/* Base */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, "Helvetica Neue", Arial;
  line-height: 1.5;
}

body {
  color: #e5e7eb;
  overflow-x: hidden;
  background: #0b1220;
}

/* Background video + overlay */
#bg-video,
.video-overlay {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

#bg-video {
  z-index: -2;
  filter: saturate(1.0) contrast(1.0) brightness(0.95);
}

.video-overlay {
  z-index: -1;
  background:
    radial-gradient(900px 600px at 25% 10%, rgba(59, 130, 246, .10), transparent),
    radial-gradient(900px 600px at 90% 15%, rgba(34, 211, 238, .08), transparent),
    rgba(0, 0, 0, .34);
}

/* Welcome overlay */
.welcome {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: rgba(2, 6, 23, .62);
  opacity: 0;
  pointer-events: none;
  transition: opacity .7s ease;
  z-index: 20;
}

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

.welcome.hide {
  opacity: 0;
}

.welcome-inner {
  text-align: center;
  padding: 2rem 3rem;
  border: 1px solid rgba(148, 163, 184, .25);
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(255, 255, 255, .06), rgba(255, 255, 255, .03));
  box-shadow: 0 10px 30px rgba(0, 0, 0, .5);
}

.welcome h1 {
  margin: 0 0 .5rem;
  font-size: clamp(1.6rem, 4vw, 2.6rem);
  text-shadow: 0 0 18px rgba(34, 211, 238, .6);
}

.welcome p {
  margin: 0;
  color: #a5b4fc;
  opacity: .95;
}

/* Layout */
.container {
  width: min(100% - 2rem, 1100px);
  margin-inline: auto;
}

header.site-header {
  position: sticky;
  top: 0;
  background: rgba(17, 24, 39, .62);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(148, 163, 184, .2);
  z-index: 10;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.nav ul {
  list-style: none;
  display: flex;
  gap: 1rem;
  margin: 0;
  padding: 0;
}

.nav a {
  color: #e5e7eb;
  opacity: .92;
  padding: .5rem .75rem;
  border-radius: 10px;
  text-decoration: none;
}

.nav a:hover {
  background: rgba(148, 163, 184, .12);
}

.logo {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, #3b82f6, #22d3ee);
  display: inline-block;
}

.hero {
  padding: clamp(3rem, 6vw, 6rem) 0;
}

.hero-card {
  border: 1px solid rgba(148, 163, 184, .18);
  border-radius: 16px;
  padding: clamp(1.25rem, 2.5vw, 2rem);
  box-shadow: 0 10px 30px rgba(2, 6, 23, .5);
  background: rgba(255, 255, 255, .07);
}

.hero h1 {
  font-size: clamp(1.8rem, 3.8vw, 3rem);
  margin: 0 0 1rem;
}

.hero p {
  color: #c7d2fe;
  max-width: 60ch;
}

.cta {
  background: linear-gradient(135deg, #3b82f6, #22d3ee);
  color: white;
  padding: .75rem 1rem;
  border-radius: 999px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  display: inline-block;
  transition: transform .25s ease, box-shadow .25s ease;
  text-decoration: none;
}

.cta:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 8px 20px rgba(34, 211, 238, .25);
}

.features {
  padding: 2rem 0;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.card {
  background: rgba(255, 255, 255, .07);
  border: 1px solid rgba(148, 163, 184, .18);
  border-radius: 12px;
  padding: 1rem;
  transition: transform .4s ease, box-shadow .4s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, .25);
}

.grid-boxes-section {
  padding: 5rem 0;
  text-align: center;
}

.grid-title {
  font-size: 2rem;
  margin-bottom: 2rem;
  color: #22d3ee;
  text-shadow: 0 0 15px rgba(34, 211, 238, .4);
}

.boxes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  justify-items: center;
}

.box {
  width: 220px;
  height: 220px;
  border-radius: 16px;
  display: flex;
  justify-content: center;
  align-items: center;
  color: #e5e7eb;
  font-weight: 800;
  letter-spacing: .6px;
  text-transform: lowercase;
  background: rgba(255, 255, 255, 0.10);
  border: 1px solid rgba(59, 130, 246, 0.35);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: transform .3s ease, box-shadow .3s ease, background .3s ease;
  will-change: transform;
}

.box:hover {
  box-shadow: 0 0 28px rgba(59, 130, 246, .65), inset 0 0 22px rgba(34, 211, 238, .45);
  background: rgba(255, 255, 255, 0.14);
}

@media (max-width: 900px) {
  .boxes-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .boxes-grid {
    grid-template-columns: repeat(1, 1fr);
  }
}

footer {
  border-top: 1px solid rgba(148, 163, 184, .18);
  padding: 1.25rem 0;
  color: #cbd5e1;
  text-align: center;
}


/* BIT brand placeholder (logo will be replaced later) */
.bit-logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 64px;
  height: 32px;
  border-radius: 10px;
  font-weight: 900;
  letter-spacing: .18em;
  font-size: 14px;
  color: #e5e7eb;
  background: linear-gradient(135deg, rgba(59, 130, 246, .65), rgba(34, 211, 238, .55));
  border: 1px solid rgba(148, 163, 184, .25);
  box-shadow: 0 0 18px rgba(34, 211, 238, .18);
}

.brand {
  display: flex;
  gap: .75rem;
  align-items: center;
  text-decoration: none;
}

