/* ==========================================================================
   清水研究室 Webサイト — 共通スタイル
   Design concept: マイクロ波回路のスミスチャート(インピーダンス整合図)と
   方眼紙(高周波材料計測のグラフ用紙)をモチーフにした、静かで実務的な学術サイト。
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Shippori+Mincho:wght@400;500;600&family=Zen+Kaku+Gothic+New:wght@400;500;700&display=swap');

:root {
  /* Color: 方眼紙の紙色 / 酸化銅 / スミスチャートの罫線色 */
  --bg:        #f5f6f2;
  --bg-panel:  #ffffff;
  --ink:       #1c2430;
  --ink-soft:  #55606b;
  --copper:    #a3592e;
  --copper-deep: #7c4322;
  --teal:      #2e5b5e;
  --grid:      #d7dcd0;
  --grid-strong: #b9c2b2;
  --line-hair: 1px solid var(--grid);

  --serif: 'Shippori Mincho', 'Noto Serif JP', serif;
  --sans:  'Zen Kaku Gothic New', 'Noto Sans JP', sans-serif;

  --maxw: 960px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

/* 方眼紙グリッドを背景にうっすら敷く */
body {
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 28px 28px;
  background-position: -1px -1px;
  background-attachment: fixed;
}

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.4;
  margin: 0 0 0.6em;
  color: var(--ink);
}

h1 { font-size: 2.1rem; font-weight: 500; }
h2 { font-size: 1.5rem; border-bottom: var(--line-hair); padding-bottom: 0.5em; }
h3 { font-size: 1.15rem; color: var(--copper-deep); }

p { margin: 0 0 1.1em; max-width: 34em; }

a { color: var(--copper); text-decoration: none; border-bottom: 1px solid transparent; }
a:hover, a:focus-visible { border-bottom-color: currentColor; }
a:focus-visible { outline: 2px solid var(--teal); outline-offset: 2px; }

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header / Nav ---------- */
.site-header {
  background: var(--bg-panel);
  border-bottom: var(--line-hair);
}

.site-header .wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  padding-top: 22px;
  padding-bottom: 18px;
  gap: 12px 24px;
}

.brand {
  font-family: var(--serif);
  font-size: 1.15rem;
  color: var(--ink);
  letter-spacing: 0.02em;
}
.brand small {
  display: block;
  font-family: var(--sans);
  font-size: 0.72rem;
  color: var(--ink-soft);
  letter-spacing: 0.04em;
  margin-top: 2px;
}

/* Hamburger toggle (hidden on desktop) */
.nav-toggle {
  display: none;
  appearance: none;
  border: 1px solid var(--grid-strong);
  background: var(--bg-panel);
  width: 40px;
  height: 36px;
  position: relative;
  cursor: pointer;
  flex: 0 0 auto;
}
.nav-toggle span,
.nav-toggle::before,
.nav-toggle::after {
  content: "";
  position: absolute;
  left: 8px;
  right: 8px;
  height: 2px;
  background: var(--ink);
}
.nav-toggle::before { top: 11px; }
.nav-toggle span { top: 17px; }
.nav-toggle::after { top: 23px; }

nav.mainnav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 22px;
  font-size: 0.92rem;
}
nav.mainnav a {
  color: var(--ink-soft);
  border-bottom: none;
  padding: 4px 0;
  position: relative;
}
nav.mainnav a[aria-current="page"] {
  color: var(--copper-deep);
}
nav.mainnav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 2px;
  background: var(--copper);
}
nav.mainnav a:hover { color: var(--ink); }

.lang-switch {
  font-size: 0.82rem;
  color: var(--ink-soft);
}
.lang-switch a { color: var(--ink-soft); }
.lang-switch .current { color: var(--copper-deep); font-weight: 700; }

/* ---------- Hero ---------- */
.hero {
  padding: 64px 0 56px;
  border-bottom: var(--line-hair);
  background: var(--bg-panel);
  overflow: hidden;
}
.hero .wrap {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 36px;
  align-items: center;
}
.hero .eyebrow {
  font-size: 0.82rem;
  color: var(--teal);
  margin-bottom: 14px;
}
.hero h1 { font-size: 2.3rem; max-width: 13em; }
.hero .lede { color: var(--ink-soft); font-size: 1.02rem; }
.hero .smith {
  width: 100%;
  height: auto;
}

@media (max-width: 720px) {
  .hero .wrap { grid-template-columns: 1fr; }
  .hero .smith { max-width: 260px; margin: 0 auto; }
}

/* ---------- Sections / Cards ---------- */
main { padding: 52px 0 80px; }

.section { margin-bottom: 56px; }

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}
@media (max-width: 720px) {
  .grid-2 { grid-template-columns: 1fr; }
}

.card {
  background: var(--bg-panel);
  border: var(--line-hair);
  padding: 26px 28px;
}

