/* Review-only material studies. Original v420 CSS and task engine remain intact. */
:root[data-palette="emerald"] {
  --app-bg:#eaf3ed; --app-surface:#fbfefb; --app-ink:#183d31; --app-muted:#4b6658;
  --app-line:#b9d0c2; --app-green:#116b50; --app-soft:#dcece1; --app-focus:#146c50;
  --studio-canvas:radial-gradient(ellipse at 90% 0%,#c8e7d7 0,transparent 48%),linear-gradient(130deg,#f3f8f1,#e3f0e9);
  --studio-hero:linear-gradient(125deg,#075840,#167d5f); --studio-hero-ink:#fffdf5; --studio-hero-muted:#effaf2;
  --studio-hero-accent:#dceab7; --studio-hero-line:#b4d6bc66;
  --studio-btn:linear-gradient(145deg,#197a59,#0b5c45); --studio-btn-line:#388b6a; --studio-btn-shadow:#084934;
  --studio-nav:linear-gradient(165deg,#d9ece0,#c9e1d3); --studio-nav-ink:#254e3b; --studio-nav-muted:#456450; --studio-nav-line:#9cbaa9;
  --studio-selected:linear-gradient(135deg,#197957,#0b5c43); --studio-selected-ink:#ffffff;
  --studio-number:#e9dec6; --studio-number-ink:#654d2f; --studio-note:#a88657;
  --studio-card-shadow:0 2px 3px #173b2910,0 12px 30px #1d493414; --studio-control:#789588;
}
:root[data-palette="linen"] {
  --app-bg:#f2eee3; --app-surface:#fffcf4; --app-ink:#304333; --app-muted:#5c6853;
  --app-line:#cbcdbc; --app-green:#3e6242; --app-soft:#e1e8d3; --app-focus:#3e6441;
  --studio-canvas:radial-gradient(ellipse at 94% 0%,#dce7cf 0,transparent 50%),linear-gradient(120deg,#f8f5ec,#eee7d7);
  --studio-hero:linear-gradient(120deg,#d7e5cc,#ede2c9); --studio-hero-ink:#28442d; --studio-hero-muted:#475c3f;
  --studio-hero-accent:#426340; --studio-hero-line:#9dab8166;
  --studio-btn:linear-gradient(145deg,#536f47,#37583d); --studio-btn-line:#73896a; --studio-btn-shadow:#2e4830;
  --studio-nav:linear-gradient(160deg,#e8e0cc,#dad8bd); --studio-nav-ink:#354b34; --studio-nav-muted:#536148; --studio-nav-line:#b5b499;
  --studio-selected:linear-gradient(135deg,#526e45,#3a573b); --studio-selected-ink:#fffdf4;
  --studio-number:#e8d9be; --studio-number-ink:#745239; --studio-note:#ac8158;
  --studio-card-shadow:0 2px 3px #6855370a,0 12px 30px #64532d12; --studio-control:#888f79;
}
:root[data-palette="sand"] {
  --app-bg:#235244; --app-surface:#f4ecde; --app-ink:#fff9ee; --app-muted:#e3eee0;
  --app-line:#749181; --app-green:#d3e6bc; --app-soft:#3e6650; --app-focus:#efdbaf;
  --studio-canvas:radial-gradient(ellipse at 90% 0%,#466f51 0,transparent 54%),linear-gradient(145deg,#2c5c49,#1c493e);
  --studio-hero:linear-gradient(125deg,#a8c29b,#d6d8b6); --studio-hero-ink:#203f2b; --studio-hero-muted:#354d33;
  --studio-hero-accent:#395a30; --studio-hero-line:#70856166;
  --studio-btn:linear-gradient(145deg,#49684b,#31513e); --studio-btn-line:#68836a; --studio-btn-shadow:#254332;
  --studio-nav:linear-gradient(165deg,#183f33,#15372e); --studio-nav-ink:#fbf5e7; --studio-nav-muted:#d4e0c8; --studio-nav-line:#65816a;
  --studio-selected:linear-gradient(145deg,#efddbd,#dcc09a); --studio-selected-ink:#3e4e32;
  --studio-number:#ddc5a0; --studio-number-ink:#674d31; --studio-note:#ae855a;
  --studio-card-shadow:0 2px 4px #102e2530,0 12px 28px #092c2530; --studio-control:#8a927d;
}
html[data-palette]:not([data-palette="original"]) {color-scheme:light;--app-shadow:var(--studio-card-shadow)}
