/* ==========================================================
   TomoRing — 主樣式
   設計語言：亮色主題 + LINE綠色 + 玻璃擬態
   ========================================================== */

/* ---------- CSS 自訂屬性 ---------- */
:root {
  --color-bg:          #ffffff;
  --color-bg-alt:      #f8f9fa;
  --color-surface:     rgba(0,0,0,.03);
  --color-surface-h:   rgba(0,0,0,.06);
  --color-border:      rgba(0,0,0,.08);

  --color-primary:     #06c755;
  --color-primary-h:   #05b04b;
  --color-accent:      #04a044;
  --color-accent2:     #3da02b;

  --grad-primary: linear-gradient(135deg, #06c755 0%, #3ebd64 100%);
  --grad-hero:    radial-gradient(ellipse 80% 80% at 50% -20%, rgba(6,199,85,.15) 0%, transparent 70%);

  --color-text:     #1a1d21;
  --color-text-muted: #5e6676;

  --radius-sm:  8px;
  --radius-md:  16px;
  --radius-lg:  24px;
  --radius-xl:  32px;

  --shadow-card: 0 4px 32px rgba(0,0,0,.08);
  --shadow-glow: 0 0 40px rgba(6,199,85,.25);

  --transition: .2s cubic-bezier(.4,0,.2,1);
  --font-sans:  'Inter', 'Noto Sans TC', system-ui, sans-serif;
  --max-w:      1140px;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover { color: var(--color-primary-h); }

img, video { max-width: 100%; display: block; }

code {
  font-family: 'SFMono-Regular', Consolas, monospace;
  font-size: .85em;
  background: rgba(6,199,85,.15);
  color: var(--color-primary-h);
  padding: .15em .45em;
  border-radius: 4px;
}

/* ---------- 容器 ---------- */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: 24px;
}

/* ---------- 通用 Section ---------- */
.section {
  padding-block: 96px;
}
.section--alt {
  background: var(--color-bg-alt);
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}
.section-eyebrow {
  display: inline-block;
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: rgba(6,199,85,.12);
  border: 1px solid rgba(6,199,85,.3);
  padding: .35em 1em;
  border-radius: 999px;
  margin-bottom: 16px;
}
.section-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 16px;
}
.section-desc {
  color: var(--color-text-muted);
  max-width: 560px;
  margin-inline: auto;
  font-size: 1.05rem;
}

/* ---------- 按鈕 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: .7em 1.8em;
  border-radius: 999px;
  font-weight: 600;
  font-size: .95rem;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition);
  border: none;
  white-space: nowrap;
}
.btn--primary {
  background: var(--grad-primary);
  color: #fff;
  box-shadow: 0 4px 20px rgba(6,199,85,.3);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(6,199,85,.45);
  color: #fff;
}
.btn--outline {
  background: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}
.btn--outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary-h);
  background: rgba(6,199,85,.06);
}
.btn--ghost {
  background: transparent;
  color: var(--color-text-muted);
  border: 1.5px solid var(--color-border);
}
.btn--ghost:hover {
  color: var(--color-text);
  border-color: rgba(0,0,0,.2);
  background: var(--color-surface-h);
}

/* gradient text */
.gradient-text {
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ---------- 導覽列 ---------- */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 900;
  padding-block: 16px;
  transition: background var(--transition), box-shadow var(--transition), padding var(--transition);
}
.navbar.scrolled {
  background: rgba(255,255,255,.9);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--color-border);
  padding-block: 10px;
}
.navbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.navbar__logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}
.navbar__logo:hover { color: var(--color-text); }
.logo-icon { font-size: 1.4rem; }
.logo-text { letter-spacing: -.01em; }

.navbar__nav {
  display: flex;
  align-items: center;
  gap: 32px;
}
.navbar__nav a {
  color: var(--color-text-muted);
  font-size: .95rem;
  font-weight: 500;
  transition: color var(--transition);
}
.navbar__nav a:hover { color: var(--color-text); }
.navbar__nav .btn { margin-left: 8px; font-size: .9rem; }

.navbar__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.navbar__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.navbar__hamburger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.navbar__hamburger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.navbar__hamburger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  align-items: center;
  padding-top: 60px;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--grad-hero);
  pointer-events: none;
}

/* 背景光暈 */
.hero__bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
}
.hero__bg-orb--1 {
  width: 600px; height: 600px;
  background: rgba(6,199,85,.15);
  top: -150px; left: -150px;
}
.hero__bg-orb--2 {
  width: 400px; height: 400px;
  background: rgba(62,189,100,.12);
  top: 30%; right: -100px;
}
.hero__bg-orb--3 {
  width: 300px; height: 300px;
  background: rgba(4,160,68,.1);
  bottom: 0; left: 40%;
}

