:root {
  --sfsf-theme: #0ea5b7;            /* 預設主題：藍綠 */
  --sfsf-accent: #06b6d4;           /* 科技藍綠點綴 */
  --sfsf-accent-2: #14b8a6;         /* 青綠 */
  --sfsf-ink: #0b2b33;              /* 深墨綠文字 */
  --sfsf-text: #12303a;
  --sfsf-muted: #5b7a86;
  --sfsf-border: #cfe6ea;           /* 框線：淡藍綠 */
  --sfsf-border-strong: #7fd0da;    /* 節點框線：較深藍綠 */
  --sfsf-surface: #ffffff;
  --sfsf-surface-soft: #f2fbfc;     /* 淺藍綠底 */
  --sfsf-grid: rgba(14, 165, 183, .06);
  --sfsf-shadow: 0 18px 40px rgba(6, 95, 108, .16);
  --sfsf-shadow-soft: 0 10px 30px rgba(10, 90, 104, .10);
  --sfsf-radius: 18px;
  --sfsf-radius-node: 10px;
  --sfsf-font: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, sans-serif;
}

* { box-sizing: border-box; }

.sfsf-shortcode {
  width: 100%;
  font-family: var(--sfsf-font);
  color: var(--sfsf-text);
}

/* ---------- Header ---------- */
.sfsf-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.sfsf-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin: 0 0 6px;
  padding: 3px 11px 3px 9px;
  border-radius: 999px;
  background: linear-gradient(135deg, rgba(6,182,212,.14), rgba(20,184,166,.14));
  color: #0e7d8c;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .02em;
}

.sfsf-eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--sfsf-accent), var(--sfsf-accent-2));
  box-shadow: 0 0 0 3px rgba(6,182,212,.18);
}

.sfsf-header h2 {
  margin: 0;
  color: var(--sfsf-ink);
  font-size: clamp(23px, 3vw, 33px);
  font-weight: 800;
  letter-spacing: .01em;
}

.sfsf-reset {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 40px;
  padding: 0 18px;
  border: 1px solid var(--sfsf-border);
  border-radius: 999px;
  background: var(--sfsf-surface);
  color: #0e7d8c;
  font-family: inherit;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: background .18s ease, border-color .18s ease, transform .12s ease, box-shadow .18s ease;
}

.sfsf-reset:hover {
  background: var(--sfsf-surface-soft);
  border-color: var(--sfsf-accent);
  box-shadow: 0 6px 16px rgba(6,182,212,.16);
}

.sfsf-reset:active { transform: translateY(1px); }

/* ---------- Canvas ---------- */
.system-flow {
  --sfsf-theme: #0ea5b7;
  position: relative;
  width: 100%;
  min-height: 520px;
  overflow: auto;
  border: 1px solid var(--sfsf-border);
  border-radius: var(--sfsf-radius);
  background:
    radial-gradient(120% 120% at 0% 0%, rgba(6,182,212,.06), transparent 42%),
    radial-gradient(120% 120% at 100% 100%, rgba(20,184,166,.06), transparent 42%),
    linear-gradient(var(--sfsf-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--sfsf-grid) 1px, transparent 1px),
    #fbfeff;
  background-size: auto, auto, 24px 24px, 24px 24px;
  box-shadow: var(--sfsf-shadow-soft);
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: #9fd7df transparent;
}

.system-flow::-webkit-scrollbar { width: 11px; height: 11px; }
.system-flow::-webkit-scrollbar-thumb {
  border: 3px solid transparent;
  border-radius: 999px;
  background: #a7dbe2;
  background-clip: content-box;
}
.system-flow::-webkit-scrollbar-thumb:hover {
  background: #79c8d2;
  background-clip: content-box;
}
.system-flow::-webkit-scrollbar-track { background: transparent; }

.sfsf-stage {
  position: relative;
  min-width: 900px;
  min-height: 520px;
}

.sfsf-edges {
  position: absolute;
  inset: 0;
  z-index: 1;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: none;
}

/* ---------- Nodes ---------- */
.sfsf-node {
  position: absolute;
  z-index: 2;
  width: 156px;
  height: var(--node-height, 32px);
}

/* 開啟選單的節點提到最上層，避免被相鄰節點蓋住 */
.sfsf-node.is-open { z-index: 60; }

.sfsf-button {
  position: relative;
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 4px 13px;
  border: 1px solid var(--node-border, var(--sfsf-theme));
  border-radius: var(--node-radius, var(--sfsf-radius-node));
  background: var(--node-bg, #fff);
  color: var(--node-color, var(--sfsf-ink));
  font: inherit;
  font-size: var(--node-font-size, 14px);
  font-weight: 700;
  line-height: 1.3;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  box-shadow: 0 1px 2px rgba(9,80,92,.06), 0 4px 10px rgba(9,80,92,.05);
  cursor: pointer;
  transition: transform .14s ease, box-shadow .18s ease, border-color .18s ease, filter .18s ease;
}

button.sfsf-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(9,80,92,.12), 0 12px 22px rgba(9,80,92,.14);
  filter: brightness(1.02);
}

button.sfsf-button:active { transform: translateY(0); }

button.sfsf-button:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(6,182,212,.35), 0 8px 18px rgba(9,80,92,.14);
}

