/* ═══════════════════════════════════════════════════════
   QCon Sponsor Guide — Redesign v3
   Mobile-first, fully fluid, no max-width boxes
═══════════════════════════════════════════════════════ */

/* ── Design tokens — DARK (default) ── */
:root{
  --ink:      #0A0A0F;
  --paper:    #111118;
  --surface:  #1A1A24;
  --surface2: #22222F;
  --white:    #FFFFFF;
  --text:     #E2E2EC;
  --muted:    #7E7E96;
  --border:   #2A2A3A;

  --before:   #4D8EFF;
  --before-l: rgba(77,142,255,.1);
  --during:   #A67CFF;
  --during-l: rgba(166,124,255,.1);
  --after:    #34D38E;
  --after-l:  rgba(52,211,142,.1);
  --intro:    #FF7A45;
  --intro-l:  rgba(255,122,69,.1);

  --f-display: 'Space Grotesk', system-ui, sans-serif;
  --f-body:    'Inter', system-ui, sans-serif;

  --gx: clamp(20px, 6vw, 80px);
  --gy: clamp(56px, 7vw, 104px);
  --r:  12px;

  /* Nav */
  --nav-bg:        rgba(17,17,24,.92);
  --nav-mobile-bg: rgba(17,17,24,.97);

  /* Hero */
  --hero-bg:           #0A0A0F;
  --hero-text:         #FFFFFF;
  --hero-sub-color:    rgba(255,255,255,.55);
  --hero-right-bg:     #111117;
  --hero-bar-bg:       rgba(10,10,15,.75);
  --hero-chip-border:  rgba(255,255,255,.18);
  --hero-chip-color:   rgba(255,255,255,.7);
  --hero-accent-stroke:#FFFFFF;

  /* Phase stripes */
  --stripe-default-text: rgba(255,255,255,.15);
  --stripe-before-text:  rgba(77,142,255,.4);
  --stripe-during-text:  rgba(166,124,255,.4);

  /* After section */
  --after-bg:           #0A0A0F;
  --after-heading:      #FFFFFF;
  --after-muted:        rgba(255,255,255,.4);
  --after-card-border:  rgba(255,255,255,.08);
  --after-card-bg:      rgba(255,255,255,.04);
  --after-card-hover:   rgba(255,255,255,.08);
  --after-ghost:        rgba(255,255,255,.05);
  --after-h3:           #FFFFFF;
  --after-p:            rgba(255,255,255,.4);

  /* Footer */
  --footer-bg:          #05050A;
  --footer-text:        rgba(255,255,255,.3);
  --footer-link:        rgba(255,255,255,.45);
  --footer-link-hover:  #FFFFFF;
}

/* ── Light theme overrides — MUST come after :root ── */
[data-theme="light"]{
  --paper:    #F5F5F7;
  --surface:  #FFFFFF;
  --surface2: #EEEEF2;
  --text:     #0A0A0F;
  --muted:    #6E6E82;
  --border:   #DDDDE8;

  --before:   #0055DD;
  --before-l: rgba(0,85,221,.08);
  --during:   #6C35D9;
  --during-l: rgba(108,53,217,.08);
  --after:    #00875A;
  --after-l:  rgba(0,135,90,.08);
  --intro:    #D94F00;
  --intro-l:  rgba(217,79,0,.08);

  /* Nav */
  --nav-bg:        rgba(245,245,247,.92);
  --nav-mobile-bg: rgba(245,245,247,.97);

  /* Hero — lighter palette */
  --hero-bg:           #1A1A2E;
  --hero-text:         #FFFFFF;
  --hero-sub-color:    rgba(255,255,255,.6);
  --hero-right-bg:     #12121F;
  --hero-bar-bg:       rgba(10,10,20,.75);
  --hero-chip-border:  rgba(255,255,255,.2);
  --hero-chip-color:   rgba(255,255,255,.75);
  --hero-accent-stroke:#FFFFFF;

  /* Phase stripes */
  --stripe-default-text: rgba(0,0,0,.12);
  --stripe-before-text:  rgba(0,85,221,.4);
  --stripe-during-text:  rgba(108,53,217,.4);

  /* After — stays dark for visual weight */
  --after-bg:           #13131F;
  --after-heading:      #FFFFFF;
  --after-muted:        rgba(255,255,255,.4);
  --after-card-border:  rgba(255,255,255,.1);
  --after-card-bg:      rgba(255,255,255,.05);
  --after-card-hover:   rgba(255,255,255,.1);
  --after-ghost:        rgba(255,255,255,.05);
  --after-h3:           #FFFFFF;
  --after-p:            rgba(255,255,255,.4);

