/* ============================================================================
   SYHF 2026 — Stage theme + subthemes (assets/js/stage-theme.js)
   Sits above the agenda reel. The page opens on what the Stage is ABOUT;
   the schedule is one button, or one scroll, further down.
   Dark surface, sharing the Stage page's arena backdrop.
   ========================================================================== */
.theme { position: relative; z-index: 2; padding-block: clamp(4rem, 10vw, 8rem) clamp(3rem, 7vw, 5rem); }
.theme__inner { width: min(72rem, calc(100% - 2 * var(--gutter))); margin-inline: auto; }

.theme__kicker { margin: 0 0 var(--space-3); font-size: 0.82rem; font-weight: 700;
  letter-spacing: 0.2em; text-transform: uppercase; color: var(--syhs-tint-mint); }
#stage-theme .theme__title { margin: 0 0 var(--space-4); font-weight: 800;
  font-size: clamp(2.4rem, 1.2rem + 5.4vw, 5.4rem); line-height: 0.98;
  letter-spacing: var(--tracking-tighter); text-transform: uppercase; color: #fff; }
#stage-theme .theme__title em { font-family: var(--font-serif); font-style: italic;
  font-weight: 500; text-transform: none; letter-spacing: var(--tracking-tight);
  background: linear-gradient(100deg, var(--syhs-tint-mint), var(--syhs-tint-violet));
  -webkit-background-clip: text; background-clip: text; color: transparent; }
.theme__lede { margin: 0 0 clamp(2.5rem, 6vw, 4rem); max-width: 56ch;
  font-size: var(--fs-body-lg); line-height: 1.6; color: rgba(255,255,255,0.86); }

.theme__sub-head { margin: 0 0 var(--space-4); font-family: var(--font-serif);
  font-style: italic; font-weight: 500; font-size: var(--fs-h2); color: #fff; }

/* --- The five subthemes -------------------------------------------------- */
.subthemes { list-style: none; margin: 0 0 clamp(2.5rem, 6vw, 4rem); padding: 0;
  display: grid; gap: clamp(1rem, 2.5vw, 1.5rem);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr)); }

.subtheme { position: relative; overflow: hidden; padding: clamp(1.25rem, 3vw, 1.9rem);
  border-radius: var(--radius-md); border: 1px solid rgba(255,255,255,0.18);
  background: linear-gradient(168deg, color-mix(in srgb, var(--syhs-ink) 34%, transparent),
                                      color-mix(in srgb, var(--syhs-ink) 56%, transparent));
  transition: transform 240ms var(--ease-editorial), border-color 240ms; }
.subtheme::before { content: ""; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(90% 70% at 20% 0%, rgba(var(--t-rgb), 0.4), transparent 72%);
  transition: background 240ms var(--ease-editorial); }
.subtheme > * { position: relative; z-index: 1; }
.subtheme::after { content: ""; position: absolute; inset: auto 0 0 0; height: 3px;
  background: linear-gradient(90deg, var(--t1), transparent); }
.subtheme:hover { transform: translateY(-8px);
  border-color: color-mix(in srgb, var(--t1) 60%, transparent);
  box-shadow: 0 24px 40px -20px rgba(var(--t-rgb), 0.55); }

/* Diagonal light sweep on hover — a moving highlight, not a static glow. */
.subtheme__shine { position: absolute; inset: 0; z-index: 1; pointer-events: none;
  background: linear-gradient(120deg, transparent 40%, rgba(255,255,255,0.16) 50%, transparent 60%);
  background-size: 250% 100%; background-position: -100% 0; opacity: 0; }
.subtheme:hover .subtheme__shine { opacity: 1; animation: subtheme-shine 1.6s ease; }
@keyframes subtheme-shine { from { background-position: -100% 0; } to { background-position: 200% 0; } }

/* The ambient radial (::before) blooms brighter under the cursor, echoing
   the lift and the shine instead of sitting static underneath them. */
.subtheme:hover::before { background: radial-gradient(90% 70% at 20% 0%, rgba(var(--t-rgb), 0.62), transparent 72%); }

