/* ============================================
   ASSM 2026 — Workshop Stylesheet
   Autonomous Systems for Sustainable Mobility
   ============================================ */

/* ===========================
   1. DESIGN TOKENS
   =========================== */
:root {
  --accent: #0c7c59;
  --accent2: #095e43;
  --accent-light: #0fa372;
  --bg: #ffffff;
  --bg-soft: #f4f8f6;
  --bg-dark: #eef3f0;
  --text: #1a2332;
  --text-sec: #475569;
  --text-muted: rgba(0,0,0,.55);
  --border: rgba(0,0,0,.07);
  --radius: 10px;
  --shadow: 0 10px 24px rgba(0,0,0,.06);
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --mono: 'JetBrains Mono', monospace;
}

/* ===========================
   2. BASE RESETS
   =========================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ===========================
   3. NAVBAR
   =========================== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
  height: 64px;
  display: flex; align-items: center;
}
.navbar .container {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 1100px; margin: 0 auto; width: 100%;
}
.nav-brand {
  font-weight: 700; font-size: 1.05rem; color: var(--text);
  text-decoration: none; display: flex; align-items: center; gap: .4rem;
}
.nav-brand span { color: var(--accent); }
.nav-links { display: flex; align-items: center; gap: .25rem; list-style: none; }
.nav-links a {
  color: var(--text-sec); text-decoration: none; font-size: .88rem;
  font-weight: 500; padding: .45rem .85rem; border-radius: 8px;
  transition: all .2s;
}
.nav-links a:not(.btn-accent):hover { color: var(--accent); background: rgba(12,124,89,.06); }
.nav-links .btn-accent { color: #fff; }
.nav-links .btn-accent:hover { color: #fff; background: var(--accent2); }

.mobile-toggle {
  display: none; background: none; border: 1px solid var(--border);
  padding: .35rem .5rem; border-radius: 6px; cursor: pointer; font-size: 1.2rem;
  color: var(--text);
}

/* ===========================
   4. BUTTONS
   =========================== */
.btn-accent {
  display: inline-flex; align-items: center; gap: .4rem;
  background: var(--accent); color: #fff; border: none;
  font-weight: 600; font-size: .85rem; padding: .5rem 1.1rem;
  border-radius: 8px; text-decoration: none; cursor: pointer;
  transition: all .2s; font-family: var(--font);
}
.btn-accent:hover {
  background: var(--accent2); transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(12,124,89,.25);
}

.btn-outline {
  display: inline-flex; align-items: center; gap: .4rem;
  background: transparent; color: var(--accent); border: 1.5px solid var(--accent);
  font-weight: 600; font-size: .85rem; padding: .5rem 1.1rem;
  border-radius: 8px; text-decoration: none; cursor: pointer;
  transition: all .2s; font-family: var(--font);
}
.btn-outline:hover { background: rgba(12,124,89,.06); }

/* ===========================
   5. HERO
   =========================== */
.hero {
  padding: 140px 1.5rem 72px;
  text-align: center;
  background:
    radial-gradient(ellipse 700px 500px at 20% 10%, rgba(12,124,89,.08), transparent),
    radial-gradient(ellipse 600px 400px at 80% 30%, rgba(15,163,114,.06), transparent),
    linear-gradient(180deg, #fff 0%, var(--bg-soft) 100%);
  border-bottom: 1px solid var(--border);
  position: relative;
}
.hero::after {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(12,124,89,.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(12,124,89,.02) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse at 50% 40%, black 20%, transparent 65%);
}
.hero .container { position: relative; z-index: 1; max-width: 820px; margin: 0 auto; }

.pill {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--mono); font-size: .72rem; font-weight: 500;
  letter-spacing: .06em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 1.5rem;
}
.pill i { font-size: .85rem; }

