/* ================================================
   Konstantinos Kourtzanidis — Personal Website
   Palette: Deep Indigo / Violet accent / Lavender
   Typefaces: Space Grotesk (display) + Inter (body)
   ================================================ */

:root {
  --navy:       #0D0820;
  --navy-light: #150D2E;
  --navy-mid:   #1E1240;
  --steel:      #9B8CC4;
  --steel-lt:   #C4B6E0;
  --off-white:  #F2EFF9;
  --white:      #FFFFFF;
  --cyan:       #C070FF;
  --cyan-dim:   rgba(176, 102, 255, 0.15);
  --cyan-dark:  #9944DD;

  --font-display: 'Space Grotesk', sans-serif;
  --font-body:    'Inter', sans-serif;

  --radius: 4px;
  --max-w: 1100px;
  --nav-h: 64px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--navy);
  color: var(--off-white);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ── UTILITIES ── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 32px;
}

.accent { color: var(--cyan); }
.accent-link { color: var(--cyan); text-decoration: none; }
.accent-link:hover { text-decoration: underline; }

.section-label {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 12px;
}

/* ── NAV ── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 40px;
  background: rgba(13, 8, 32, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(176, 102, 255, 0.10);
  z-index: 100;
}

.nav-logo {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 15px;
  color: var(--white);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 101;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--steel-lt);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-links {
  list-style: none;
  display: flex;
  gap: 32px;
}

.nav-links a {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 500;
  color: var(--steel);
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color 0.2s;
}

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

/* ── HERO ── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding-top: var(--nav-h);
  padding-left: 40px;
  padding-right: 40px;
}

.hero-bg-svg {
  position: absolute;
  right: -20px;
  top: 50%;
  transform: translateY(-50%);
  width: 65%;
  max-width: 900px;
  opacity: 0.8;
  pointer-events: none;
}

/* Bow shock pulse */
.shock-upper, .shock-main, .shock-lower {
  animation: shock-pulse 3.5s ease-in-out infinite alternate;
}
.shock-lower { animation-delay: 0.5s; }

.body-cone {
  animation: plasma-breathe 4s ease-in-out infinite alternate;
}
@keyframes shock-pulse {
  from { opacity: 0.35; }
  to   { opacity: 0.70; }
}

/* Plasma sheath halo breathe */
.plasma-pulse {
  animation: plasma-breathe 4s ease-in-out infinite alternate;
}
@keyframes plasma-breathe {
  from { opacity: 0.7; }
  to   { opacity: 1.0; }
}

/* Ablation glow flicker */
.abl-pulse {
  animation: abl-flicker 2.2s ease-in-out infinite alternate;
}
@keyframes abl-flicker {
  from { opacity: 0.75; }
  to   { opacity: 1.0; }
}

/* Plasma streamlets drift */
.plasma-streamlets {
  animation: streamlet-fade 3s ease-in-out infinite alternate;
}
@keyframes streamlet-fade {
  from { opacity: 0.25; }
  to   { opacity: 0.55; }
}

/* Spark particle twinkle */
.sparks {
  animation: spark-twinkle 2.8s ease-in-out infinite alternate;
}
.sparks-cyan {
  animation: spark-twinkle 2s ease-in-out infinite alternate;
  animation-delay: 0.5s;
}
@keyframes spark-twinkle {
  from { opacity: 0.6; }
  to   { opacity: 1.0; }
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 620px;
}

.hero-eyebrow {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
  margin-bottom: 20px;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(42px, 6vw, 72px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--white);
  margin-bottom: 16px;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(16px, 2.2vw, 22px);
  font-weight: 300;
  color: var(--steel-lt);
  line-height: 1.4;
  margin-bottom: 28px;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 36px;
}

.tag {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 5px 12px;
  border: 1px solid rgba(176, 102, 255, 0.35);
  border-radius: 2px;
  color: var(--cyan);
  background: var(--cyan-dim);
}

