@import url("https://fonts.googleapis.com/css2?family=Zen+Old+Mincho:wght@400;700;900&family=Zen+Maru+Gothic:wght@500&display=swap");

/* ==============================
   Reset
   ============================== */
*:where(:not(html, iframe, canvas, img, svg, video, audio):not(svg *, symbol *)) {
  all: unset;
  display: revert;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: none; text-size-adjust: none; }
a, button { cursor: revert; }
ol, ul, menu, summary { list-style: none; }
img { max-inline-size: 100%; max-block-size: 100%; }
table { border-collapse: collapse; }
input, textarea { -webkit-user-select: auto; }
textarea { white-space: revert; }
:where(pre) { all: revert; box-sizing: border-box; }
:where([hidden]) { display: none; }
* { margin: 0; }
body {
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  background: none;
}

body::before {
  content: "";
  position: fixed;
  top: var(--bg-top, -60px);
  left: 50%;
  transform: translateX(-50%);
  min-width: 1200px;
  width: 100%;
  height: 200vh;
  background: url('../img/bg.jpg') center top / cover no-repeat;
  filter: blur(var(--bg-blur, 2px));
  z-index: 0;
}

.site-content {
  max-width: 860px;
  margin: 0 auto;
  background: #fff;
  box-shadow: 0 0 40px rgba(0, 0, 0, 0.08);
  border-left: 1px solid var(--c-main);
  border-right: 1px solid var(--c-main);
}

@media (max-width: 600px) {
  .site-content {
    border-left: none;
    border-right: none;
  }
}
img, picture, video, canvas, svg { display: block; max-width: 100%; }
p, h1, h2, h3, h4, h5, h6 { overflow-wrap: break-word; }

/* ==============================
   Variables
   ============================== */
:root {
  --c-main: #00a6d2;
  --c-main-light: #e8f7fb;
  --c-main-pale: rgba(0, 167, 211, 0.15);
  --c-grey: #333333;
  --c-lightgrey: #f1f1f1;
  --c-w: #fff;
}

/* ==============================
   Base
   ============================== */
html {
  scroll-behavior: smooth;
  font-size: clamp(14px, 1.4705882353vw, 16px);
  font-family: "Zen Old Mincho", serif;
  font-weight: 700;
  font-optical-sizing: auto;
  color: var(--c-grey);
}

* {
  position: relative;
  z-index: 1;
  letter-spacing: 0.02em;
  line-height: 1.6em;
}

a[href] { transition: 0.2s; }
p { text-wrap: pretty; }
h1, h2, h3, h4, h5, h6 {
  text-wrap: balance;
  letter-spacing: 0.15em;
  font-weight: 700;
}

/* SP helpers */
br[sp][show] { display: none; }
@media (max-width: 600px) { br[sp][show] { display: block; } }
span[sp][show] { display: none; }
@media (max-width: 600px) { span[sp][show] { display: inline; } }
@media (max-width: 600px) { span[sp][hide] { display: none; } }

/* ==============================
   Typography
   ============================== */
.h1 { font-size: clamp(32px, 3.8vw, 48px); margin-bottom: clamp(20px, 3vw, 40px); }
.h2 { font-size: clamp(26px, 3vw, 36px); margin-bottom: clamp(20px, 3vw, 40px); }
.h3 { font-size: clamp(20px, 2.4vw, 28px); }
.h4 { font-size: clamp(16px, 1.76vw, 20px); }
.h5 { font-size: clamp(14px, 1.62vw, 18px); }
.h6 { font-size: clamp(14px, 1.47vw, 16px); }

.tc-main { color: var(--c-main); }
.tc-w { color: var(--c-w); }

/* ==============================
   Layout
   ============================== */
.innr3 { width: 100%; max-width: 767px; margin-inline: auto; padding: 0 3vw; }
.innr4 { width: 100%; max-width: 980px; margin-inline: auto; padding: 0 3vw; }
.innr5 { width: 100%; max-width: 1080px; margin-inline: auto; padding: 0 3vw; }

/* ==============================
   Header
   ============================== */
.hdr {
  width: 100%;
  background: transparent;
  min-height: clamp(60px, 7vw, 80px);
  padding-top: 8px;
  padding-bottom: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  top: 0;
  z-index: 100;
}

