/* style.css — layout & components
   iYouth 公共事務領袖培訓計劃 (redesign prototype) */

/* =============== HEADER =============== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in oklab, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(14px) saturate(1.1);
  border-bottom: 1px solid transparent;
  transition:
    transform 400ms cubic-bezier(0.16, 1, 0.3, 1),
    border-color 300ms ease,
    background-color 300ms ease;
}
.site-header.is-scrolled {
  border-bottom-color: var(--color-border);
}
.site-header.is-hidden {
  transform: translateY(-100%);
}

.site-header__inner {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: var(--space-3) var(--gutter);
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  gap: clamp(var(--space-2), 2vw, var(--space-6));
}

/* Co-brand lockup: official Youth Council logo (left) + the iYouth programme name
   (right). One flex group, one hit area, one visual unit. */
.brand {
  display: inline-flex;
  align-items: center;
  gap: clamp(0.5rem, 1.2vw, var(--space-4));
  color: var(--color-text);
  min-height: 44px;
  min-width: 0;
}
.brand__text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  line-height: 1.15;
  min-width: 0;
}
.brand__name {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}
.brand__sub {
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  white-space: nowrap;
}
@media (max-width: 860px) {
  .brand__name {
    font-size: 1rem;
  }
  .brand__sub {
    font-size: 0.6875rem;
    letter-spacing: 0.04em;
  }
}
@media (max-width: 380px) {
  .brand__name {
    font-size: 0.9375rem;
  }
  .brand__sub {
    font-size: 0.625rem;
    letter-spacing: 0.01em;
  }
}
.brand__mark {
  color: var(--color-text);
  flex: none;
}
.nav {
  margin-inline-start: auto;
}
.nav__list {
  display: flex;
  align-items: center;
  gap: clamp(var(--space-4), 2vw, var(--space-8));
  list-style: none;
}
.nav__list a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  position: relative;
}
.nav__list a::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 10px;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-interactive);
}
.nav__list a:hover,
.nav__list a[aria-current='true'] {
  color: var(--color-text);
}
.nav__list a:hover::after,
.nav__list a[aria-current='true']::after {
  transform: scaleX(1);
  background: var(--color-accent-ui);
  height: 2px;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.nav-toggle {
  display: none;
}

@media (max-width: 860px) {
  .nav {
    display: none;
  }
  .nav-toggle {
    display: inline-flex;
  }
  .site-header__cta {
    display: none;
  }
  .site-header__actions {
    margin-inline-start: auto;
  }
}

/* Mobile nav */
.mobile-nav {
  border-top: 1px solid var(--color-border);
  padding: var(--space-4) var(--gutter) var(--space-8);
  background: var(--color-bg);
}
.mobile-nav[hidden] {
  display: none;
}
.mobile-nav__list {
  list-style: none;
  margin-bottom: var(--space-6);
}
.mobile-nav__list a {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: 52px;
  padding-block: var(--space-2);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-serif);
  font-size: var(--text-lg);
}
.mobile-nav__list a span {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-faint);
}

/* =============== SECTION SHELL =============== */
.section {
  padding-block: clamp(var(--space-16), 11vw, var(--space-32));
}
.section-head {
  max-width: var(--content-default);
  margin-bottom: clamp(var(--space-10), 6vw, var(--space-20));
}
.section-head--split {
  max-width: none;
  display: grid;
  gap: var(--space-6);
  align-items: end;
}
@media (min-width: 900px) {
  .section-head--split {
    grid-template-columns: 1.15fr 1fr;
    gap: var(--space-16);
  }
}
.section-title {
  font-family: var(--font-serif);
  font-size: var(--text-xl);
  font-weight: 600;
  margin-top: var(--space-4);
  max-width: 30ch;
}
.section-title--light {
  color: var(--color-on-dark);
}
.section-lede {
  margin-top: var(--space-5);
  max-width: 46ch;
  color: var(--color-text-muted);
}

.pull-quote {
  margin-block: clamp(var(--space-10), 6vw, var(--space-16));
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 500;
  line-height: 1.55;
  color: var(--color-text);
  border-left: 1px solid var(--color-green);
  padding-left: clamp(var(--space-4), 3vw, var(--space-8));
}
.pull-quote--light {
  color: var(--color-on-dark);
  border-left-color: var(--color-lime);
}

