/* ==========================================================================
   ds-components.css — Phase 2: buttons and navigation.
   Requires ds.css. Everything is scoped under .ds so it cannot leak into the
   86 pages that load tokens.css.

   Brief 100: every button has idle / hover / focus / pressed / loading /
   success / error / disabled. No browser defaults are left anywhere.
   ========================================================================== */

/* ==========================================================================
   BUTTONS
   ========================================================================== */

.ds .btn {
  --btn-h: 44px;
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s-2);
  height: var(--btn-h);
  padding: 0 var(--s-5);
  border: 1px solid transparent;
  border-radius: var(--r-button);
  font-family: inherit;
  font-size: var(--fs-body);
  font-weight: var(--fw-semi);
  line-height: 1;
  letter-spacing: -.01em;
  white-space: nowrap;
  cursor: pointer;
  text-decoration: none;
  isolation: isolate;
  -webkit-tap-highlight-color: transparent;
  transition:
    transform var(--t-fast) var(--ease-out),
    background-color var(--t-fast) var(--ease-inout),
    border-color var(--t-fast) var(--ease-inout),
    color var(--t-fast) var(--ease-inout),
    box-shadow var(--t-normal) var(--ease-out);
}

/* Sizes. 50px matches brief 15's 48-52px for the primary hero action. */
.ds .btn-lg { --btn-h: 50px; padding: 0 var(--s-6); font-size: var(--fs-body-l); }
.ds .btn-sm { --btn-h: 36px; padding: 0 var(--s-4); font-size: var(--fs-label); }

/* Press: scale 0.98, then spring back on release (brief 15). */
.ds .btn:active:not(:disabled):not([data-state]) { transform: scale(.98); transition-duration: 80ms; }

/* ---- Primary -------------------------------------------------------- */
.ds .btn-primary {
  background: var(--c-green);
  color: var(--c-on-green);
  /* Subtle inner highlight + soft bottom shadow, not a glow. */
  box-shadow: inset 0 1px 0 rgba(255,255,255,.16), var(--e-green);
}
.ds .btn-primary:hover:not(:disabled):not([data-state]) {
  background: var(--c-green-hover);
  transform: translateY(-1px);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.18), 0 8px 22px -8px rgba(14,124,63,.55);
}
.ds .btn-primary:active:not(:disabled):not([data-state]) { background: var(--c-green-press); }

/* ---- Secondary ------------------------------------------------------- */
.ds .btn-secondary {
  background: var(--c-surface);
  color: var(--c-ink);
  border-color: var(--c-line-2);
  box-shadow: var(--e-control);
}
.ds .btn-secondary:hover:not(:disabled):not([data-state]) {
  border-color: var(--c-line-strong);
  transform: translateY(-1px);
  box-shadow: var(--e-card);
}

/* ---- Ghost ----------------------------------------------------------- */
.ds .btn-ghost { background: transparent; color: var(--c-ink); }
.ds .btn-ghost:hover:not(:disabled):not([data-state]) { background: var(--c-bg-sunk); }

/* ---- Text ------------------------------------------------------------ */
.ds .btn-text {
  background: none; color: var(--c-green-text); height: auto;
  padding: var(--s-1) var(--s-2); font-weight: var(--fw-semi);
}
.ds .btn-text:hover:not(:disabled) { text-decoration: underline; text-underline-offset: 3px; }

/* ---- Danger ---------------------------------------------------------- */
.ds .btn-danger { background: var(--c-danger); color: var(--c-on-danger); }
.ds .btn-danger:hover:not(:disabled):not([data-state]) { filter: brightness(.94); transform: translateY(-1px); }

/* ---- Icon-only ------------------------------------------------------- */
.ds .btn-icon {
  width: var(--btn-h); padding: 0; border-radius: var(--r-control);
  background: var(--c-surface); border-color: var(--c-line-2); color: var(--c-ink-2);
}
.ds .btn-icon:hover:not(:disabled) { color: var(--c-ink); border-color: var(--c-line-strong); }

