/* Rhine Robotics Paper Club — palette from the club's visual identity */
:root {
  --purple: #7A4E9D;
  --lilac: #C9B6E4;
  --green-dark: #1B4332;
  --green: #40916C;
  --cream: #EFE6DD;
  --sage: #C6D7C9;
  --paper: #F6F0EA;
  --rule: rgba(27, 67, 50, .28);
  --ink: var(--green-dark);
  --ink-soft: #3d5c4f;

  --serif: "Cormorant Garamond", "DejaVu Serif", Georgia, serif;
  --sans: "Source Sans 3", "DejaVu Sans", system-ui, sans-serif;
  --mono: "IBM Plex Mono", "DejaVu Sans Mono", ui-monospace, monospace;

  --wrap: 1120px;
  --gutter: clamp(16px, 4vw, 40px);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--cream);
  color: var(--ink);
  font: 400 1.0625rem/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--purple); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--green-dark); }
:focus-visible { outline: 2px solid var(--purple); outline-offset: 3px; }

h1, h2, h3, h4 { font-family: var(--serif); font-weight: 600; line-height: 1.1; margin: 0; }
h2 { font-size: clamp(2rem, 4.5vw, 2.9rem); margin-bottom: 1.25rem; }
h3 { font-size: 1.6rem; }
p { margin: 0 0 1rem; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.section { padding-block: clamp(56px, 9vw, 104px); border-top: 1px solid var(--rule); }

.label, .eyebrow {
  font: 500 .78rem/1.4 var(--sans);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--purple);
  margin-bottom: .75rem;
}
.eyebrow { color: var(--ink); margin: 0; }
.num { font: 400 .85rem var(--mono); color: var(--green); }
.prose p:last-child { margin-bottom: 0; }
.prose { max-width: 62ch; color: var(--ink-soft); font-size: 1.1rem; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: .4em;
  padding: .7em 1.25em;
  font: 600 .95rem/1 var(--sans);
  border-radius: 2px;
  text-decoration: none;
  border: 1px solid var(--green-dark);
  transition: background .15s, color .15s;
}
.btn--primary { background: var(--green-dark); color: var(--cream); }
.btn--primary:hover { background: var(--purple); border-color: var(--purple); color: #fff; }
.btn--ghost { background: transparent; color: var(--green-dark); }
.btn--ghost:hover { background: var(--green-dark); color: var(--cream); }

/* Top bar */
.topbar { border-bottom: 1px solid var(--green-dark); position: relative; z-index: 2; }
.topbar__inner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding-block: 18px; }
.topbar__nav { display: flex; gap: clamp(.9rem, 3vw, 2rem); flex-wrap: wrap; }
.topbar__nav a { color: var(--ink); text-decoration: none; font-size: .95rem; }
.topbar__nav a:hover { color: var(--purple); }

/* Hero */
.hero { position: relative; overflow: hidden; padding-block: clamp(48px, 8vw, 96px) clamp(64px, 10vw, 120px); }
.hero__art {
  position: absolute; inset: 0;
  background: url("../img/patent-bg.svg") right -60px top -40px / min(1100px, 120%) auto no-repeat;
  opacity: .12;
  pointer-events: none;
}
.hero__inner { position: relative; }
.hero__title { font-weight: 500; line-height: .9; letter-spacing: .01em; text-transform: uppercase; }
.hero__l1, .hero__l2 { display: block; font-size: clamp(3.4rem, 13vw, 9rem); }
.hero__l3 { display: block; font-size: clamp(2rem, 6.4vw, 4.6rem); color: var(--purple); letter-spacing: .06em; margin-top: .25em; }
.hero__tagline { font: italic 500 clamp(1.6rem, 3.6vw, 2.5rem)/1.2 var(--serif); margin: 1.6rem 0 1rem; }
.accent-rule { display: block; width: 64px; height: 3px; background: var(--purple); margin-bottom: 1.4rem; }
.hero__pitch { font-size: clamp(1.1rem, 2vw, 1.35rem); max-width: 34ch; }
.hero__ctas { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: 2rem; }