  /* Footer */
  --footer-bg:          #0A0A12;
  --footer-text:        rgba(255,255,255,.3);
  --footer-link:        rgba(255,255,255,.45);
  --footer-link-hover:  #FFFFFF;
}

/* ── Base ── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;font-size:16px;}
body{
  font-family:var(--f-body);
  background:var(--paper);
  color:var(--text);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{display:block;max-width:100%;}
p{margin-bottom:1em;}p:last-child{margin-bottom:0;}
a{color:var(--before);text-underline-offset:3px;}

/* ── Reading progress ── */
.rp{
  position:fixed;top:0;left:0;right:0;height:3px;z-index:500;
  background:linear-gradient(90deg,var(--before),var(--during),var(--after));
  transform:scaleX(0);transform-origin:left;
  transition:transform .08s linear;
}

/* ── Nav ── */
.nav{
  position:sticky;top:0;z-index:400;
  display:flex;align-items:center;justify-content:space-between;
  padding:0 var(--gx);height:56px;
  background:var(--nav-bg);
  backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid transparent;
  transition:border-color .2s,box-shadow .2s,background .3s;
}
.nav.scrolled{border-bottom-color:var(--border);box-shadow:0 1px 16px rgba(0,0,0,.25);}
.nav-logo{display:flex;align-items:center;gap:10px;font-size:.9rem;font-weight:500;text-decoration:none;color:var(--text);}
.nav-logo b{font-weight:700;}
.nav-logo-mark{
  width:30px;height:30px;border-radius:8px;
  background:var(--before);color:#fff;
  font-family:var(--f-display);font-size:.95rem;font-weight:700;
  display:grid;place-items:center;flex-shrink:0;
}
.nav-links{display:flex;gap:4px;list-style:none;}
.nav-links a{
  display:block;padding:5px 14px;border-radius:99px;
  font-size:.82rem;font-weight:500;color:var(--muted);
  text-decoration:none;transition:background .15s,color .15s;
}
.nav-links a:hover,.nav-links a.active{background:var(--surface2);color:var(--text);}
.nav-burger{
  display:none;flex-direction:column;justify-content:center;gap:6px;
  width:38px;height:38px;background:none;border:none;cursor:pointer;
}
.nav-burger span{display:block;width:22px;height:2px;background:var(--text);border-radius:2px;transition:transform .2s,opacity .2s;}
.nav-burger.open span:first-child{transform:translateY(8px) rotate(45deg);}
.nav-burger.open span:last-child{transform:translateY(-8px) rotate(-45deg);}

/* ── HERO ── */
.hero{
  display:grid;
  grid-template-columns:1fr 1fr;
  min-height:88vh;
  background:var(--hero-bg);
  color:var(--hero-text);
  overflow:hidden;
  transition:background .3s;
}
.hero-left{
  display:flex;flex-direction:column;justify-content:center;
  padding:clamp(40px,6vw,80px) 0 clamp(40px,6vw,80px) var(--gx);
  padding-right:clamp(24px,4vw,56px);
}
.hero-kicker{
  font-size:.72rem;font-weight:600;letter-spacing:.14em;
  text-transform:uppercase;opacity:.4;margin-bottom:20px;
}
.hero-h1{
  font-family:var(--f-display);
  font-size:clamp(2.8rem,5.5vw,5.5rem);
  font-weight:700;line-height:1.1;
  letter-spacing:-.01em;
  margin-bottom:24px;
}
.hero-accent{
  -webkit-text-stroke:2px var(--hero-accent-stroke);
  color:transparent;
  display:block;
}
.hero-sub{
  font-size:clamp(.9rem,1.4vw,1.1rem);
  color:var(--hero-sub-color);
  max-width:380px;margin-bottom:36px;line-height:1.6;
}
.hero-steps{display:flex;flex-wrap:wrap;gap:8px;}
.step-chip{
  display:inline-flex;align-items:center;gap:8px;
  padding:8px 20px;border-radius:99px;
  font-size:.8rem;font-weight:600;
  text-decoration:none;
  border:1px solid var(--hero-chip-border);
  color:var(--hero-chip-color);
  transition:all .18s;
}
.step-chip span{font-size:.65rem;opacity:.45;}
.step-chip:hover{color:#fff;border-color:rgba(255,255,255,.5);transform:translateY(-2px);}
.step-before:hover{background:rgba(77,142,255,.25);border-color:rgba(77,142,255,.6);}
.step-during:hover{background:rgba(166,124,255,.25);border-color:rgba(166,124,255,.6);}
.step-after:hover {background:rgba(52,211,142,.2);border-color:rgba(52,211,142,.5);}