/* =============== HERO =============== */
.hero {
  background: var(--color-forest);
  color: var(--color-on-dark);
  /* Safe top padding: always clears the sticky header height even on short
     viewports (600-720px tall laptops), so the h1 can never be clipped. */
  padding-top: max(calc(var(--header-h) + var(--space-6)), clamp(var(--space-12), 9vh, var(--space-24)));
  padding-bottom: clamp(var(--space-12), 9vh, var(--space-24));
  position: relative;
}
.hero--video {
  padding-bottom: 0;
}
.hero::after {
  content: '';
  position: absolute;
  inset-inline: 0;
  bottom: 0;
  height: 1px;
  background: var(--color-forest-deep);
}
.hero__inner {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.hero__title {
  font-family: var(--font-serif);
  font-size: var(--text-3xl);
  font-weight: 600;
  line-height: 1.22;
  letter-spacing: 0.005em;
  margin-top: var(--space-6);
  max-width: 22ch;
}
.hero__lede {
  margin-top: var(--space-8);
  max-width: 40ch;
  font-size: var(--text-lg);
  font-weight: 300;
  line-height: 1.85;
  color: var(--color-on-dark-muted);
}
.hero__actions {
  margin-top: clamp(var(--space-8), 4vw, var(--space-12));
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4) var(--space-8);
}

/* =============== ABOUT / 理念 =============== */
.section--about {
  background: var(--color-bg);
}
.manifesto {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: grid;
  gap: clamp(var(--space-10), 6vw, var(--space-20));
}
@media (min-width: 960px) {
  .manifesto {
    grid-template-columns: minmax(15rem, 22rem) minmax(0, 1fr);
  }
  .manifesto__aside {
    position: sticky;
    top: calc(var(--header-h) + var(--space-10));
    align-self: start;
  }
}
.manifesto__title {
  font-family: var(--font-serif);
  font-size: var(--text-2xl);
  font-weight: 600;
  line-height: 1.12;
  margin-top: var(--space-5);
}
.manifesto__note {
  margin-top: var(--space-6);
  max-width: 24ch;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-hairline);
  padding-top: var(--space-4);
}

/* Three parallel rows on one grid: the index, term and body columns start at the
   same x on every row (no stagger, no per-item offsets or widths). */
.passages {
  display: grid;
  gap: clamp(var(--space-8), 4vw, var(--space-12));
}
.passage {
  display: grid;
  grid-template-columns: 3.5rem minmax(0, 1fr);
  column-gap: var(--space-4);
  row-gap: 0;
  align-items: start;
  max-width: none;
}
@media (min-width: 760px) {
  .passage {
    grid-template-columns: 6rem minmax(0, 1fr);
    column-gap: var(--space-10);
  }
}
.passage__index {
  grid-column: 1;
  grid-row: 1;
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--color-green-text);
  font-variant-numeric: tabular-nums lining-nums;
  padding-top: 0.35em;
}
.passage__term,
.passage p:not(.passage__index) {
  grid-column: 2;
}
.passage__term {
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 600;
  margin-block: 0 var(--space-4);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-3);
}
.passage__en {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-text-faint);
}
.passage p:not(.passage__index) {
  color: var(--color-text-muted);
  max-width: 52ch;
}

/* =============== PROGRAMME =============== */
.section--programme {
  background: var(--color-surface);
  border-block: 1px solid var(--color-border);
}
.journey {
  list-style: none;
  border-top: 1px solid var(--color-hairline);
}
.journey__step {
  display: grid;
  grid-template-columns: 3.5rem minmax(0, 1fr);
  gap: var(--space-4);
  padding-block: clamp(var(--space-8), 4vw, var(--space-12));
  border-bottom: 1px solid var(--color-border);
}
@media (min-width: 760px) {
  .journey__step {
    grid-template-columns: 6rem minmax(0, 1fr);
    gap: var(--space-10);
  }
}
.journey__num {
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--color-text-faint);
  font-variant-numeric: tabular-nums lining-nums;
  padding-top: 0.35em;
}
.journey__term {
  font-family: var(--font-serif);
  font-size: var(--text-xl);
  font-weight: 600;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-4);
}
.journey__en {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-green-text);
}
.journey__body p {
  margin-top: var(--space-4);
  max-width: 50ch;
  color: var(--color-text-muted);
}
.tags {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-5);
  margin-top: var(--space-5);
}
.tags li {
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-text-faint);
  border-bottom: 1px solid var(--color-hairline);
  padding-bottom: 2px;
}