.notice-list { list-style: none; margin: 0; padding: 0; }
.notice-list li {
  display: flex;
  gap: 18px;
  padding: 14px 0;
  border-bottom: var(--line-hair);
  align-items: baseline;
}
.notice-list li:first-child { border-top: var(--line-hair); }
.notice-list time {
  flex: 0 0 auto;
  font-variant-numeric: tabular-nums;
  color: var(--ink-soft);
  font-size: 0.86rem;
  min-width: 6.4em;
}

table.pub-list, table.member-list {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}
table.pub-list th, table.pub-list td,
table.member-list th, table.member-list td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: var(--line-hair);
  vertical-align: top;
}
table.pub-list th, table.member-list th {
  font-family: var(--serif);
  font-weight: 600;
  color: var(--ink-soft);
  font-size: 0.82rem;
  border-bottom: 1px solid var(--grid-strong);
}

ul.pub-items {
  list-style: none;
  margin: 0 0 8px;
  padding: 0;
}
ul.pub-items li {
  padding: 9px 0;
  border-bottom: var(--line-hair);
  font-size: 0.92rem;
  line-height: 1.65;
}
ul.pub-items li:first-child { border-top: var(--line-hair); }

.placeholder {
  color: var(--teal);
  background: #eef3ea;
  padding: 0 4px;
  border-radius: 2px;
  font-size: 0.92em;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  border: 1px solid var(--copper);
  color: var(--copper-deep);
  font-size: 0.92rem;
}
.btn:hover { background: var(--copper); color: #fff; border-bottom: 1px solid var(--copper); }

/* ---------- Figures / photos ---------- */
.figure {
  margin: 0;
  background: var(--bg-panel);
  border: var(--line-hair);
  padding: 14px;
}
.figure img {
  display: block;
  width: 100%;
  height: 180px;
  object-fit: contain;
  background: #f2f3ef;
}
.figure figcaption {
  margin-top: 10px;
  font-size: 0.82rem;
  color: var(--ink-soft);
  line-height: 1.5;
}
.figure-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 720px) {
  .figure-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .figure-grid { grid-template-columns: 1fr; }
}

/* ---------- Keyword chips ---------- */
.keywords {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 0;
  margin: 0;
}
.keywords li {
  border: 1px solid var(--teal);
  color: var(--teal);
  font-size: 0.85rem;
  padding: 4px 12px;
}

/* ---------- SDGs badges ---------- */
.sdg-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 14px;
}
.sdg-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid var(--grid-strong);
  padding: 3px 10px 3px 3px;
  font-size: 0.78rem;
  color: var(--ink-soft);
}
.sdg-badge .num {
  background: var(--ink);
  color: #fff;
  font-family: var(--serif);
  font-size: 0.78rem;
  width: 20px;
  height: 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ---------- Equipment list ---------- */
.equip-group { margin-bottom: 18px; }
.equip-group h4 {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--ink);
  margin: 0 0 6px;
}
.equip-group ul { margin: 0; padding-left: 1.2em; }
.equip-group li { margin-bottom: 3px; font-size: 0.94rem; }

/* ---------- People (members page) ---------- */
.person-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
@media (max-width: 640px) {
  .person-grid { grid-template-columns: 1fr; }
}
.person-card {
  background: var(--bg-panel);
  border: var(--line-hair);
  padding: 18px 20px;
}
.person-card .name-ja {
  font-family: var(--serif);
  font-size: 1.05rem;
  color: var(--ink);
}
.person-card .name-en {
  font-size: 0.82rem;
  color: var(--ink-soft);
  margin-bottom: 10px;
}
.person-card .grade {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.72rem;
  color: var(--copper);
  border: 1px solid var(--copper);
  padding: 1px 7px;
  margin-left: 8px;
  vertical-align: middle;
}
.person-card dl { margin: 10px 0 0; }
.person-card dt {
  font-size: 0.76rem;
  color: var(--teal);
  margin-top: 8px;
}
.person-card dd {
  margin: 2px 0 0;
  font-size: 0.9rem;
  line-height: 1.55;
}

/* ---------- Fit list (for-students) ---------- */
.fit-list { list-style: none; margin: 0; padding: 0; }
.fit-list li {
  display: flex;
  gap: 12px;
  padding: 10px 0;
  border-bottom: var(--line-hair);
}
.fit-list .mark {
  flex: 0 0 auto;
  font-family: var(--serif);
  color: var(--copper-deep);
  font-weight: 600;
  width: 1.4em;
}

/* ---------- Year schedule ---------- */
table.schedule { width: 100%; border-collapse: collapse; font-size: 0.94rem; }
table.schedule th, table.schedule td {
  text-align: left;
  padding: 8px 12px;
  border-bottom: var(--line-hair);
  vertical-align: top;
}
table.schedule th {
  font-family: var(--serif);
  font-weight: 600;
  color: var(--ink-soft);
  font-size: 0.82rem;
  width: 4.5em;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: var(--line-hair);
  padding: 32px 0;
  font-size: 0.85rem;
  color: var(--ink-soft);
}
.site-footer .wrap {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 24px;
}
.site-footer .fcol { display: flex; flex-direction: column; gap: 3px; }