/* hero right */
.hero-right{
  position:relative;overflow:hidden;
  background:var(--hero-right-bg);
  transition:background .3s;
}
.hero-photo{
  width:100%;height:100%;
  object-fit:cover;object-position:center;
  opacity:.65;
  filter:saturate(1.1);
  transition:opacity .3s;
}
.hero-right:hover .hero-photo{opacity:.8;}
.hero-card{position:relative;height:100%;display:flex;flex-direction:column;}
.hero-card-bar{
  position:absolute;bottom:0;left:0;right:0;
  display:flex;align-items:center;
  padding:18px 24px;
  background:var(--hero-bar-bg);
  backdrop-filter:blur(12px);
  transition:background .3s;
}
.hcb-item{display:flex;flex-direction:column;align-items:center;gap:2px;flex:1;}
.hcb-num{font-family:var(--f-display);font-size:1.5rem;font-weight:700;color:#fff;line-height:1;}
.hcb-label{font-size:.65rem;font-weight:500;color:rgba(255,255,255,.4);letter-spacing:.1em;text-transform:uppercase;}
.hcb-sep{width:1px;height:28px;background:rgba(255,255,255,.12);}

/* ── Section common ── */
.s-head{margin-bottom:clamp(28px,3.5vw,48px);}
.s-head h2{
  font-family:var(--f-display);
  font-size:clamp(1.8rem,3vw,2.6rem);
  font-weight:700;line-height:1.2;
  letter-spacing:-.01em;
  margin-top:8px;
}
.tag{
  display:inline-block;
  font-size:.68rem;font-weight:700;letter-spacing:.1em;
  text-transform:uppercase;padding:4px 12px;border-radius:4px;
}
.tag-intro { background:var(--intro-l);  color:var(--intro); }
.tag-before{ background:var(--before-l); color:var(--before);}
.tag-during{ background:var(--during-l); color:var(--during);}
.tag-after { background:var(--after-l);  color:var(--after); }

/* ── Intro section ── */
.s-intro{padding:var(--gy) var(--gx);background:var(--surface);}
.intro-body{
  display:grid;grid-template-columns:1.3fr 1fr;
  gap:clamp(24px,4vw,64px);align-items:start;
}
.intro-lead{font-size:1.15rem;font-weight:600;color:var(--intro);margin-bottom:16px;}
.intro-prose p{color:var(--muted);}
.intro-phases{display:flex;flex-direction:column;gap:12px;}
.phase-card{
  display:flex;align-items:center;gap:16px;
  padding:18px 20px;border-radius:var(--r);
  border:1px solid var(--border);
  background:var(--surface2);
  transition:transform .18s,border-color .18s;
}
.phase-card:hover{transform:translateX(4px);border-color:currentColor;}
.phase-before{color:var(--before);}
.phase-during{color:var(--during);}
.phase-after {color:var(--after);}
.pc-num{font-family:var(--f-display);font-size:1.8rem;font-weight:700;line-height:1;flex-shrink:0;opacity:.2;}
.pc-body{flex:1;}
.pc-body strong{display:block;font-size:.95rem;font-weight:600;color:var(--text);}
.pc-body span  {display:block;font-size:.78rem;color:var(--muted);}
.pc-arrow{font-size:1.2rem;flex-shrink:0;text-decoration:none;opacity:.3;transition:opacity .15s;}
.phase-card:hover .pc-arrow{opacity:1;}

/* ── Phase sections ── */
.s-phase{display:grid;grid-template-columns:56px 1fr;width:100%;}
.phase-stripe{
  background:var(--surface2);
  display:flex;align-items:flex-start;justify-content:center;
  padding-top:calc(var(--gy) + 14px);
  border-right:1px solid var(--border);
  transition:background .3s,border-color .3s;
}
.phase-stripe span{
  font-family:var(--f-display);font-weight:700;font-size:1rem;
  color:var(--stripe-default-text);
  writing-mode:vertical-rl;letter-spacing:.15em;text-transform:uppercase;
  transition:color .3s;
}
.s-before .phase-stripe span{color:var(--stripe-before-text);}
.s-during .phase-stripe span{color:var(--stripe-during-text);}
.phase-content{padding:var(--gy) var(--gx);}
.s-before .phase-content{background:var(--paper);}
.s-during .phase-content{background:var(--surface);}