/* ---- Disabled -------------------------------------------------------- */
.ds .btn:disabled,
.ds .btn[aria-disabled="true"] {
  cursor: not-allowed; opacity: .45; box-shadow: none; transform: none;
  /* Disabled must still be readable: opacity alone can drop below AA, so the
     primary keeps a solid fill rather than fading into the page. */
}
.ds .btn-primary:disabled { background: var(--c-ink-faint); color: #fff; opacity: .6; }

/* ---- Loading (brief 101): width must not jump ------------------------ */
.ds .btn[data-state="loading"] { cursor: progress; pointer-events: none; }
.ds .btn[data-state="loading"] .btn-label { opacity: .85; }
/* Tiny row segments moving inside the icon slot — the product's own metaphor,
   not a generic spinner. */
.ds .btn-rows { display: inline-flex; flex-direction: column; gap: 2px; width: 14px; }
.ds .btn-rows i { display: block; height: 2px; border-radius: 1px; background: currentColor; opacity: .45; }
.ds .btn-rows i:nth-child(1) { width: 100%; }
.ds .btn-rows i:nth-child(2) { width: 64%; }
.ds .btn-rows i:nth-child(3) { width: 82%; }
.ds .btn[data-state="loading"] .btn-rows i { animation: btnRows 1.05s var(--ease-inout) infinite; }
.ds .btn[data-state="loading"] .btn-rows i:nth-child(2) { animation-delay: .12s; }
.ds .btn[data-state="loading"] .btn-rows i:nth-child(3) { animation-delay: .24s; }
@keyframes btnRows {
  0%, 100% { opacity: .3; transform: translateX(0); }
  50%      { opacity: 1;  transform: translateX(2px); }
}

/* ---- Success --------------------------------------------------------- */
.ds .btn[data-state="success"] { background: var(--c-green); color: var(--c-on-green); pointer-events: none; }
.ds .btn-secondary[data-state="success"],
.ds .btn-ghost[data-state="success"] {
  background: var(--c-green-soft); color: var(--c-green-text); border-color: var(--c-green-line);
}

/* ---- Error ----------------------------------------------------------- */
.ds .btn[data-state="error"] { background: var(--c-danger); color: var(--c-on-danger); }
/* Brief 102: a small nudge, never an aggressive shake. */
.ds .btn[data-state="error"] { animation: nudge .32s var(--ease-out); }
@keyframes nudge {
  0%,100% { transform: translateX(0); }
  25%     { transform: translateX(-3px); }
  75%     { transform: translateX(3px); }
}

/* ---- Icon motion on interaction only (brief 17) ---------------------- */
.ds .btn .ico { display: inline-flex; transition: transform var(--t-normal) var(--ease-out); }
.ds .btn:hover:not(:disabled):not([data-state]) .ico-arrow    { transform: translateX(3px); }
.ds .btn:hover:not(:disabled):not([data-state]) .ico-upload   { transform: translateY(-2px); }
.ds .btn:hover:not(:disabled):not([data-state]) .ico-download { transform: translateY(2px); }

/* ==========================================================================
   NAVIGATION (brief 18, 19)
   ========================================================================== */

.ds .nav {
  position: sticky; top: 0; z-index: 60;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: height var(--t-normal) var(--ease-inout),
              background-color var(--t-normal) var(--ease-inout),
              border-color var(--t-normal) var(--ease-inout),
              backdrop-filter var(--t-normal) var(--ease-inout);
}
.ds .nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--s-6); height: 72px;
  transition: height var(--t-normal) var(--ease-inout);
}
/* Compressed state, toggled by ds-motion.js on scroll. */
.ds .nav.is-scrolled {
  background: rgba(255,255,255,.88);
  backdrop-filter: blur(14px) saturate(150%);
  -webkit-backdrop-filter: blur(14px) saturate(150%);
  border-bottom-color: var(--c-line);
}
.ds .nav.is-scrolled .nav-inner { height: 60px; }