/* 有下拉選單時，右側保留 chevron 空間 */
.sfsf-node.has-menu .sfsf-button { padding-right: 28px; }

.sfsf-node--tag {
  width: auto !important;
  white-space: nowrap;
}

/* 純文字標題：透明底、只有文字 */
.sfsf-node--tag .sfsf-button {
  justify-content: flex-start;
  padding: 0;
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  overflow: visible;
  color: var(--node-color, var(--sfsf-ink));
  font-weight: 800;
  letter-spacing: .01em;
  transition: none;
}

.sfsf-node--tag .sfsf-button:hover { transform: none; }

/* 色塊標題：保留底色、置中、加內距與圓角 */
.sfsf-node--tag.is-filled {
  width: auto !important;
}

.sfsf-node--tag.is-filled .sfsf-button {
  justify-content: center;
  padding: 5px 16px;
  border-radius: var(--node-radius, var(--sfsf-radius-node));
  background: var(--node-bg, var(--sfsf-theme));
  color: var(--node-color, #fff);
  box-shadow: 0 2px 6px rgba(9, 80, 92, .14);
  overflow: visible;
}

.sfsf-node--divider .sfsf-button {
  height: 2px;
  min-height: 2px;
  padding: 0;
  border: 0;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--node-color, var(--sfsf-accent)), transparent);
  font-size: 0;
}

/* 尚未對應文章的節點：不可點、灰化 */
.sfsf-node.is-disabled .sfsf-button {
  cursor: default;
  opacity: .55;
  filter: grayscale(.35);
  box-shadow: none;
}

.sfsf-node.is-disabled .sfsf-button:hover {
  transform: none;
  box-shadow: none;
  filter: grayscale(.35);
}

.sfsf-node.is-disabled .sfsf-chevron {
  opacity: .3;
}

/* 「準備中」提示（滑鼠移上淡入） */
.sfsf-node.is-disabled[data-tip]::after {
  content: attr(data-tip);
  position: absolute;
  bottom: calc(100% + 7px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  z-index: 65;
  padding: 5px 10px;
  border-radius: 8px;
  background: rgba(11, 43, 51, .95);
  color: #eafcff;
  font-size: 12px;
  font-weight: 600;
  line-height: 1;
  white-space: nowrap;
  letter-spacing: .02em;
  box-shadow: 0 6px 16px rgba(6, 60, 70, .3);
  opacity: 0;
  pointer-events: none;
  transition: opacity .16s ease, transform .16s ease;
}

/* 小三角 */
.sfsf-node.is-disabled[data-tip]::before {
  content: "";
  position: absolute;
  bottom: calc(100% + 3px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  z-index: 65;
  border: 5px solid transparent;
  border-top-color: rgba(11, 43, 51, .95);
  opacity: 0;
  pointer-events: none;
  transition: opacity .16s ease, transform .16s ease;
}

.sfsf-node.is-disabled[data-tip]:hover::after,
.sfsf-node.is-disabled[data-tip]:hover::before {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* 選單內尚未對應文章的項目 */
.sfsf-menu a.is-disabled {
  cursor: default;
  color: #9db4bc;
}

.sfsf-menu a.is-disabled::before {
  opacity: .25;
}

.sfsf-menu a.is-disabled:hover {
  background: transparent;
  color: #9db4bc;
}

.sfsf-menu a.is-disabled:hover::before {
  opacity: .25;
  transform: none;
}

/* ---------- Chevron ---------- */
.sfsf-chevron {
  position: absolute;
  right: 11px;
  top: 50%;
  width: 7px;
  height: 7px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  border-radius: 1px;
  transform: translateY(-65%) rotate(45deg);
  transition: transform .2s ease;
  opacity: .75;
}

.sfsf-node.is-open .sfsf-chevron {
  transform: translateY(-35%) rotate(225deg);
  opacity: 1;
}

/* ---------- Menu ---------- */
.sfsf-menu {
  position: absolute;
  z-index: 61;
  top: calc(100% + 8px);
  left: 0;
  width: max(232px, 100%);
  max-height: 300px;
  overflow-y: auto;
  padding: 8px;
  border: 1px solid var(--sfsf-border);
  border-radius: 14px;
  background: rgba(255,255,255,.98);
  backdrop-filter: blur(8px);
  box-shadow: var(--sfsf-shadow);
  scrollbar-width: thin;
  scrollbar-color: #a7dbe2 transparent;
  animation: sfsf-pop .16s ease;
}