html[data-palette]:not([data-palette="original"]) body {background:var(--studio-canvas);background-attachment:fixed;color:var(--app-ink)}
html[data-palette]:not([data-palette="original"]) .app-screen-heading h1 em {color:var(--app-green)}
html[data-palette]:not([data-palette="original"]) .app-eyebrow-line {background:var(--app-green)}
html[data-palette]:not([data-palette="original"]) .app-nav {background:var(--studio-nav);border-color:var(--studio-nav-line);color:var(--studio-nav-ink);box-shadow:inset 0 1px #fff5,0 12px 35px #12372b22}
html[data-palette]:not([data-palette="original"]) .app-nav a {color:var(--studio-nav-ink)}
html[data-palette]:not([data-palette="original"]) .app-nav a[aria-current="page"] {background:var(--studio-selected);color:var(--studio-selected-ink);box-shadow:inset 0 1px #fff4,0 3px 8px #183b3026}
html[data-palette]:not([data-palette="original"]) .app-nav-intro {border-color:var(--studio-nav-line)}
html[data-palette]:not([data-palette="original"]) .app-nav-intro>span {background:#ffffff15;color:var(--studio-nav-ink);border-color:var(--studio-nav-line)}
html[data-palette]:not([data-palette="original"]) .app-nav-intro p {color:var(--studio-nav-muted)}
html[data-palette]:not([data-palette="original"]) .app-nav-site {border-color:var(--studio-nav-line)}
html[data-palette]:not([data-palette="original"]) :is(.app-focus-card,.app-overview,.app-settings-card.tracker-install-card) {background:var(--studio-hero);color:var(--studio-hero-ink);border:1px solid var(--studio-hero-line);box-shadow:inset 0 1px #ffffff42,0 12px 28px #163b2b1c}
html[data-palette]:not([data-palette="original"]) :is(.app-focus-card,.app-overview,.app-settings-card.tracker-install-card) :is(.eyebrow,.app-focus-label,.app-focus-foot,dt,dd small) {color:var(--studio-hero-muted)}
html[data-palette]:not([data-palette="original"]) :is(.app-focus-card,.app-settings-card.tracker-install-card)>p:not(.eyebrow),html[data-palette]:not([data-palette="original"]) .app-settings-card.tracker-install-card p {color:var(--studio-hero-muted)}
html[data-palette]:not([data-palette="original"]) .app-overview p em {color:var(--studio-hero-accent)}
html[data-palette]:not([data-palette="original"]) .app-overview dl>div {border-color:var(--studio-hero-line)}
html[data-palette]:not([data-palette="original"]) .app-step-track span {background:var(--studio-hero-line)}
html[data-palette]:not([data-palette="original"]) .app-step-track .is-complete,html[data-palette]:not([data-palette="original"]) .app-dot {background:var(--studio-hero-accent)}
html[data-palette]:not([data-palette="original"]) .btn-primary:not(.app-focus-card .btn):not(.tracker-install-card .btn),html[data-palette]:not([data-palette="original"]) .tracker-stage-strip .is-current button {background:var(--studio-btn);color:#fffdf3;border-color:var(--studio-btn-line);box-shadow:inset 0 1px #ffffff44,0 3px 0 var(--studio-btn-shadow),0 7px 16px #133f2a18}
html[data-palette]:not([data-palette="original"]) .tracker-stage-strip .is-current button small {color:#edf3e5}
html[data-palette]:not([data-palette="original"]) .tracker-stage-strip .is-current button>span {background:#ffffff20;border-color:#ffffff66;color:#fffdf3}