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

.btn-primary {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 12px 28px;
  background: var(--cyan);
  color: var(--navy);
  text-decoration: none;
  border-radius: var(--radius);
  transition: background 0.2s, transform 0.15s;
}

.btn-primary:hover {
  background: #D490FF;
  transform: translateY(-1px);
}

.btn-outline {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 12px 28px;
  border: 1px solid rgba(176, 102, 255, 0.5);
  color: var(--cyan);
  text-decoration: none;
  border-radius: var(--radius);
  transition: border-color 0.2s, background 0.2s;
}

.btn-outline:hover {
  border-color: var(--cyan);
  background: var(--cyan-dim);
}

/* ── SECTIONS ── */
.section { padding: 96px 0; }

.section-dark {
  background: var(--navy-light);
  padding: 96px 0;
}

/* ── ABOUT ── */
.two-col {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 80px;
  align-items: start;
}

.col-text h2 {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: 24px;
  color: var(--white);
}

.col-text p {
  color: var(--steel-lt);
  margin-bottom: 16px;
  font-size: 15px;
}

.affiliations {
  margin-top: 28px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.affil-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-size: 13px;
  color: var(--steel-lt);
}

.affil-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan);
  flex-shrink: 0;
}

.col-stat {
  display: flex;
  flex-direction: column;
  gap: 24px;
  padding-top: 8px;
}

.stat-block {
  border-left: 2px solid rgba(176, 102, 255, 0.28);
  padding-left: 20px;
}

.stat-num {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--white);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 12px;
  color: var(--steel);
  letter-spacing: 0.02em;
}

/* ── CARD GRID ── */
.section-dark h2 {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
  margin-bottom: 48px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.card {
  display: block;
  background: var(--navy-mid);
  border: 1px solid rgba(176, 102, 255, 0.10);
  border-radius: var(--radius);
  padding: 32px 28px;
  text-decoration: none;
  transition: border-color 0.2s, transform 0.15s, background 0.2s;
}

.card:hover {
  border-color: rgba(176, 102, 255, 0.40);
  transform: translateY(-3px);
  background: rgba(30, 18, 64, 0.9);
}

.card-icon { font-size: 28px; margin-bottom: 16px; line-height: 1; display: flex; align-items: center; }

.card h3 {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.card p {
  font-size: 13px;
  color: var(--steel);
  line-height: 1.65;
}

/* ── NEWS ── */
.section-news h2 {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
  margin-bottom: 48px;
}

.news-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-left: 1px solid rgba(176, 102, 255, 0.18);
  margin-left: 4px;
}

.news-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 24px;
  padding: 24px 0 24px 32px;
  border-bottom: 1px solid rgba(155, 140, 196, 0.1);
  position: relative;
}

.news-item::before {
  content: '';
  position: absolute;
  left: -4.5px;
  top: 32px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 8px rgba(176, 102, 255, 0.55);
}

.news-date {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--cyan);
  padding-top: 2px;
}

.news-body {
  font-size: 14px;
  color: var(--steel-lt);
  line-height: 1.65;
}

.news-body strong { color: var(--white); font-weight: 500; }

/* ── CONTACT ── */
.section-contact { background: var(--navy-light); }

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.section-contact h2 {
  font-family: var(--font-display);
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
  margin-bottom: 16px;
}

.section-contact p { color: var(--steel-lt); font-size: 15px; }

.contact-details {
  display: flex;
  flex-direction: column;
  gap: 28px;
  padding-top: 8px;
}

.contact-item { display: flex; flex-direction: column; gap: 4px; }

.contact-label {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
}

.contact-item span:last-child {
  font-size: 14px;
  color: var(--steel-lt);
  line-height: 1.6;
}

/* ── PAGE HEADER (inner pages) ── */
.page-header {
  padding: calc(var(--nav-h) + 64px) 40px 64px;
  background: var(--navy-light);
  border-bottom: 1px solid rgba(176, 102, 255, 0.10);
}

.page-header h1 {
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--white);
  max-width: var(--max-w);
  margin: 12px auto 0;
  padding: 0 32px;
}