.hdr .innr5 {
  display: flex;
  justify-content: center;
  align-items: center;
  max-width: 800px;
  padding: 0;
  margin: 0 3vw;
}

.hdr__logo {
  margin-right: auto;
  font-size: clamp(9px, 2.5vw, 16px);
  font-weight: 400;
  color: var(--c-grey);
  letter-spacing: -0.02em;
  white-space: nowrap;
  text-decoration: none;
}

.hdr__nav {
  width: fit-content;
  margin-left: auto;
  padding-left: 3lvw;
}

.hdr__nav ul {
  margin: 0;
  padding: 0;
  width: 100%;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: clamp(12px, 1.76vw, 24px);
}

.hdr__nav ul li {
  display: flex;
  align-items: center;
  list-style: none;
  font-size: clamp(13px, 1.47vw, 16px);
  white-space: nowrap;
}

.hdr__nav ul li::before {
  content: "●";
  color: var(--c-main);
  width: 1.2em;
  font-size: 0.6em;
}

.hdr__nav ul li a {
  text-decoration: none;
  font-weight: 700;
  color: var(--c-grey);
}

.hdr__nav ul li a:hover {
  color: var(--c-main);
}

/* Hamburger */
.hamburger-menu {
  display: block;
  position: fixed;
  right: calc(50% - 400px + 1.5vw);
  top: clamp(12px, 1.5vw, 20px);
  z-index: 999;
}

@media (max-width: 860px) {
  .hamburger-menu {
    right: clamp(16px, 3vw, 30px);
  }
}
.hamburger-menu button {
  background: #fff;
  border: 1px solid var(--c-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  width: clamp(40px, 4vw, 50px);
  height: clamp(40px, 4vw, 50px);
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}
.hamburger-menu button span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--c-main);
  transition: 0.3s;
  transform-origin: center;
}

.hamburger-menu button.is-active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger-menu button.is-active span:nth-child(2) {
  opacity: 0;
}

.hamburger-menu button.is-active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}


.hdr__nav {
  display: none;
}

@media (max-width: 768px) {

  body {
    background-image: none;
    background-color: #f5f5f5;
  }

  body::before {
    display: none;
  }

  .hdr {
    padding-top: 10px;
  }
}

/* ==============================
   Hero
   ============================== */
.hero {
  padding: clamp(4px, 0.8vw, 10px) 3vw clamp(30px, 5vw, 60px);
  text-align: center;
}

.hero__frame {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  border-radius: 10px 10px 0 0;
  overflow: hidden;
}

.hero__img {
  width: 100%;
  height: auto;
  display: block;
}

.hero__wave {
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 100%;
  z-index: 3;
  line-height: 0;
}

.hero__wave svg {
  width: 100%;
  height: auto;
  display: block;
}

/* ==============================
   Main Title Section
   ============================== */
.main-title {
  text-align: center;
  padding: clamp(16px, 2.5vw, 32px) 3vw clamp(20px, 3vw, 40px);
}

.main-title__name {
  font-size: clamp(31px, 4.4vw, 53px);
  font-weight: 700;
  color: var(--c-main);
  letter-spacing: -0.06em;
  line-height: 1.1;
  margin-bottom: clamp(6px, 1vw, 12px);
  text-align: center;
}

.main-title__name small {
  display: block;
  font-size: inherit;
  margin-bottom: clamp(4px, 0.6vw, 8px);
}

.main-title__date {
  font-size: clamp(18px, 2.2vw, 26px);
  font-weight: 700;
  color: var(--c-main);
  margin-top: clamp(12px, 2vw, 24px);
  padding-top: clamp(12px, 2vw, 24px);
  display: inline-block;
  letter-spacing: 0.08em;
}

.main-title__date::before {
  content: "";
  display: block;
  width: 100%;
  height: 2px;
  background: var(--c-main);
  margin: 0 auto clamp(12px, 2vw, 24px);
}

.main-title__chair {
  font-size: clamp(14px, 1.6vw, 18px);
  color: var(--c-main);
  margin-top: clamp(6px, 1vw, 12px);
  letter-spacing: 0.06em;
}

/* ==============================
   Schedule Section
   ============================== */
.schedule {
  padding: 0 3vw clamp(40px, 6vw, 80px);
}

