/* ===== Demo Banner ===== */
.demo-banner {
  background: #f59e0b;
  color: #1a1a1a;
  text-align: center;
  padding: .45rem 1rem;
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .04em;
  position: sticky;
  top: 0;
  z-index: 200;
}

/* ===== Base ===== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

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

:root {
  --ink:        #0f172a;
  --ink-mid:    #475569;
  --ink-light:  #94a3b8;
  --bg:         #f1f5f9;
  --bg-card:    #ffffff;
  --dark:       #0f172a;
  --accent:     #0ea5e9;      /* sky blue */
  --accent-dk:  #0284c7;
  --accent-lt:  #e0f2fe;
  --rule:       #e2e8f0;
  --nav-h:      60px;
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.75;
}

a { color: var(--accent-dk); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== Navigation ===== */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-card);
  height: var(--nav-h);
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--rule);
  box-shadow: 0 1px 8px rgba(0,0,0,.06);
}

.nav-inner {
  max-width: 1140px;
  width: 100%;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
}

.nav-logo {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: .06em;
  text-transform: uppercase;
  white-space: nowrap;
  margin-right: auto;
  padding-right: 2rem;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: .05rem;
}

.nav-links a {
  display: block;
  color: var(--ink-mid);
  padding: .4rem .7rem;
  font-size: .78rem;
  font-weight: 500;
  letter-spacing: .03em;
  text-transform: uppercase;
  transition: color .15s;
  border-radius: 4px;
}

.nav-links a:hover {
  color: var(--ink);
  background: var(--bg);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--accent-dk);
  font-weight: 700;
  text-decoration: none;
}

/* hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: .5rem;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--ink);
}

/* ===== Hero ===== */
.hero {
  position: relative;
  overflow: hidden;
  min-height: 540px;
  display: flex;
  align-items: center;
  background: var(--dark);
}

.hero-bg {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 55%;
  height: 100%;
  object-fit: cover;
  object-position: left center;
  z-index: 0;
  filter: brightness(.5) saturate(.7);
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    105deg,
    rgba(15,23,42,1)  0%,
    rgba(15,23,42,1)  40%,
    rgba(15,23,42,.7) 60%,
    rgba(15,23,42,.1) 100%
  );
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1140px;
  width: 100%;
  margin: 0 auto;
  padding: 5rem 2rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  background: var(--accent);
  color: #fff;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
  padding: .3rem .9rem;
  border-radius: 20px;
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: clamp(1.6rem, 3.5vw, 2.6rem);
  font-weight: 800;
  color: #fff;
  line-height: 1.2;
  max-width: 640px;
  margin-bottom: .5rem;
  letter-spacing: -.01em;
}

.hero h1 span {
  display: block;
  font-size: clamp(.82rem, 1.5vw, 1rem);
  color: rgba(255,255,255,.42);
  font-weight: 400;
  margin-top: .5rem;
  letter-spacing: .01em;
}

/* ===== Jointly Badge ===== */
.jointly-badge {
  display: inline-flex;
  align-items: center;
  margin: 1.25rem 0 2.2rem;
  padding: .45rem 1rem;
  background: rgba(14,165,233,.12);
  color: #7dd3fc;
  font-size: .82rem;
  font-weight: 500;
  border-radius: 4px;
  border: 1px solid rgba(14,165,233,.25);
}

.hero-info {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  max-width: 640px;
}

.hero-info-card {
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 8px;
  padding: .9rem 1.3rem;
  min-width: 200px;
  flex: 1;
  backdrop-filter: blur(8px);
}

.hero-info-card .label {
  font-size: .62rem;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: .3rem;
}

.hero-info-card .value {
  font-size: .88rem;
  font-weight: 600;
  color: #fff;
  line-height: 1.5;
}

.hero-info-card .value-ja {
  font-size: .77rem;
  color: rgba(255,255,255,.38);
  margin-top: .2rem;
}

/* ===== Page Container ===== */
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 3.5rem 2rem;
}

/* ===== Section Blocks ===== */
.section-block {
  background: var(--bg-card);
  border-radius: 10px;
  padding: 2.25rem 2.5rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,.06), 0 4px 16px rgba(0,0,0,.04);
}

.section-block p {
  margin-bottom: 1rem;
  color: var(--ink-mid);
  font-size: .95rem;
}

