n + 3),
  .project-card:nth-child(5n + 4),
  .project-card:nth-child(5n + 5),
  .project-card:nth-child(5n) {
    grid-column: span 12;
  }

  .edu-card { grid-column: span 12; }

  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    width: 100%;
    max-width: 280px;
    height: 100vh;
    background: var(--off-white);
    flex-direction: column;
    padding: 5rem 2rem 2rem;
    gap: 1.5rem;
    border-left: var(--grid-line);
    transform: translateX(100%);
    transition: transform var(--duration-mid) var(--ease-out-expo);
    z-index: 40;
  }

  .nav-links.is-open { transform: translateX(0); }

  .lang-toggle {
    margin-left: 0;
    padding-left: 0;
    padding-top: 0.5rem;
    border-left: none;
    border-top: var(--grid-line);
  }

  .nav-toggle { display: flex; }

  .hero-content { margin-left: 0; }

  .hero-img-container {
    display: none;
  }
}

@media (max-width: 600px) {
  :root {
    --grid-gap: 1rem;
  }

  .hero {
    min-height: 80vh;
    padding: 3rem var(--grid-gap) 4rem;
  }

  .project-card,
  .edu-card {
    padding: 1.5rem;
  }

  .section-desc { margin-bottom: 2rem; }
}