.page-header .section-label {
  max-width: var(--max-w);
  margin: 0 auto 0;
  display: block;
  padding: 0 32px;
}

/* ── RESEARCH PAGE ── */
.research-block {
  padding: 64px 0;
  border-bottom: 1px solid rgba(155, 140, 196, 0.1);
}
.research-block:last-child { border-bottom: none; }

.research-block h2 {
  font-family: var(--font-display);
  font-size: clamp(20px, 2.5vw, 28px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--white);
  margin-bottom: 16px;
}

.research-block p {
  font-size: 15px;
  color: var(--steel-lt);
  margin-bottom: 14px;
  max-width: 760px;
}

.tech-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; }

.tech-tag {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.04em;
  padding: 4px 10px;
  border-radius: 2px;
  background: var(--navy-mid);
  color: var(--steel-lt);
  border: 1px solid rgba(155, 140, 196, 0.2);
}

/* ── PUBLICATIONS PAGE ── */
.pub-list { display: flex; flex-direction: column; gap: 0; }

.pub-item {
  padding: 28px 0;
  border-bottom: 1px solid rgba(155, 140, 196, 0.1);
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 24px;
  align-items: start;
}

.pub-year {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--cyan);
  padding-top: 3px;
}

.pub-details h3 {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 500;
  color: var(--white);
  margin-bottom: 6px;
  line-height: 1.4;
}

.pub-details .pub-authors { font-size: 13px; color: var(--steel); margin-bottom: 4px; }
.pub-details .pub-journal { font-size: 13px; color: var(--cyan); font-style: italic; }

.pub-section-head {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
  padding: 40px 0 12px;
  border-bottom: 1px solid rgba(176, 102, 255, 0.18);
  margin-bottom: 8px;
}

/* ── TEACHING PAGE ── */
.course-card {
  background: var(--navy-mid);
  border: 1px solid rgba(176, 102, 255, 0.10);
  border-radius: var(--radius);
  padding: 32px;
  margin-bottom: 20px;
}

.course-card h3 {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 8px;
}

.course-meta {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 14px;
}

.course-card p { font-size: 14px; color: var(--steel-lt); line-height: 1.7; }

/* ── FOOTER ── */
.footer {
  background: var(--navy);
  border-top: 1px solid rgba(155, 140, 196, 0.1);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-display);
  font-size: 12px;
  color: var(--steel);
  letter-spacing: 0.04em;
}

/* ── RESPONSIVE ── */
@media (max-width: 768px) {
  .nav { padding: 0 20px; }
  .nav-toggle { display: flex; }
  .nav-links {
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    background: rgba(13, 8, 32, 0.97);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(176, 102, 255, 0.12);
    transition: max-height 0.25s ease;
  }
  .nav-links.open { max-height: 320px; }
  .nav-links li { width: 100%; }
  .nav-links a {
    display: block;
    padding: 16px 20px;
    border-bottom: 1px solid rgba(155, 140, 196, 0.08);
  }
  .hero { padding-left: 20px; padding-right: 20px; }
  .hero-bg-svg { opacity: 0.25; width: 120%; }
  .two-col { grid-template-columns: 1fr; gap: 48px; }
  .contact-grid { grid-template-columns: 1fr; gap: 48px; }
  .pub-item { grid-template-columns: 1fr; gap: 4px; }
  .pub-year { padding-top: 0; }
  .footer-inner { flex-direction: column; gap: 8px; text-align: center; }
  .container { padding: 0 20px; }
  .page-header { padding: calc(var(--nav-h) + 40px) 20px 40px; }
  .page-header h1 { padding: 0; }
  .page-header .section-label { padding: 0; }
  .section, .section-dark, .section-news, .section-contact { padding: 64px 0; }
}

@media (prefers-reduced-motion: reduce) {
  .shock-upper, .shock-main, .plasma-pulse, .abl-pulse,
  .plasma-streamlets, .sparks, .sparks-cyan { animation: none; }
}