/* =============== TRAINING CAMP (dark band) =============== */
.section--camp {
  background: var(--color-forest-deep);
  color: var(--color-on-dark);
}
.camp {
  display: grid;
  gap: clamp(var(--space-12), 7vw, var(--space-24));
}
@media (min-width: 960px) {
  .camp {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: clamp(var(--space-12), 8vw, var(--space-32));
  }
}
.camp__lead p {
  margin-top: var(--space-6);
  max-width: 44ch;
  color: var(--color-on-dark-muted);
}
.camp__lead .section-title {
  margin-top: var(--space-5);
}

.process {
  list-style: none;
  counter-reset: step;
  align-self: center;
}
.process li {
  counter-increment: step;
  position: relative;
  padding: var(--space-6) 0 var(--space-6) clamp(var(--space-8), 5vw, var(--space-12));
  border-top: 1px solid var(--color-on-dark-hairline);
}
.process li:last-child {
  border-bottom: 1px solid var(--color-on-dark-hairline);
}
.process li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: calc(var(--space-6) + 0.35em);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-lime);
  font-variant-numeric: tabular-nums lining-nums;
}
.process h3 {
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 600;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-3);
}
.process h3 span {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-on-dark-muted);
}
.process p {
  margin-top: var(--space-3);
  max-width: 42ch;
  color: var(--color-on-dark-muted);
  font-size: var(--text-sm);
}

/* =============== FIELD =============== */
.section--field {
  background: var(--color-bg);
}

.field-items {
  margin-top: clamp(var(--space-12), 7vw, var(--space-20));
  display: grid;
  gap: clamp(var(--space-10), 5vw, var(--space-16));
}
@media (min-width: 800px) {
  .field-items {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .field-item:nth-child(2) {
    margin-top: var(--space-16);
  }
}
.field-item img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
}
.field-item__cat {
  margin-top: var(--space-5);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-green-text);
}
.field-item h3 {
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 600;
  margin-top: var(--space-2);
}
.field-item p:not(.field-item__cat) {
  margin-top: var(--space-3);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  max-width: 44ch;
}
.field-more {
  margin-top: clamp(var(--space-10), 5vw, var(--space-16));
}

/* =============== ALUMNI =============== */
.section--alumni {
  background: var(--color-surface);
  border-block: 1px solid var(--color-border);
}
.alumni__head {
  max-width: var(--content-default);
}
.alumni__head .section-title {
  font-size: var(--text-2xl);
}
.offer {
  margin-top: clamp(var(--space-12), 7vw, var(--space-20));
  display: grid;
  gap: 0;
  border-top: 1px solid var(--color-hairline);
}
.offer > div {
  padding-block: var(--space-8);
  border-bottom: 1px solid var(--color-border);
  display: grid;
  gap: var(--space-3);
}
@media (min-width: 800px) {
  .offer > div {
    grid-template-columns: minmax(0, 18rem) minmax(0, 1fr);
    gap: var(--space-10);
    align-items: baseline;
  }
}
.offer dt {
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 600;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-3);
}
.offer dt span {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-faint);
}
.offer dd {
  color: var(--color-text-muted);
  max-width: 52ch;
}
.alumni__cta {
  margin-top: clamp(var(--space-10), 5vw, var(--space-16));
  max-width: 52ch;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}
.alumni__cta .link-arrow {
  margin-inline-start: var(--space-1);
}

/* =============== APPLY =============== */
.apply {
  background: var(--color-forest);
  color: var(--color-on-dark);
  padding-block: clamp(var(--space-20), 12vw, var(--space-32));
}
.apply__title {
  font-family: var(--font-serif);
  font-size: var(--text-2xl);
  font-weight: 600;
  line-height: 1.22;
  margin-top: var(--space-5);
  max-width: 24ch;
}
.apply__note {
  margin-top: var(--space-6);
  max-width: 40ch;
  color: var(--color-on-dark-muted);
}
.apply .btn {
  margin-top: clamp(var(--space-8), 4vw, var(--space-12));
}

/* =============== FOOTER =============== */
.site-footer {
  background: var(--color-bg);
  padding-block: clamp(var(--space-12), 6vw, var(--space-16));
  border-top: 1px solid var(--color-border);
  font-size: var(--text-sm);
}
.site-footer__inner {
  display: grid;
  gap: var(--space-8);
}
@media (min-width: 900px) {
  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr) auto auto;
    align-items: start;
    column-gap: var(--space-16);
  }
}
.site-footer__brand {
  display: flex;
  align-items: center;
}
.site-footer__nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3) var(--space-6);
}
.site-footer__nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--color-text-muted);
}
.site-footer__nav a:hover {
  color: var(--color-text);
}
.social {
  list-style: none;
  display: flex;
  gap: var(--space-2);
}
.social a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}
.social a:hover {
  color: var(--color-text);
  border-color: var(--color-hairline);
}