/* ── Block ── */
.block{
  padding:clamp(20px,3vw,36px);
  border-radius:var(--r);
  border:1px solid var(--border);
  background:var(--surface);
  margin-bottom:clamp(14px,2vw,20px);
}
.s-during .phase-content .block{background:var(--surface2);}
.block-label{font-size:.68rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin-bottom:10px;}
.block h3{
  font-family:var(--f-display);font-size:clamp(1.05rem,1.8vw,1.35rem);
  font-weight:700;letter-spacing:0;margin-bottom:16px;
  line-height:1.3;color:var(--text);
}
.block p{font-size:.95rem;color:var(--muted);}

/* ── Check grid ── */
.check-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:10px;margin:14px 0;}
.check-item{
  display:flex;align-items:baseline;gap:10px;
  padding:12px 14px;border-radius:8px;
  background:var(--surface2);
  font-size:.88rem;color:var(--text);
  border:1px solid var(--border);
}
.s-during .phase-content .check-item{background:var(--paper);}
.ci-dot{width:8px;height:8px;border-radius:50%;background:var(--before);flex-shrink:0;margin-top:4px;}
.s-during .ci-dot{background:var(--during);}

/* ── two-up ── */
.two-up{display:grid;grid-template-columns:1fr 1fr;gap:clamp(12px,2vw,20px);margin:14px 0;}
.mt{margin-top:16px;}

/* ── spec box ── */
.spec-box{
  background:var(--surface2);
  border:1px solid var(--border);
  border-radius:var(--r);
  padding:20px 22px;font-size:.88rem;
}
.spec-during{border-color:rgba(166,124,255,.2);}
.spec-icon{font-size:1.5rem;margin-bottom:8px;}
.spec-title{font-size:.7rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--before);margin-bottom:10px;}
.spec-during .spec-title{color:var(--during);}
.spec-box ul{list-style:none;display:flex;flex-direction:column;gap:6px;}
.spec-box li{padding-left:14px;position:relative;font-size:.88rem;color:var(--muted);}
.spec-box li::before{content:'—';position:absolute;left:0;color:var(--border);font-size:.75rem;}
.spec-box p{margin-top:10px;font-size:.82rem;color:var(--muted);}

/* ── alerts ── */
.alert{display:flex;gap:12px;align-items:flex-start;padding:14px 18px;border-radius:8px;font-size:.9rem;margin:14px 0;color:var(--text);}
.alert>span{font-size:1.1rem;flex-shrink:0;margin-top:1px;}
.alert-tip  {background:rgba(52,211,142,.08);border:1px solid rgba(52,211,142,.2);}
.alert-warn {background:rgba(251,191,36,.07);border:1px solid rgba(251,191,36,.25);border-left:3px solid rgba(251,191,36,.6);}
.alert-brand{background:var(--before-l);border:1px solid rgba(77,142,255,.2);}
.ml-list{list-style:none;margin-top:8px;display:flex;flex-direction:column;gap:5px;}
.ml-list li{padding-left:14px;position:relative;font-size:.88rem;color:var(--muted);}
.ml-list li::before{content:'·';position:absolute;left:4px;color:var(--muted);}

/* ── feature row ── */
.feature-row{display:flex;gap:14px;align-items:flex-start;padding:18px;border-radius:var(--r);border:1px solid var(--border);background:var(--surface2);}
.s-during .feature-row{background:var(--paper);}
.fr-icon{font-size:1.5rem;flex-shrink:0;}
.feature-row strong{display:block;font-size:.9rem;font-weight:700;margin-bottom:4px;color:var(--text);}
.feature-row p{font-size:.84rem;color:var(--muted);margin:0;}

/* ── tiers ── */
.tier-list{display:flex;flex-direction:column;gap:10px;margin-top:16px;}
.tier{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;border-radius:var(--r);font-size:.9rem;color:var(--text);border:1px solid var(--border);background:var(--surface2);}
.tier span:last-child{color:var(--muted);font-size:.85rem;}
.tier-badge{font-weight:700;}
.tier-gold  {border-color:rgba(251,191,36,.35);}
.tier-silver{border-color:rgba(148,163,184,.25);}
.tier-bronze{border-color:rgba(217,119,6,.3);}

/* ── spotlight ── */
.spotlight{
  display:flex;gap:16px;align-items:flex-start;
  padding:clamp(18px,2.5vw,28px);
  background:var(--during-l);
  border:1px solid rgba(166,124,255,.2);
  border-radius:var(--r);margin-bottom:24px;
  font-size:.95rem;font-style:italic;color:var(--text);
}
.sl-icon{font-size:1.6rem;flex-shrink:0;}