.schedule__inner {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.schedule__cosponsor {
  text-align: center;
  font-size: clamp(13px, 2vw, 22px);
  white-space: nowrap;
  color: var(--c-main);
  font-weight: 400;
  margin-top: clamp(12px, 1.5vw, 20px);
  letter-spacing: 0.06em;
}

.schedule__img {
  width: 100%;
  max-width: 720px;
  height: auto;
  display: inline-block;
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
}

/* ==============================
   Access Section
   ============================== */
.access {
  padding: clamp(30px, 5vw, 60px) 3vw;
}

.access__title::before {
  content: "";
  display: block;
  width: 300px;
  height: 1px;
  background: var(--c-main);
  margin: 0 auto clamp(30px, 4vw, 50px);
}

.access__title {
  text-align: center;
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 700;
  color: var(--c-main);
  margin-bottom: clamp(24px, 4vw, 48px);
  letter-spacing: 0.12em;
}

.access__grid {
  display: flex;
  flex-direction: column;
  gap: clamp(30px, 5vw, 60px);
  max-width: 720px;
  margin: 0 auto;
  border: 1px solid var(--c-main);
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
  padding: clamp(48px, 8vw, 80px) clamp(24px, 4vw, 40px);
}

.access__item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.access__map-embed {
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  margin-top: clamp(10px, 1.5vw, 20px);
  border: 1px solid var(--c-main);
}

.access__map-embed iframe {
  width: 100%;
  height: 300px;
  border: 0;
  display: block;
}

.access__info {
  font-size: clamp(14px, 1.5vw, 18px);
  line-height: 1.7;
  color: var(--c-grey);
}

.access__address {
  display: block;
  font-size: clamp(13px, 1.3vw, 15px);
  color: #666;
  font-weight: 400;
  margin-top: 4px;
}

.access__info strong {
  font-weight: 700;
  font-size: clamp(18px, 2vw, 24px);
  display: block;
  margin-bottom: 4px;
}

/* ==============================
   Greeting Section
   ============================== */
.greeting {
  padding: clamp(40px, 6vw, 80px) 3vw;
}

.greeting__inner {
  max-width: 720px;
  margin: 0 auto;
}

.greeting__title::before {
  content: "";
  display: block;
  width: 300px;
  height: 1px;
  background: var(--c-main);
  margin: 0 auto clamp(30px, 4vw, 50px);
}

.greeting__title {
  text-align: center;
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 700;
  color: var(--c-main);
  letter-spacing: 0.12em;
  margin-bottom: clamp(24px, 4vw, 48px);
}

.greeting__body {
  font-size: clamp(17px, 1.6vw, 18px);
  line-height: 1.8;
  letter-spacing: -0.02em !important;
  color: var(--c-grey);
  font-weight: 400;
  text-align: justify;
  text-justify: inter-character;
  border: 1px solid var(--c-main);
  border-radius: 10px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
  padding: clamp(48px, 8vw, 80px) clamp(24px, 4vw, 40px);
}

@media (max-width: 600px) {
  .greeting__body {
    line-height: 1.6 !important;
    letter-spacing: -0.04em !important;
  }
}

.greeting__body p {
  margin-bottom: 1.5em;
}

.greeting__body p:last-child {
  margin-bottom: 0;
}

.greeting__name {
  font-size: 1.5em;
  line-height: 1.2;
}

.greeting__sign {
  text-align: right;
  font-size: clamp(14px, 1.47vw, 16px);
  color: var(--c-main);
  font-weight: 700;
  line-height: 1.3;
  margin-top: clamp(30px, 5vw, 60px);
}

/* ==============================
   PDF Button
   ============================== */
.pdf-section {
  text-align: center;
  padding: clamp(20px, 4vw, 50px) 3vw clamp(30px, 5vw, 60px);
}

.btn-pdf {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  text-decoration: none;
  color: var(--c-main);
  background-color: transparent;
  padding: clamp(10px, 1.4vw, 16px) clamp(30px, 4vw, 60px);
  border-radius: 1000px;
  font-size: clamp(15px, 1.76vw, 20px);
  font-weight: 700;
  letter-spacing: 0.08em;
  border: 2px solid var(--c-main);
  transition: 0.3s;
  cursor: pointer;
}

.btn-pdf:hover {
  background-color: var(--c-main);
  color: var(--c-w);
}

/* ==============================
   Footer
   ============================== */
.ft {
  background: #333;
  padding: clamp(8px, 1vw, 12px) 3vw;
  text-align: center;
}