.badge-accent {
  display: inline-block; background: rgba(12,124,89,.1);
  border: 1px solid rgba(12,124,89,.2); border-radius: 999px;
  padding: .3rem .85rem; font-size: .78rem; font-weight: 500;
  color: var(--accent); margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.5rem);
  font-weight: 800; line-height: 1.18;
  letter-spacing: -.025em; margin-bottom: .75rem;
  color: var(--text);
}
.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero .subtitle {
  font-size: 1.05rem; color: var(--text-sec);
  max-width: 620px; margin: 0 auto 1.5rem; line-height: 1.6;
}

.hero-meta {
  display: flex; gap: 1.5rem; justify-content: center; flex-wrap: wrap;
  margin-bottom: 2rem; font-size: .88rem; color: var(--text-sec);
}
.hero-meta span { display: flex; align-items: center; gap: .35rem; }
.hero-meta i { color: var(--accent); font-size: 1rem; }

.hero-actions { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; }

/* ===========================
   6. SECTIONS
   =========================== */
.section { padding: 72px 1.5rem; }
.section .container { max-width: 1000px; margin: 0 auto; }
.section.bg-soft { background: var(--bg-soft); }
.section.bg-dark { background: var(--bg-dark); }
.anchor-offset { scroll-margin-top: 80px; }

.section-label {
  font-family: var(--mono); font-size: .72rem; font-weight: 500;
  letter-spacing: .1em; text-transform: uppercase;
  color: var(--accent); margin-bottom: .5rem;
}
.section-title {
  font-size: clamp(1.4rem, 3vw, 1.85rem);
  font-weight: 700; letter-spacing: -.02em;
  margin-bottom: .5rem; line-height: 1.2;
}
.section-desc {
  font-size: .95rem; color: var(--text-sec);
  max-width: 600px; margin-bottom: 2.5rem;
}

/* ===========================
   7. DATE CARDS
   =========================== */
.dates-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem; margin-bottom: 2rem;
}
.date-card {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.25rem;
  transition: all .25s; position: relative;
}
.date-card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.date-card.highlight {
  border-color: rgba(12,124,89,.25);
  background: linear-gradient(135deg, rgba(12,124,89,.03), rgba(15,163,114,.02));
}
.date-card .date-icon {
  width: 36px; height: 36px; border-radius: 8px;
  background: rgba(12,124,89,.08); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem; margin-bottom: .75rem;
}
.date-card .date-label {
  font-size: .8rem; color: var(--text-sec);
  margin-bottom: .25rem; font-weight: 500;
}
.date-card .date-value {
  font-weight: 700; font-size: .95rem; color: var(--text);
}

/* ===========================
   8. TOPICS
   =========================== */
.topics-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: .75rem;
}
.topic-item {
  display: flex; align-items: flex-start; gap: .75rem;
  padding: 1rem 1.15rem; background: var(--bg);
  border: 1px solid var(--border); border-radius: var(--radius);
  transition: all .25s;
}
.topic-item:hover { border-color: rgba(12,124,89,.2); box-shadow: var(--shadow); transform: translateY(-1px); }
.topic-icon {
  width: 32px; height: 32px; border-radius: 8px; flex-shrink: 0;
  background: rgba(12,124,89,.08); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: .9rem;
}
.topic-item h4 { font-size: .88rem; font-weight: 600; margin-bottom: .15rem; }
.topic-item p { font-size: .8rem; color: var(--text-sec); margin: 0; line-height: 1.45; }

/* ===========================
   9. PAPER CATEGORIES
   =========================== */
.papers-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
}
.paper-card {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.5rem;
  transition: all .25s; position: relative; overflow: hidden;
}
.paper-card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.paper-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0;
  height: 3px; background: linear-gradient(90deg, var(--accent), var(--accent-light));
}
.paper-card .paper-type {
  font-family: var(--mono); font-size: .7rem; font-weight: 500;
  letter-spacing: .08em; text-transform: uppercase;
  color: var(--accent); margin-bottom: .5rem;
}
.paper-card h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: .5rem; }
.paper-card p { font-size: .88rem; color: var(--text-sec); margin: 0; }
.paper-card .page-badge {
  display: inline-block; margin-top: .75rem; font-size: .78rem; font-weight: 600;
  background: rgba(12,124,89,.08); color: var(--accent);
  padding: .25rem .65rem; border-radius: 6px;
}

