/* Copyright (c) 2026 Mustafa Uzumeri. All rights reserved. */

/* ============================================
   EduOpsLab Design System
   ============================================ */

:root {
  /* Core palette — dark academic */
  --edu-midnight: #0b0b12;
  --edu-dark: #111620;
  --edu-panel: #131721;
  --edu-border: #1c2233;
  --edu-border-hover: rgba(99, 102, 241, 0.4);
  --edu-muted: #525e74;
  --edu-silver: #8892a8;
  --edu-cloud: #c0c8d8;
  --edu-text: #e4e4f0;
  --edu-white: #ffffff;

  /* Accents */
  --edu-indigo: #6366f1;
  --edu-indigo-light: #818cf8;
  --edu-indigo-glow: rgba(99, 102, 241, 0.15);
  --edu-teal: #10b981;
  --edu-teal-glow: rgba(16, 185, 129, 0.15);
  --edu-amber: #f97316;
  --edu-amber-glow: rgba(249, 115, 22, 0.15);

  /* Typography */
  --font-body: 'Inter', -apple-system, system-ui, sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Layout */
  --max-width: 900px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 150ms var(--ease-out);
  --transition-med: 300ms var(--ease-out);

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background: var(--edu-midnight);
  color: var(--edu-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--edu-white);
}

a {
  color: var(--edu-indigo-light);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--edu-white);
}

img {
  max-width: 100%;
  display: block;
}

/* --- Navigation --- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: var(--space-md) 0;
  background: rgba(11, 11, 18, 0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--edu-border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.nav__logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--edu-white);
}

.nav__logo span {
  color: var(--edu-indigo-light);
}

.nav__links {
  display: flex;
  gap: var(--space-lg);
  list-style: none;
}

.nav__link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--edu-silver);
  transition: color var(--transition-fast);
}

.nav__link:hover,
.nav__link--active {
  color: var(--edu-white);
}

/* Mobile nav */
@media (max-width: 640px) {
  .nav__links { gap: var(--space-md); }
  .nav__link { font-size: 0.8rem; }
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

/* --- Page Hero --- */
.page-hero {
  padding: var(--space-3xl) 0 var(--space-2xl);
  text-align: center;
  background: radial-gradient(ellipse at 50% 20%, var(--edu-indigo-glow) 0%, transparent 60%),
              radial-gradient(ellipse at 80% 80%, var(--edu-teal-glow) 0%, transparent 50%),
              var(--edu-midnight);
}

.page-hero h1 {
  font-size: clamp(1.8rem, 5vw, 2.6rem);
  margin-bottom: var(--space-sm);
}

.page-hero .tagline {
  color: var(--edu-silver);
  font-size: 1.05rem;
  line-height: 1.6;
  max-width: 600px;
  margin: 0 auto var(--space-sm);
}

.page-hero .subtitle {
  color: var(--edu-muted);
  font-size: 0.88rem;
}

/* --- Timeline --- */
.timeline {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  position: relative;
  margin: var(--space-2xl) 0;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--edu-border);
}

/* Era group */
.timeline__item {
  position: relative;
  background: var(--edu-panel);
  border: 1px solid var(--edu-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.timeline__item::before {
  content: '';
  position: absolute;
  left: calc(-2rem - 7px);
  top: 1.5rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--edu-muted);
  border: 2px solid var(--edu-midnight);
  z-index: 2;
}

/* Era colors */
.timeline__item--teaching         { border-left: 4px solid var(--edu-indigo); }
.timeline__item--teaching::before { background: var(--edu-indigo); }
.timeline__item--teaching .timeline__badge { background: var(--edu-indigo-glow); color: var(--edu-indigo-light); }

.timeline__item--elearning         { border-left: 4px solid var(--edu-teal); }
.timeline__item--elearning::before { background: var(--edu-teal); }
.timeline__item--elearning .timeline__badge { background: var(--edu-teal-glow); color: var(--edu-teal); }

.timeline__item--adv         { border-left: 4px solid var(--edu-amber); }
.timeline__item--adv::before { background: var(--edu-amber); }
.timeline__item--adv .timeline__badge { background: var(--edu-amber-glow); color: var(--edu-amber); }

/* Era header */
.timeline__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-md);
  gap: var(--space-md);
  flex-wrap: wrap;
}

.timeline__badge {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 100px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  display: inline-flex;
  align-items: center;
}

.timeline__date {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--edu-silver);
}

/* --- Expandable Entry Cards --- */
.timeline__entry {
  border: 1px solid var(--edu-border);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-sm);
  background: rgba(255, 255, 255, 0.02);
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.timeline__entry:last-child {
  margin-bottom: 0;
}

.timeline__entry:hover {
  border-color: rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.04);
}

.timeline__entry[open] {
  border-color: rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.03);
}

.timeline__entry-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.timeline__entry-header::-webkit-details-marker { display: none; }
.timeline__entry-header::marker { display: none; content: ''; }

.timeline__entry-year {
  font-size: 0.8125rem;
  font-weight: 700;
  min-width: 5.5em;
  flex-shrink: 0;
}

.timeline__item--teaching .timeline__entry-year  { color: var(--edu-indigo-light); }
.timeline__item--elearning .timeline__entry-year { color: var(--edu-teal); }
.timeline__item--adv .timeline__entry-year       { color: var(--edu-amber); }

.timeline__entry-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--edu-white);
  flex: 1;
}

.timeline__entry-chevron {
  font-size: 0.75rem;
  color: var(--edu-muted);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.timeline__entry[open] .timeline__entry-chevron {
  transform: rotate(90deg);
}

.timeline__entry-body {
  padding: 0 var(--space-lg) var(--space-lg);
  animation: entryReveal 300ms var(--ease-out);
}

@keyframes entryReveal {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.timeline__figure {
  margin-bottom: var(--space-md);
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--edu-border);
  background: var(--edu-white);
  padding: var(--space-sm);
}

.timeline__figure img {
  width: 100%;
  height: auto;
  max-height: 400px;
  object-fit: contain;
  display: block;
}

.timeline__entry-body p {
  font-size: 0.9375rem;
  color: var(--edu-silver);
  line-height: 1.8;
}

/* --- Section --- */
.section {
  padding: var(--space-3xl) 0;
}

.section__label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--edu-indigo-light);
  margin-bottom: var(--space-md);
}

.section__title {
  font-size: clamp(1.5rem, 4vw, 2.2rem);
  margin-bottom: var(--space-md);
}

.section__desc {
  font-size: 1rem;
  color: var(--edu-silver);
  max-width: 650px;
  line-height: 1.8;
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--edu-border);
  padding: var(--space-2xl) 0;
  text-align: center;
  color: var(--edu-muted);
  font-size: 0.82rem;
  line-height: 1.8;
}

.footer a {
  color: var(--edu-indigo-light);
}

/* --- Responsive --- */
@media (max-width: 640px) {
  .timeline__entry-header {
    flex-wrap: wrap;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
  }
  .timeline__entry-year { min-width: auto; }
  .timeline__figure img { max-height: 250px; }
}