.muted {
  opacity: .75;
}

.lead {
  color: #c7d2fe;
  max-width: 70ch;
}


/* Nav tooltip (hover text for Services) */
.nav-tooltip {
  position: relative;
}

.nav-tooltip::after {
  content: attr(data-tooltip);
  position: absolute;
  left: 50%;
  top: calc(100% + 10px);
  transform: translateX(-50%);
  width: min(420px, 80vw);
  padding: 10px 12px;
  border-radius: 12px;
  background: rgba(2, 6, 23, 0.88);
  border: 1px solid rgba(148, 163, 184, .22);
  box-shadow: 0 12px 30px rgba(0, 0, 0, .45);
  color: #e5e7eb;
  font-size: 0.9rem;
  line-height: 1.35;
  opacity: 0;
  pointer-events: none;
  transition: opacity .18s ease, transform .18s ease;
  transform: translateX(-50%) translateY(-4px);
  z-index: 999;
  text-align: left;
  white-space: normal;
}

.nav-tooltip::before {
  content: "";
  position: absolute;
  left: 50%;
  top: calc(100% + 2px);
  transform: translateX(-50%);
  width: 0;
  height: 0;
  border-left: 7px solid transparent;
  border-right: 7px solid transparent;
  border-bottom: 8px solid rgba(2, 6, 23, 0.88);
  opacity: 0;
  transition: opacity .18s ease;
  pointer-events: none;
  z-index: 1000;
}

.nav-tooltip:hover::after,
.nav-tooltip:focus-visible::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.nav-tooltip:hover::before,
.nav-tooltip:focus-visible::before {
  opacity: 1;
}

/* Section headings */
.section-title {
  margin: 0 0 .5rem;
  font-size: 1.4rem;
  color: #e5e7eb;
  text-align: left;
}

.section-subtitle {
  margin: 0 0 1.25rem;
  color: #c7d2fe;
  text-align: left;
  max-width: 80ch;
}


/* Current nav item */
.nav a.current {
  background: rgba(148, 163, 184, .12);
  border: 1px solid rgba(34, 211, 238, .18);
}

/* Lists inside cards */
.card ul {
  margin: .75rem 0 0 1.2rem;
  padding: 0;
  color: #cbd5e1;
}

.card li {
  margin: .35rem 0;
}

.lead {
  font-size: 1.05rem;
}


/* Service card as button */
.service-link {
  text-decoration: none;
  color: inherit;
  display: block;
}

.service-link .card {
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease;
}

.service-link .card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: 0 12px 30px rgba(34, 211, 238, .35);
  background: rgba(255, 255, 255, .12);
}

.service-link .card h3 {
  color: #22d3ee;
}


/* Lecturer card emphasis */
.lecturer-card h3 {
  color: #22d3ee;
}

.lecturer-card ul {
  margin-top: .5rem;
}


/* Spacing between lecturer cards */
.lecturer-card+.lecturer-card {
  margin-top: 1.5rem;
}


/* Ensure lecturer cards align evenly */
.lecturer-card {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
}


/* Clickable service cards (keeps grid alignment) */
.clickable-card {
  cursor: pointer;
  user-select: none;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  min-height: 170px;
}

.clickable-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: 0 12px 30px rgba(34, 211, 238, .35);
  background: rgba(255, 255, 255, .12);
}

.clickable-card:focus-visible {
  outline: 2px solid rgba(34, 211, 238, .55);
  outline-offset: 4px;
}


/* Keep service tiles consistent height on home */
#services .grid .card.col-4 {
  min-height: 190px;
}


/* BIT main statement styling */
.bit-statement {
  font-size: clamp(1.35rem, 2.2vw, 1.9rem);
  line-height: 1.5;
  font-weight: 500;
  color: #7dd3fc;
  /* light blue */
  text-shadow: 0 0 18px rgba(56, 189, 248, 0.35);
  max-width: 48ch;
}


/* Unified BIT headline */
.bit-headline {
  font-size: clamp(1.6rem, 2.6vw, 2.2rem);
  line-height: 1.35;
  font-weight: 600;
  color: #7dd3fc;
  /* same light blue for BIT and text */
  text-shadow: 0 0 20px rgba(56, 189, 248, 0.4);
  max-width: 56ch;
}


/* Two-line BIT statement */
.bit-headline {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  line-height: 1.25;
  font-weight: 600;
  color: #7dd3fc;
  text-shadow: 0 0 18px rgba(56, 189, 248, 0.35);
  max-width: 60ch;
  margin-bottom: .6rem;
}

.bit-subline {
  font-size: clamp(1rem, 1.4vw, 1.2rem);
  line-height: 1.55;
  color: #f8fafc;
  max-width: 64ch;
}


.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(2, 6, 23, .35);
  backdrop-filter: blur(10px);
}


/* Section separation */
main>section.features {
  margin-top: 2.4rem;
  padding-top: 1.2rem;
}

.section-title {
  margin-top: 0;
}

.section-subtitle {
  margin-top: .35rem;
  margin-bottom: 1.25rem;
}

/* Vertical separator between products and projects */
.vertical-separator {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem 0;
  border-top: 1px solid rgba(148, 163, 184, .12);
  margin-top: 1rem;
}

.vertical-separator .section-title {
  font-size: 1.6rem;
  color: #22d3ee;
  text-shadow: 0 0 12px rgba(34, 211, 238, .25);
  margin-bottom: .25rem;
  text-align: center;
}

.projects-section {
  margin-top: 1.5rem;
  padding-top: .75rem;
}