/* =============== BRAND LOGO (official Youth Council mark) =============== */
/* The source artwork and 900x571 aspect ratio are preserved. Light mode uses the
   official greens; dark mode uses a contextual monochrome treatment so the whole
   co-brand lockup sits directly on the header/footer without a contrasting plate. */
.brand__logo {
  display: block;
  width: auto;
  /* Height-driven so the aspect ratio (900:571) is exact and the
     "Youth Council 青年議會" wordmark stays readable. */
  height: 3.375rem;
  flex: none;
  object-fit: contain;
}
@media (max-width: 860px) {
  .brand__logo {
    height: 2.875rem;
  }
}
@media (max-width: 380px) {
  .brand__logo {
    height: 2.5rem;
  }
}

/* Dark mode: remove the former warm-white plate. The transparent official artwork
   becomes a restrained warm-white monochrome mark and the adjacent real text uses
   the same on-dark ramp, keeping the full lockup legible and background-matched. */
[data-theme='dark'] .site-header .brand__logo,
[data-theme='dark'] .brand--footer .brand__logo {
  filter: brightness(0) invert(1);
  opacity: 0.9;
}
[data-theme='dark'] .site-header .brand .brand__name,
[data-theme='dark'] .brand--footer .brand__name {
  color: var(--color-on-dark);
}
[data-theme='dark'] .site-header .brand .brand__sub,
[data-theme='dark'] .brand--footer .brand__sub {
  color: var(--color-on-dark-muted);
}
.brand--footer {
  display: inline-flex;
  align-items: center;
  gap: clamp(0.5rem, 1.2vw, var(--space-4));
  color: var(--color-text);
}
.brand__logo--footer {
  height: 3.5rem;
}
@media (max-width: 640px) {
  .brand__logo--footer {
    height: 2.875rem;
  }
}
/* =============== YOUTH COUNCIL BRAND PANEL =============== */
.yc-panel {
  margin-top: clamp(var(--space-16), 9vw, var(--space-24));
  display: grid;
  gap: clamp(var(--space-8), 4vw, var(--space-16));
  align-items: center;
  padding-top: clamp(var(--space-12), 6vw, var(--space-16));
  border-top: 1px solid var(--color-hairline);
}
@media (min-width: 860px) {
  .yc-panel {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  }
}
.yc-panel__visual {
  background: #fcfef9;
  border: 1px solid var(--color-border);
  border-top: 2px solid var(--color-leaf);
  border-radius: var(--radius-lg);
  padding: clamp(var(--space-5), 3vw, var(--space-8));
}
.yc-panel__visual img {
  width: 100%;
  border-radius: var(--radius-sm);
}
/* Official Youth Council logo: never stretched, always on the warm-white plate so
   the dark-green wordmark stays legible in dark mode without altering brand colours. */
.yc-panel__visual .yc-panel__logo {
  display: block;
  width: 100%;
  max-width: 22rem;
  height: auto;
  margin-inline: auto;
  padding-block: clamp(var(--space-2), 1.5vw, var(--space-4));
  border-radius: 0;
}
.yc-panel__title {
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  font-weight: 600;
  margin-block: var(--space-4) var(--space-5);
}
.yc-panel__body > p {
  max-width: 46ch;
  color: var(--color-text-muted);
}
.yc-aims {
  margin-top: var(--space-6);
  border-top: 1px solid var(--color-border);
}
.yc-aims li {
  padding-block: var(--space-4);
  border-bottom: 1px solid var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text);
  position: relative;
  padding-inline-start: var(--space-6);
}
.yc-aims li::before {
  content: '';
  position: absolute;
  left: 0;
  top: calc(var(--space-4) + 0.7em);
  width: 10px;
  height: 1px;
  background: var(--color-green);
}

/* =============== PROGRAMME NOTE =============== */
.journey__note {
  margin-top: var(--space-4);
  padding-inline-start: var(--space-5);
  border-inline-start: 1px solid var(--color-green);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 48ch;
}

/* =============== ALUMNI STATUS =============== */
.alumni__status {
  margin-top: var(--space-5);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-green-text);
  border: 1px solid color-mix(in oklab, var(--color-green) 45%, transparent);
  border-radius: var(--radius-sm);
  padding: var(--space-1) var(--space-3);
}