/* Intro */
.intro { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); gap: clamp(24px, 5vw, 64px); align-items: center; }
.intro > *, .discord > *, .meeting > * { min-width: 0; }
.intro__logo { width: 100%; -webkit-mask-image: radial-gradient(ellipse 70% 70% at center, #000 55%, transparent 100%); mask-image: radial-gradient(ellipse 70% 70% at center, #000 55%, transparent 100%); }

/* Discord panel */
.discord {
  display: grid; grid-template-columns: 1fr auto; gap: clamp(24px, 5vw, 56px); align-items: center;
  background: var(--sage);
  border-left: 8px solid var(--purple);
  padding: clamp(24px, 5vw, 48px);
  margin-bottom: clamp(56px, 9vw, 104px);
}
.discord h2 { margin-bottom: .75rem; }
.discord__qr { background: #fff; padding: 14px; display: block; }
.discord__qr img { width: clamp(140px, 18vw, 190px); height: auto; }
.ticks { list-style: none; padding: 0; margin: 0 0 1.5rem; }
.ticks li { padding-left: 1.6em; position: relative; margin-bottom: .35rem; }
.ticks li::before { content: "→"; position: absolute; left: 0; color: var(--purple); }

/* Meetings */
.group-heading { margin: 2.5rem 0 1.25rem; font-size: 1.5rem; display: flex; align-items: center; gap: 1rem; }
.group-heading::after { content: ""; flex: 1; height: 1px; background: var(--rule); }
.meetings { display: grid; gap: 1.5rem; }
.meeting {
  display: grid; grid-template-columns: 140px 1fr; gap: clamp(16px, 3vw, 40px);
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: clamp(20px, 3.5vw, 36px);
}
.meeting__date { display: flex; flex-direction: column; border-right: 1px solid var(--rule); padding-right: 1rem; }
.meeting__day { font: 500 4rem/1 var(--serif); }
.meeting__month { font: 500 .8rem var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--green); margin-top: .3rem; }
.meeting__weekday { font-size: .9rem; color: var(--ink-soft); }
.meeting__title { font-size: 1.9rem; margin-bottom: .5rem; }
.meeting__desc { color: var(--ink-soft); }
.meeting__facts { list-style: none; padding: 0; margin: .75rem 0 1.25rem; display: grid; gap: .3rem; }
.meeting__facts li { display: flex; gap: .75rem; }
.fact__key { font: 500 .78rem/1.9 var(--mono); text-transform: uppercase; letter-spacing: .08em; color: var(--green); min-width: 4.2em; }
.meeting__papers-heading { margin-top: 1rem; }
.papers { list-style: none; padding: 0; margin: 0 0 1.5rem; border-top: 1px solid var(--rule); }
.paper { display: grid; grid-template-columns: 2.2rem 1fr auto; gap: .75rem; align-items: baseline; padding: .9rem 0; border-bottom: 1px solid var(--rule); }
.paper__num { font: 400 .85rem var(--mono); color: var(--green); }
.paper__title { display: block; font: 600 1.3rem/1.25 var(--serif); color: var(--ink); text-decoration: none; }
a.paper__title:hover { color: var(--purple); text-decoration: underline; }
.paper__presenter { font-size: .95rem; color: var(--ink-soft); }
.paper__dl { font: 500 .8rem var(--mono); white-space: nowrap; text-decoration: none; border: 1px solid var(--purple); padding: .25em .6em; border-radius: 2px; }
.paper__dl:hover { background: var(--purple); color: #fff; }
.meeting__actions { display: flex; flex-wrap: wrap; gap: .75rem; }
.meetings--past .upcoming-only { display: none; }
.meetings--past .meeting { background: transparent; }
.empty { color: var(--ink-soft); font-style: italic; }