/* ===== Section Headings ===== */
h2.section-title {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--ink);
  margin-bottom: 1.4rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  display: flex;
  align-items: center;
  gap: .7rem;
}

h2.section-title::before {
  content: '';
  display: inline-block;
  width: 14px;
  height: 14px;
  background: var(--accent);
  border-radius: 3px;
  flex-shrink: 0;
}

h3.subsection-title {
  font-size: .88rem;
  font-weight: 700;
  color: var(--ink);
  margin: 1.75rem 0 .6rem;
  text-transform: uppercase;
  letter-spacing: .07em;
  padding-bottom: .4rem;
  border-bottom: 1px solid var(--rule);
}

/* ===== Tables ===== */
.dates-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .91rem;
}

.dates-table th {
  background: var(--bg);
  color: var(--ink-light);
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  padding: .6rem 1rem;
  text-align: left;
  border-bottom: 2px solid var(--rule);
}

.dates-table td {
  padding: .75rem 1rem;
  border-bottom: 1px solid var(--rule);
  color: var(--ink-mid);
}

.dates-table tbody tr:last-child td { border-bottom: none; }

.dates-table tbody tr:hover td {
  background: var(--accent-lt);
  color: var(--ink);
}

/* ===== Invited Speakers ===== */
.speakers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: .9rem;
}

.speaker-card {
  background: var(--bg);
  border-radius: 8px;
  padding: 1.1rem 1.2rem;
}

.speaker-card .name {
  font-weight: 700;
  font-size: .95rem;
  color: var(--ink);
}

.speaker-card .affil {
  font-size: .8rem;
  color: var(--ink-light);
  margin-top: .2rem;
}

/* ===== Organizers ===== */
.organizers-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(255px, 1fr));
  gap: .5rem;
}

.organizers-list li {
  font-size: .88rem;
  padding: .6rem .9rem;
  background: var(--bg);
  border-radius: 6px;
  color: var(--ink-mid);
}

/* ===== Sponsors ===== */
.sponsor-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
}

.sponsor-item {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  border-radius: 8px;
  padding: 1rem 1.5rem;
  transition: box-shadow .2s;
}

.sponsor-item:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,.1);
  text-decoration: none;
}

.sponsor-item img {
  height: auto;
  width: 180px;
  max-width: 100%;
  object-fit: contain;
  display: block;
}

/* ===== Alert / Announcement ===== */
.alert {
  padding: .85rem 1.1rem;
  margin-bottom: .6rem;
  background: var(--accent-lt);
  border-radius: 6px;
  font-size: .88rem;
  color: var(--ink-mid);
  border-left: 3px solid var(--accent);
}

/* ===== Button ===== */
.btn {
  display: inline-block;
  background: var(--accent);
  color: #fff !important;
  font-weight: 700;
  padding: .65rem 1.8rem;
  border-radius: 6px;
  font-size: .85rem;
  letter-spacing: .04em;
  text-transform: uppercase;
  transition: background .15s, box-shadow .15s;
  text-decoration: none !important;
  margin-top: .75rem;
}

.btn:hover {
  background: var(--accent-dk);
  box-shadow: 0 4px 16px rgba(14,165,233,.35);
}

/* ===== Page Hero (inner pages) ===== */
.page-hero {
  background: var(--dark);
  color: #fff;
  padding: 3rem 2rem;
  text-align: center;
}

.page-hero h1 {
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 800;
  letter-spacing: -.01em;
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}

.contact-card {
  background: var(--bg);
  border-radius: 8px;
  padding: 1.3rem 1.4rem;
}

.contact-card .role {
  font-size: .65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--accent-dk);
  margin-bottom: .4rem;
}

/* ===== Footer ===== */
footer {
  background: var(--dark);
  color: rgba(255,255,255,.38);
  text-align: center;
  padding: 2rem 1.5rem;
  font-size: .8rem;
  margin-top: 1.5rem;
}

footer a { color: rgba(255,255,255,.55); }
footer a:hover { color: #fff; text-decoration: none; }

/* ===== Responsive ===== */
@media (max-width: 700px) {
  .hero-bg { width: 100%; object-position: center; }
  .hero-content { padding: 3rem 1.5rem; }
  .nav-links {
    display: none;
    flex-direction: column;
    background: var(--bg-card);
    position: absolute;
    top: var(--nav-h);
    left: 0; right: 0;
    padding: .5rem 0;
    box-shadow: 0 4px 16px rgba(0,0,0,.08);
    border-top: 1px solid var(--rule);
  }
  .nav-links.open { display: flex; }
  .nav-links a { font-size: .85rem; padding: .6rem 1.5rem; }
  .nav-toggle { display: flex; }
  .nav-inner { position: relative; }
  .hero-info-card { min-width: 100%; }
  .container { padding: 2rem 1rem; }
  .section-block { padding: 1.5rem 1.25rem; margin-bottom: 1rem; }
}