.ft__text {
  color: #fff;
  font-size: clamp(10px, 1.1vw, 12px);
  letter-spacing: 0.06em;
  font-weight: 400;
}

/* ==============================
   Back to Top
   ============================== */
.back-to-top {
  position: fixed;
  bottom: -160px;
  right: calc(50% - 400px + 1.5vw);
  width: clamp(36px, 4.4vw, 56px);
  aspect-ratio: 1 / 1;
  background-color: var(--c-main);
  border-radius: 50%;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, bottom 0.3s, transform 0.3s;
  z-index: 1000;
}

.back-to-top img {
  width: clamp(36px, 4.4vw, 56px);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(-20px);
  bottom: 0;
}

/* ==============================
   Utilities
   ============================== */
.text-center { text-align: center; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ==============================
   Animations
   ============================== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.hero__frame {
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeIn 1.2s ease 0.3s forwards;
}

@keyframes heroFadeIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes sideMessageFadeIn {
  from {
    opacity: 0;
    transform: translateX(-50%) translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
}

.hero-fade {
  opacity: 0;
  transform: translateY(20px);
  animation: heroFadeIn 1.2s ease 0.6s forwards;
}

/* ==============================
   Side Message (PC)
   ============================== */
.side-message {
  position: fixed;
  left: calc((50% - 430px) / 2);
  transform: translateX(-50%);
  opacity: 0;
  animation: sideMessageFadeIn 1.2s ease 0.8s forwards;
  top: clamp(60px, 8vw, 100px);
  writing-mode: vertical-rl;
  color: #fff;
  font-size: 18px;
  font-weight: 400;
  letter-spacing: 0.15em;
  z-index: 100;
}

@media (max-width: 1100px) {
  .side-message {
    display: none;
  }
}

/* ==============================
   Side Nav (PC)
   ============================== */
.side-nav {
  position: fixed;
  left: calc(50% + 430px + 20px);
  top: clamp(60px, 8vw, 100px);
  opacity: 0;
  animation: heroFadeIn 1.2s ease 0.8s forwards;
  z-index: 100;
}

.side-nav__label {
  font-size: clamp(12px, 1.2vw, 14px);
  font-weight: 700;
  color: rgba(255, 255, 255, 0.6);
  letter-spacing: 0.15em;
  margin-bottom: clamp(12px, 1.5vw, 20px);
}

.side-nav ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 22px;
}

@media (max-width: 768px) {
  .side-nav ul {
    gap: 24px;
  }
}

.side-nav ul li a {
  text-decoration: none;
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.1em;
  transition: 0.3s;
  display: inline-block;
  padding-bottom: 4px;
  position: relative;
}

.side-nav ul li a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 1.5em;
  height: 1px;
  background: #fff;
  transition: width 0.3s ease;
}

.side-nav ul li a:hover::after {
  width: 9em;
}

/* Menu Overlay */
.menu-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, rgba(0, 130, 170, 0.92) 0%, rgba(21, 203, 255, 0.85) 50%, rgba(180, 235, 255, 0.88) 100%);
  z-index: 140;
  opacity: 0;
  visibility: hidden;
  backdrop-filter: blur(0px);
  -webkit-backdrop-filter: blur(0px);
  transition: opacity 0.4s ease, visibility 0.4s ease, backdrop-filter 0.8s ease, -webkit-backdrop-filter 0.8s ease;
}


.menu-overlay.active {
  opacity: 1;
  visibility: visible;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

/* Side nav open state */
.side-nav {
  transition: left 0.4s ease, transform 0.4s ease;
}

.side-nav.is-open {
  left: 50% !important;
  transform: translateX(-50%) !important;
  z-index: 150;
}

.side-nav__momo {
  width: 120px;
  height: auto;
  margin-top: clamp(48px, 5vw, 56px);
  opacity: 0.7;
}

@media (max-width: 1100px) {
  .side-nav:not(.is-open) {
    display: none;
  }
  .side-nav {
    animation: none !important;
    opacity: 1 !important;
  }
  .side-nav ul li a {
    font-size: 22px;
  }
}

/* TOC offset */
[id*="toc-"] {
  scroll-margin-top: 80px;
}