/* 選單小箭嘴 */
.sfsf-menu::before {
  content: "";
  position: absolute;
  top: -6px;
  left: 22px;
  width: 12px;
  height: 12px;
  background: inherit;
  border-left: 1px solid var(--sfsf-border);
  border-top: 1px solid var(--sfsf-border);
  transform: rotate(45deg);
}

@keyframes sfsf-pop {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes sfsf-pop-up {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* 空間不足時往上開 */
.sfsf-menu.is-flip-up {
  top: auto;
  bottom: calc(100% + 8px);
  animation: sfsf-pop-up .16s ease;
}
.sfsf-menu.is-flip-up::before {
  top: auto;
  bottom: -6px;
  border-left: 0;
  border-top: 0;
  border-right: 1px solid var(--sfsf-border);
  border-bottom: 1px solid var(--sfsf-border);
}

/* 空間不足時靠右對齊（往左開） */
.sfsf-menu.is-flip-left {
  left: auto;
  right: 0;
}
.sfsf-menu.is-flip-left::before {
  left: auto;
  right: 22px;
}

.sfsf-menu[hidden] { display: none; }

.sfsf-menu::-webkit-scrollbar { width: 8px; }
.sfsf-menu::-webkit-scrollbar-thumb {
  border: 2px solid transparent;
  border-radius: 999px;
  background: #bfe4ea;
  background-clip: content-box;
}

.sfsf-menu a {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border-radius: 9px;
  color: #16414c;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.4;
  text-decoration: none;
  transition: background .15s ease, color .15s ease, padding-left .15s ease;
}

.sfsf-menu a::before {
  content: "";
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--sfsf-accent), var(--sfsf-accent-2));
  opacity: .5;
  transition: opacity .15s ease, transform .15s ease;
}

.sfsf-menu a:hover,
.sfsf-menu a:focus-visible {
  background: linear-gradient(135deg, rgba(6,182,212,.12), rgba(20,184,166,.12));
  color: #0b6d7c;
  outline: none;
}

.sfsf-menu a:hover::before,
.sfsf-menu a:focus-visible::before {
  opacity: 1;
  transform: scale(1.25);
}

/* ---------- Toast ---------- */
.sfsf-toast {
  position: sticky;
  z-index: 70;
  left: 16px;
  bottom: 16px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  max-width: calc(100% - 32px);
  padding: 10px 15px;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(8,42,50,.94), rgba(12,74,86,.94));
  color: #eafcff;
  font-size: 13px;
  font-weight: 600;
  box-shadow: 0 12px 30px rgba(6,60,70,.35);
  opacity: 0;
  transform: translateY(10px);
  transition: opacity .22s ease, transform .22s ease;
  pointer-events: none;
}

.sfsf-toast::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--sfsf-accent);
  box-shadow: 0 0 0 3px rgba(6,182,212,.3);
}

.sfsf-toast.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Zoom controls ---------- */
.sfsf-zoom {
  position: sticky;
  top: 14px;
  left: 100%;
  z-index: 50;
  display: inline-flex;
  gap: 3px;
  margin: 14px 14px 0 0;
  padding: 5px;
  border: 1px solid var(--sfsf-border);
  border-radius: 14px;
  background: rgba(255,255,255,.9);
  box-shadow: var(--sfsf-shadow-soft);
  backdrop-filter: blur(8px);
  width: max-content;
  float: right;
}

.sfsf-zoom button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 0;
  border-radius: 9px;
  background: transparent;
  color: #0e7d8c;
  font-family: inherit;
  font-size: 17px;
  font-weight: 800;
  line-height: 1;
  cursor: pointer;
  transition: background .15s ease, color .15s ease, transform .1s ease;
}

.sfsf-zoom button:hover {
  background: linear-gradient(135deg, rgba(6,182,212,.14), rgba(20,184,166,.14));
  color: #0b6d7c;
}

.sfsf-zoom button:active { transform: scale(.92); }

/* ---------- Error ---------- */
.sfsf-error {
  padding: 16px 18px;
  border: 1px solid #f4c2b6;
  border-radius: 12px;
  background: #fff6f3;
  color: #b23a1b;
  font-weight: 600;
}

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
  .sfsf-header {
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
  }
  .sfsf-reset { min-height: 36px; }
  .system-flow { min-height: 420px; border-radius: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  .sfsf-button, .sfsf-reset, .sfsf-menu, .sfsf-menu a, .sfsf-toast, .sfsf-zoom button, .sfsf-chevron {
    transition: none !important;
    animation: none !important;
  }
}