/* ===========================
   10. SUBMISSION INFO
   =========================== */
.submission-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 1.25rem; max-width: 750px;
}
.info-box {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.5rem;
  box-shadow: var(--shadow);
}
.info-row {
  display: flex; align-items: center; gap: .75rem;
  padding: .65rem 0; border-bottom: 1px solid var(--border);
}
.info-row:last-child { border-bottom: none; }
.info-row i { color: var(--accent); font-size: 1.1rem; flex-shrink: 0; }
.info-row .label { font-size: .82rem; color: var(--text-sec); min-width: 100px; }
.info-row .value { font-weight: 600; font-size: .9rem; }

.template-grid {
  display: flex; gap: .75rem; flex-wrap: wrap; margin-top: 2rem;
}

/* ===========================
   11. ORGANIZERS
   =========================== */
.org-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}
.org-card {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden;
  transition: all .25s;
}
.org-card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.org-card-body { padding: 1.5rem; }
.org-card h4 { font-size: 1rem; font-weight: 700; margin-bottom: .15rem; }
.org-role {
  font-size: .78rem; font-weight: 500; color: var(--accent);
  margin-bottom: .75rem; display: block;
}
.org-detail {
  display: flex; align-items: center; gap: .5rem;
  font-size: .82rem; color: var(--text-sec); margin-bottom: .4rem;
}
.org-detail i { color: var(--accent); font-size: .85rem; }
.org-detail a { color: var(--accent); text-decoration: none; }
.org-detail a:hover { text-decoration: underline; }

.org-bio {
  margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--border);
  font-size: .82rem; color: var(--text-sec); line-height: 1.6;
}

/* ===========================
   12. CALLOUT
   =========================== */
.callout {
  background: linear-gradient(135deg, rgba(12,124,89,.06), rgba(15,163,114,.03));
  border: 1px solid rgba(12,124,89,.15);
  border-radius: var(--radius); padding: 1.25rem 1.5rem;
  display: flex; align-items: flex-start; gap: .75rem;
  margin-top: 1.5rem;
}
.callout i { color: var(--accent); font-size: 1.15rem; margin-top: .1rem; flex-shrink: 0; }
.callout p { font-size: .88rem; color: var(--text-sec); margin: 0; }

/* ===========================
   13. CONTACT
   =========================== */
.contact-box {
  text-align: center; max-width: 550px; margin: 0 auto;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 2.5rem 2rem;
  box-shadow: var(--shadow);
}
.contact-icon {
  width: 52px; height: 52px; border-radius: 14px;
  background: rgba(12,124,89,.08); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; margin: 0 auto 1rem;
}
.contact-box h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: .5rem; }
.contact-box p { font-size: .9rem; color: var(--text-sec); margin-bottom: 1.25rem; }

/* ===========================
   14. FOOTER
   =========================== */
.footer {
  padding: 1.5rem; text-align: center;
  font-size: .82rem; color: var(--text-muted);
  border-top: 1px solid var(--border);
}
.footer a { color: var(--accent); text-decoration: none; }

/* ===========================
   15. RESPONSIVE
   =========================== */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-toggle { display: block; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 64px; left: 0; right: 0;
    background: rgba(255,255,255,.97); backdrop-filter: blur(14px);
    padding: 1rem; border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }
  .hero { padding: 120px 1rem 56px; }
  .hero h1 { font-size: 1.6rem; }
  .hero-meta { flex-direction: column; align-items: center; gap: .75rem; }
  .section { padding: 52px 1rem; }
  .dates-grid { grid-template-columns: 1fr 1fr; }
  .topics-grid { grid-template-columns: 1fr; }
  .submission-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .dates-grid { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .template-grid { flex-direction: column; }
}