.ds .nav-links { display: flex; align-items: center; gap: var(--s-5); list-style: none; margin: 0; padding: 0; }
.ds .nav-links a {
  position: relative; display: inline-block; padding: var(--s-2) 0;
  color: var(--c-ink-2); font-size: 15px; font-weight: var(--fw-medium);
  text-decoration: none; transition: color var(--t-fast) var(--ease-inout);
}
.ds .nav-links a:hover { color: var(--c-ink); }
/* Brief 19: a data-line growing from the centre, not a colour swap. */
.ds .nav-links a::after {
  content: ""; position: absolute; left: 50%; right: 50%; bottom: 0; height: 2px;
  border-radius: 2px; background: var(--c-green);
  transition: left 180ms var(--ease-out), right 180ms var(--ease-out);
}
.ds .nav-links a:hover::after,
.ds .nav-links a[aria-current="page"]::after { left: 0; right: 0; }

.ds .nav-cta { display: flex; align-items: center; gap: var(--s-3); }

/* Dropdowns — restrained (brief 19). */
.ds .nav-menu {
  position: absolute; top: calc(100% + 8px); left: 0; min-width: 220px;
  background: var(--c-surface); border: 1px solid var(--c-line);
  border-radius: var(--r-card); box-shadow: var(--e-float);
  padding: var(--s-2);
  opacity: 0; transform: translateY(6px) scale(.98); pointer-events: none;
  transition: opacity var(--t-fast) var(--ease-inout),
              transform var(--t-fast) var(--ease-inout);
}
.ds .nav-item[data-open="true"] .nav-menu { opacity: 1; transform: none; pointer-events: auto; }
.ds .nav-menu a {
  display: block; padding: var(--s-3); border-radius: var(--r-control);
  color: var(--c-ink-2); font-size: 14.5px; text-decoration: none;
}
.ds .nav-menu a:hover { background: var(--c-bg-sunk); color: var(--c-ink); }

/* ==========================================================================
   MOTION PRIMITIVE STYLES (paired with ds-motion.js)
   ========================================================================== */

.ds [data-reveal] { opacity: 0; transform: translateY(12px); }
.ds [data-reveal].is-in {
  opacity: 1; transform: none;
  transition: opacity var(--t-slow) var(--ease-out), transform var(--t-slow) var(--ease-out);
}

.ds [data-mask] { overflow: hidden; }
.ds [data-mask] > * { display: block; transform: translateY(100%); }
.ds [data-mask].is-in > * {
  transform: none;
  transition: transform var(--t-slow) var(--ease-out);
}

/* Shared selection indicator (segmented controls). */
.ds .seg { position: relative; display: inline-flex; gap: 2px; padding: 4px;
  background: var(--c-bg-sunk); border-radius: var(--r-control); }
.ds .seg-ind {
  position: absolute; top: 4px; bottom: 4px; left: 0; width: 0;
  background: var(--c-surface); border-radius: 8px; box-shadow: var(--e-control);
  transition: transform var(--t-normal) var(--ease-out), width var(--t-normal) var(--ease-out);
  pointer-events: none;
}
.ds .seg button {
  position: relative; z-index: 1; border: 0; background: none; cursor: pointer;
  padding: var(--s-2) var(--s-4); border-radius: 8px;
  font: inherit; font-size: var(--fs-label); font-weight: var(--fw-semi);
  color: var(--c-ink-3); transition: color var(--t-fast) var(--ease-inout);
}
.ds .seg button[aria-selected="true"] { color: var(--c-ink); }

/* Animated check (brief 55) — stroke draws, ~400ms, no confetti. */
.ds .check circle, .ds .check path { stroke-dasharray: var(--len); stroke-dashoffset: var(--len); }
.ds .check.is-in circle { animation: drawStroke .34s var(--ease-out) forwards; }
.ds .check.is-in path   { animation: drawStroke .26s var(--ease-out) .22s forwards; }
@keyframes drawStroke { to { stroke-dashoffset: 0; } }

@media (prefers-reduced-motion: reduce) {
  .ds [data-reveal], .ds [data-mask] > * { opacity: 1; transform: none; }
  .ds .check circle, .ds .check path { stroke-dashoffset: 0; animation: none; }
  .ds .btn[data-state="error"] { animation: none; }
}