html[data-palette]:not([data-palette="original"]) :is(.app-focus-card,.tracker-install-card) .btn {background:linear-gradient(145deg,#fff4d8,#e7d7ae);color:#344d2f;border-color:#f3e4c2;box-shadow:inset 0 1px #fff9,0 3px 0 #bda67c,0 7px 16px #183d2d18}
html[data-palette="linen"][data-theme] :is(.app-focus-card,.tracker-install-card) .btn,html[data-palette="sand"][data-theme] :is(.app-focus-card,.tracker-install-card) .btn {background:var(--studio-btn);color:#fffdf3;border-color:var(--studio-btn-line);box-shadow:inset 0 1px #fff4,0 3px 0 var(--studio-btn-shadow),0 7px 16px #133f2a18}
html[data-palette]:not([data-palette="original"]) .app-path-number {background:var(--studio-number);color:var(--studio-number-ink);box-shadow:inset 0 1px #fff8,0 2px 5px #342e1a12}
html[data-palette]:not([data-palette="original"]) .app-path-stages button {background:var(--app-soft);border-color:var(--app-line)}
html[data-palette]:not([data-palette="original"]) .app-path-stages button[aria-current="true"] {background:var(--app-surface);border-color:var(--app-green);box-shadow:inset 0 0 0 1px var(--app-green),0 3px 6px #15352b15}
html[data-palette]:not([data-palette="original"]) .app-path-row[data-active="true"] {border-color:var(--app-green)}
html[data-palette]:not([data-palette="original"]) .app-notebook {border-top-color:var(--studio-note)}
html[data-palette]:not([data-palette="original"]) .tracker-action-card.is-complete {border-left-color:var(--app-green)}
html[data-palette]:not([data-palette="original"]) .is-complete .tracker-task-toggle {background:var(--app-green);color:#fffdf3}
html[data-palette]:not([data-palette="original"]) :is(select,input[type="time"],textarea) {border-color:var(--studio-control)}
html[data-palette]:not([data-palette="original"]) :is(.app-path-stages button,.tracker-task-toggle,.btn-secondary):hover {border-color:var(--app-green);filter:brightness(.98)}
/* Forest & Sand keeps the surrounding green, while the reading surfaces are warm and light. */
html[data-palette="sand"] :is(.app-path-row,.app-progress-card,.app-quick-links a,.app-section-picker,.tracker-stage-strip button,.tracker-action-card,.app-notebook,.app-settings-card,.app-dialog,.app-save-chip,.app-icon-button,.app-save-attention,.app-notice) {
  --app-bg:#ede3d1;--app-surface:#f4ecde;--app-ink:#304334;--app-muted:#5a6653;--app-line:#c3c5ae;--app-green:#3b6445;--app-soft:#e0e5ce;--app-focus:#3d6745;color:var(--app-ink)
}
html[data-palette="sand"] .app-quick-links a,html[data-palette="sand"] .app-save-chip,html[data-palette="sand"] .app-icon-button {background:var(--app-surface)}
html[data-palette="sand"] .app-reset-card {background:var(--app-surface);padding:22px;border-color:var(--app-line)}
html[data-palette="sand"] .app-overview {--app-ink:var(--studio-hero-ink);--app-muted:var(--studio-hero-muted)}
html[data-palette="sand"] .app-topbar {border-color:#9ab08b80}
html[data-palette="sand"] .app-settings-card.tracker-install-card {color:var(--studio-hero-ink)}
html[data-palette="sand"] .app-nav a:focus-visible {outline-color:#f7deb2}
html[data-palette="sand"] :is(.btn-secondary,.app-skip) {--app-ink:#304334;--app-green:#3b6445;--app-focus:#3d6745;color:var(--app-ink)}
@media(prefers-reduced-motion:reduce){html[data-palette] *{transition:none!important;animation:none!important}}