/* ---------- Publications: collapsible per-year blocks ---------- */
details.pub-year {
  background: var(--bg-panel);
  border: var(--line-hair);
  padding: 2px 22px;
  margin-bottom: 12px;
}
details.pub-year summary {
  cursor: pointer;
  padding: 14px 0;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink);
  list-style: none;
  display: flex;
  align-items: baseline;
  gap: 10px;
}
details.pub-year summary::-webkit-details-marker { display: none; }
details.pub-year summary::before {
  content: "+";
  color: var(--copper);
  font-family: var(--sans);
  width: 1em;
}
details.pub-year[open] summary::before { content: "–"; }
.pub-count { font-family: var(--sans); font-weight: 400; font-size: 0.82rem; color: var(--ink-soft); }
.pub-subhead {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--teal);
  letter-spacing: 0.04em;
  margin: 4px 0 2px;
  padding-top: 10px;
  border-top: var(--line-hair);
}
details.pub-year ul.pub-items:first-of-type + .pub-subhead,
details.pub-year .pub-subhead:first-child { border-top: none; padding-top: 0; }
details.pub-year ol.pub-list { margin: 0 0 16px; padding-left: 1.3em; }
details.pub-year ol.pub-list li { font-size: 0.88rem; padding: 5px 0; border-bottom: var(--line-hair); line-height: 1.6; }
details.pub-year ol.pub-list li:last-child { border-bottom: none; }

/* ---------- Callout ---------- */
.callout {
  border: 1.5px solid var(--teal);
  background: #eef3ea;
  padding: 14px 18px;
  font-size: 0.92rem;
  color: var(--ink);
}

/* ---------- Activities (blog-post cards) ---------- */
.activity-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 720px) {
  .activity-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .activity-grid { grid-template-columns: 1fr; }
}
.activity-card {
  background: var(--bg-panel);
  border: var(--line-hair);
  display: flex;
  flex-direction: column;
}
.activity-card .activity-media {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: #f2f3ef;
  border-bottom: var(--line-hair);
  position: relative;
}
.activity-card .activity-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.activity-card .activity-placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--ink-soft);
  font-family: var(--serif);
  letter-spacing: 0.1em;
  font-size: 0.72rem;
}
.activity-card .activity-body {
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  flex: 1;
}
.activity-card .activity-date {
  margin: 0 0 6px;
  font-size: 0.8rem;
  color: var(--ink-soft);
  font-variant-numeric: tabular-nums;
}
.activity-card .activity-title {
  font-family: var(--serif);
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 8px;
  line-height: 1.55;
}
.activity-card .activity-summary {
  margin: 0 0 14px;
  font-size: 0.86rem;
  color: var(--ink-soft);
  line-height: 1.7;
}
.activity-card .activity-link {
  margin-top: auto;
  align-self: flex-start;
  font-size: 0.84rem;
  color: var(--copper-deep);
  border-bottom: 1px solid var(--copper);
}
.activity-status {
  padding: 22px;
  border: 1px dashed var(--grid-strong);
  background: var(--bg-panel);
  color: var(--ink-soft);
  text-align: center;
  font-size: 0.92rem;
}
.activity-more {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  align-items: center;
  margin-top: 20px;
}
.activity-more .source-note {
  color: var(--ink-soft);
  font-size: 0.8rem;
  margin-left: auto;
}

/* ---------- Utility ---------- */
.stack { display: flex; flex-direction: column; }
.stack > * + * { margin-top: 0.6em; }
.small { font-size: 0.86rem; color: var(--ink-soft); }

/* ==========================================================================
   Mobile optimization (<=720px)
   ========================================================================== */
@media (max-width: 720px) {
  body { font-size: 15.5px; }

  /* lighter, larger graph-paper grid so it reads as texture, not noise */
  body {
    background-size: 40px 40px;
  }

  /* header: brand subtitle hidden, hamburger shown, nav collapses */
  .site-header .wrap {
    padding-top: 14px;
    padding-bottom: 14px;
    align-items: center;
  }
  .brand { font-size: 1.05rem; }
  .brand small { display: none; }

  .nav-toggle { display: block; order: 2; }

  nav.mainnav {
    order: 3;
    flex-basis: 100%;
    max-height: 0;
    overflow: hidden;
    flex-direction: column;
    gap: 0;
    margin-top: 0;
    transition: max-height 0.2s ease;
  }
  nav.mainnav.is-open {
    max-height: 480px;
    margin-top: 12px;
    border-top: var(--line-hair);
  }
  nav.mainnav a {
    padding: 13px 4px;
    width: 100%;
    border-bottom: var(--line-hair);
  }
  nav.mainnav a[aria-current="page"]::after { display: none; }
  nav.mainnav a[aria-current="page"] { background: #f5f6f2; }

  /* hero */
  .hero { padding: 40px 0 32px; }
  .hero h1 { font-size: 1.7rem; }

  /* generous tap targets */
  .btn { padding: 12px 22px; }
  a { padding: 1px 0; }

  /* publications: keep pages from defaulting to a very long scroll */
  details.pub-year summary { padding: 16px 0; }
}