/* How it works */
.steps { list-style: none; padding: 0; margin: 1rem 0 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(20px, 4vw, 48px); }
.step { border-top: 3px solid var(--purple); padding-top: 1rem; }
.step h4 { font-size: 1.5rem; margin: .4rem 0 .5rem; }
.step p { color: var(--ink-soft); margin: 0; }

/* Topics */
.topics { list-style: none; padding: 0; margin: 1rem 0 2rem; display: grid; grid-template-columns: repeat(2, 1fr); grid-auto-flow: column; grid-template-rows: repeat(4, auto); column-gap: clamp(24px, 6vw, 80px); }
.topics li { font: 500 clamp(1.4rem, 2.6vw, 1.9rem)/1.2 var(--serif); padding: .7rem 0; border-bottom: 1px solid var(--rule); display: flex; gap: 1.1rem; align-items: baseline; }
.motto { font: 500 .78rem var(--sans); letter-spacing: .14em; text-transform: uppercase; color: var(--purple); margin: 0; }

/* About */
.about .prose { font-size: 1.2rem; }

/* Supporters */
.supporters { padding-block: 40px 56px; border-top: 1px solid var(--rule); }
.supporters__heading { margin-bottom: 1.25rem; }
.supporters__list { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; align-items: center; gap: clamp(24px, 5vw, 64px); }
.supporter { display: flex; align-items: center; gap: .8rem; color: #000; text-decoration: none; line-height: 1.25; }
.supporter img { height: 56px; width: auto; max-width: 280px; }
.supporters__list li:nth-child(2) .supporter img { height: 30px; }
.supporter__name { font-size: 1rem; }
a.supporter:hover { opacity: .75; color: #000; }

/* Footer */
.footer { background: var(--green-dark); color: var(--cream); font-size: .9rem; }
.footer__inner { display: flex; flex-wrap: wrap; gap: .5rem 2rem; padding-block: 24px; align-items: center; }
.footer a { color: var(--lilac); }
.footer__credit { margin-left: auto; opacity: .85; }

/* Responsive */
@media (max-width: 820px) {
  .topbar__right { display: none; }
  .intro, .discord { grid-template-columns: minmax(0, 1fr); }
  .intro__logo { max-width: 420px; }
  .discord__qr { justify-self: start; }
  .steps { grid-template-columns: 1fr; }
  .meeting { grid-template-columns: 1fr; }
  .meeting__date { flex-direction: row; align-items: baseline; gap: .75rem; border-right: 0; border-bottom: 1px solid var(--rule); padding: 0 0 .75rem; }
  .meeting__day { font-size: 2.6rem; }
  .footer__credit { margin-left: 0; }
}
@media (max-width: 560px) {
  .topbar__inner { flex-direction: column; align-items: flex-start; gap: .5rem; }
  .topics { grid-template-columns: 1fr; grid-auto-flow: row; grid-template-rows: none; }
  .paper { grid-template-columns: 1.8rem 1fr; }
  .paper__dl { grid-column: 2; justify-self: start; }
  .supporter img { height: 46px; }
}

/* Optional hero/topbar pieces (hidden when their text is empty in site.yml) */
.hero__title + .accent-rule { margin-top: 1.6rem; }
.topbar__nav:first-child { margin-inline: auto; }

/* Legal pages (Impressum, Datenschutz) */
.legal { max-width: calc(68ch + 2 * var(--gutter)); padding-block: clamp(40px, 7vw, 80px); }
.legal h1 { font-size: clamp(2.2rem, 5vw, 3.2rem); margin-bottom: 1.5rem; overflow-wrap: anywhere; hyphens: auto; }
.legal h2 { font-size: 1.5rem; margin: 2rem 0 .6rem; }
.legal p { color: var(--ink-soft); overflow-wrap: anywhere; }
.legal__lead { font-style: italic; }
.legal__date { margin-top: 2.5rem; font-size: .9rem; }