/* One colour per subtheme, all from locked tokens. */
.subtheme[data-tone="a"] { --t1: var(--syhs-tint-mint);   --t-rgb: var(--syhs-tint-mint-rgb); }
.subtheme[data-tone="b"] { --t1: var(--syhs-tint-violet); --t-rgb: var(--syhs-tint-violet-rgb); }
.subtheme[data-tone="c"] { --t1: var(--syhs-tint-sky);    --t-rgb: var(--syhs-navy-rgb); }
.subtheme[data-tone="d"] { --t1: var(--syhs-signal-alt);  --t-rgb: var(--syhs-signal-rgb); }
.subtheme[data-tone="e"] { --t1: var(--syhs-tint-mint);   --t-rgb: var(--syhs-tint-mint-rgb); }

.subtheme__icon { display: grid; place-items: center; width: 54px; height: 54px;
  margin-bottom: var(--space-3); border-radius: 14px; color: var(--syhs-ground);
  background: var(--t1); transition: transform 280ms var(--ease-editorial), box-shadow 280ms var(--ease-editorial); }
.subtheme__icon svg { width: 62%; height: 62%; }
.subtheme:hover .subtheme__icon { transform: scale(1.08) translateY(-2px);
  box-shadow: 0 10px 22px -8px rgba(var(--t-rgb), 0.7); }
.subtheme__name { margin: 0 0 0.8rem; font-size: 1.2rem; font-weight: 700;
  line-height: 1.2; letter-spacing: var(--tracking-tight); color: #fff;
  transition: color 240ms, transform 240ms; }
.subtheme:hover .subtheme__name { color: var(--t1); transform: translateX(2px); }
.subtheme__points { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.45rem; }
.subtheme__points li { position: relative; padding-inline-start: 1.05rem;
  font-size: 0.95rem; line-height: 1.45; color: rgba(255,255,255,0.84); }
.subtheme__points li::before { content: ""; position: absolute; inset-inline-start: 0; top: 0.55em;
  width: 5px; height: 5px; border-radius: 50%; background: var(--t1); }

/* --- Go to the agenda ---------------------------------------------------- */
.theme__go { display: flex; align-items: center; gap: var(--space-4); flex-wrap: wrap; }
.theme__btn { display: inline-flex; align-items: center; gap: 0.6rem; text-decoration: none;
  font-weight: 700; font-size: 1.1rem; min-height: 56px; padding: 1rem 2rem;
  border-radius: 999px; background: var(--syhs-tint-mint); color: var(--syhs-ground);
  transition: transform 200ms, filter 200ms; }
.theme__btn:hover { transform: translateY(-2px); filter: brightness(1.06); }
.theme__btn:focus-visible { outline: 3px solid #fff; outline-offset: 3px; }
.theme__scroll-hint { margin: 0; font-size: 0.95rem; color: rgba(255,255,255,0.7); }
.theme__scroll-hint::before { content: "\2193"; margin-inline-end: 0.4rem;
  display: inline-block; animation: theme-nudge 1.8s ease-in-out infinite; }
@keyframes theme-nudge { 0%,100% { transform: translateY(0); } 50% { transform: translateY(4px); } }

@media (prefers-reduced-motion: reduce) {
  .subtheme, .theme__btn, .subtheme__icon, .subtheme__name { transition: none; }
  .subtheme:hover, .theme__btn:hover, .subtheme:hover .subtheme__icon, .subtheme:hover .subtheme__name { transform: none; }
  .subtheme:hover .subtheme__shine { animation: none; opacity: 0; }
  .theme__scroll-hint::before { animation: none; }
}

/* --- Mobile is authored, not shrunk -------------------------------------- */
/* The stage nav is fixed and grows taller once the brand wraps, so the theme
   clears it explicitly rather than trusting a vw-scaled padding. */
@media (max-width: 47.99em) {
  .theme { padding-block: 7.5rem 3rem; }
  #stage-theme .theme__title { font-size: clamp(2.2rem, 1rem + 9vw, 3.2rem); line-height: 1.02; }
  .theme__lede { font-size: 1.0625rem; line-height: 1.55; margin-bottom: 2.5rem; }
  .theme__sub-head { font-size: 1.75rem; }
  .subtheme { padding: 1.25rem 1.15rem; }
  .subtheme__icon { width: 46px; height: 46px; border-radius: 12px; }
  .subtheme__name { font-size: 1.1rem; }
  .theme__go { gap: var(--space-3); }
  .theme__btn { width: 100%; justify-content: center; }
}