/* ── expander ── */
.expander{margin-top:14px;border-top:1px solid var(--border);padding-top:12px;}
.expander summary{cursor:pointer;font-weight:600;font-size:.9rem;color:var(--during);list-style:none;display:flex;align-items:center;gap:8px;user-select:none;}
.expander summary::before{content:'›';font-size:1.1rem;transition:transform .2s;}
.expander[open] summary::before{transform:rotate(90deg);}
.expander-body{padding-top:14px;display:flex;flex-direction:column;gap:10px;}
.expander-body p{font-size:.88rem;color:var(--muted);}

/* ── After ── */
.s-after{
  padding:var(--gy) var(--gx);
  background:var(--after-bg);
  transition:background .3s;
}
.s-after .s-head h2{color:var(--after-heading);}
.s-after .tag-after{background:var(--after-l);color:var(--after);}
.after-row{display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(12px,2vw,20px);}
.af-card{
  position:relative;overflow:hidden;
  padding:clamp(24px,3vw,36px);
  border-radius:var(--r);
  border:1px solid var(--after-card-border);
  background:var(--after-card-bg);
  transition:background .2s,transform .2s,border-color .3s;
}
.af-card:hover{background:var(--after-card-hover);transform:translateY(-4px);}
.af-card::after{content:'';position:absolute;bottom:0;left:0;right:0;height:2px;}
.af-card:nth-child(1)::after{background:var(--before);}
.af-card:nth-child(2)::after{background:var(--during);}
.af-card:nth-child(3)::after{background:var(--after);}
.af-n{font-family:var(--f-display);font-size:3.5rem;font-weight:700;line-height:1;color:var(--after-ghost);position:absolute;top:16px;right:20px;}
.af-icon{font-size:1.8rem;margin-bottom:12px;}
.af-card h3{font-family:var(--f-display);font-size:1.1rem;font-weight:700;margin-bottom:10px;color:var(--after-h3);letter-spacing:0;}
.af-card p{font-size:.88rem;color:var(--after-p);}

/* ── foot-note ── */
.foot-note{font-size:.82rem;color:var(--muted);margin-top:10px;}

/* ── Footer ── */
.footer{
  background:var(--footer-bg);
  color:var(--footer-text);
  padding:36px var(--gx);
  display:flex;flex-direction:column;align-items:center;gap:8px;
  text-align:center;font-size:.85rem;
  transition:background .3s;
}
.footer-logo{margin-bottom:4px;}
.footer a{color:var(--footer-link);}
.footer a:hover{color:var(--footer-link-hover);}

/* ── Theme toggle button ── */
.theme-btn{
  display:flex;align-items:center;gap:6px;
  padding:5px 14px;border-radius:99px;
  font-size:.82rem;font-weight:500;
  border:1px solid var(--border);
  background:none;cursor:pointer;
  color:var(--muted);
  transition:background .15s,color .15s,border-color .15s;
  white-space:nowrap;
}
.theme-btn:hover{background:var(--surface2);color:var(--text);}
.theme-btn .tb-icon{font-size:1rem;line-height:1;}
.theme-btn .tb-label{display:none;}
@media(min-width:480px){.theme-btn .tb-label{display:inline;}}

/* ── Reveal animations ── */
.pre{opacity:0;transform:translateY(24px);transition:opacity .5s ease,transform .5s ease;}
.pre.in{opacity:1;transform:none;}

/* ═══════════════════
   RESPONSIVE
═══════════════════ */
@media(max-width:900px){
  .hero{grid-template-columns:1fr;min-height:auto;}
  .hero-right{height:280px;}
  .intro-body{grid-template-columns:1fr;}
  .two-up{grid-template-columns:1fr;}
  .after-row{grid-template-columns:1fr 1fr;}
}

@media(max-width:600px){
  .nav-burger{display:flex;}
  .nav-links{
    display:none;position:fixed;top:56px;left:0;right:0;
    background:var(--nav-mobile-bg);backdrop-filter:blur(16px);
    flex-direction:column;gap:0;list-style:none;
    border-bottom:1px solid var(--border);
    padding:6px 0 10px;box-shadow:0 8px 24px rgba(0,0,0,.4);
    transition:background .3s;
  }
  .nav-links.open{display:flex;}
  .nav-links a{border-radius:0;padding:13px var(--gx);font-size:.95rem;border-bottom:1px solid var(--border);color:var(--text);}
  .nav-links li:last-child a{border-bottom:none;}

  .hero{grid-template-columns:1fr;}
  .hero-right{height:220px;}
  .hero-h1{font-size:clamp(2.6rem,11vw,3.8rem);}
  .s-phase{grid-template-columns:36px 1fr;}
  .after-row{grid-template-columns:1fr;}
  .check-grid{grid-template-columns:1fr;}
}