.hero__inner {
  z-index: 1;
  text-align: center;
  padding-top: 20px;
  padding-bottom: 80px;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: clamp(0.75rem, 2vw, 0.85rem);
  font-weight: 500;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  backdrop-filter: blur(8px);
  padding: .45em 1.2em;
  border-radius: 999px;
  margin-bottom: 20px;
}
.badge-dot {
  width: 7px; height: 7px;
  background: var(--color-primary);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(6,199,85,.5); }
  50% { box-shadow: 0 0 0 6px rgba(6,199,85,0); }
}

.hero__title {
  margin-top: 0;
  line-height: 1.15;
  letter-spacing: -.03em;
  margin-bottom: 20px;
}
.hero__title-zh {
  display: block;
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 4px;
}
.hero__title-en {
  display: block;
  font-size: clamp(3.2rem, 11vw, 5.5rem);
  font-weight: 800;
}

.hero__sub {
  font-size: clamp(1rem, 3.5vw, 1.2rem);
  color: var(--color-text-muted);
  max-width: 580px;
  margin-inline: auto;
  margin-bottom: 40px;
  line-height: 1.6;
}
.mobile-break {
  display: none;
}

.hero__actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 64px;
}

.hero__stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  backdrop-filter: blur(16px);
  border-radius: var(--radius-lg);
  padding: 20px 40px;
  width: fit-content;
  margin-inline: auto;
}
.stat-item {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding-inline: 20px;
  width: auto;
  text-align: left;
}
.stat-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  font-size: 1.4rem;
  background: linear-gradient(135deg, rgba(6,199,85,.12), rgba(4,160,68,.05));
  border-radius: 12px;
  border: 1px solid rgba(6,199,85,.2);
  flex-shrink: 0;
}
.stat-text {
  display: flex;
  flex-direction: column;
}
.stat-num {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: 2px;
  letter-spacing: .02em;
}
.stat-num--text {
  font-size: 1.1rem;
}
.stat-label {
  font-size: .8rem;
  color: var(--color-text-muted);
  white-space: nowrap;
  font-weight: 500;
}
.stat-divider {
  width: 1px;
  height: 40px;
  background: var(--color-border);
}

.hero__scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  font-size: .75rem;
  color: var(--color-text-muted);
  animation: fadeInUp 1s ease .5s both;
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateX(-50%) translateY(16px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}
.scroll-arrow {
  width: 20px; height: 20px;
  border-right: 2px solid var(--color-text-muted);
  border-bottom: 2px solid var(--color-text-muted);
  transform: rotate(45deg);
  animation: scrollBounce 1.5s ease-in-out infinite;
}
@keyframes scrollBounce {
  0%,100% { transform: rotate(45deg) translateY(0); }
  50%      { transform: rotate(45deg) translateY(5px); }
}

/* ---------- Features ---------- */
.features__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
  position: relative;
  overflow: hidden;
}
.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(6,199,85,.3);
  box-shadow: var(--shadow-glow);
}

.feature-card--highlight {
  grid-column: span 2;
  background: linear-gradient(135deg, rgba(6,199,85,.08), rgba(4,160,68,.04));
  border-color: rgba(6,199,85,.25);
}
@media (max-width: 700px) {
  .feature-card--highlight { grid-column: span 1; }
}

.feature-card__icon {
  font-size: 2rem;
  margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
}
.feature-card p {
  color: var(--color-text-muted);
  font-size: .95rem;
  line-height: 1.7;
}

/* ---------- How It Works — Steps ---------- */
.steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
  flex-wrap: nowrap;
  margin-bottom: 64px;
}
.step {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
.step__number {
  font-size: .85rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: .08em;
  margin-bottom: 16px;
}
.step__content {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  transition: border-color var(--transition), transform var(--transition);
}
.step__content:hover {
  border-color: rgba(6,199,85,.35);
  transform: translateY(-4px);
}
.step__icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}
.step__content h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 10px;
}
.step__content p {
  color: var(--color-text-muted);
  font-size: .9rem;
  line-height: 1.7;
}
.step__connector {
  flex: 0 0 32px;
  height: 2px;
  background: linear-gradient(90deg, rgba(6,199,85,.5), rgba(4,160,68,.5));
  margin-top: calc(32px + 16px + 32px); /* align with card top center approx */
  align-self: start;
  position: relative;
  top: 96px;
}

/* 架構圖 */
.arch-diagram {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 40px;
  text-align: center;
}
.arch-diagram__title {
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 32px;
}
.arch-diagram__body {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}
.arch-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: rgba(0,0,0,.02);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  min-width: 85px;
  height: 96px;
}
.arch-node--caller { border-color: rgba(6,199,85,.4); }
.arch-node--callee { border-color: rgba(4,160,68,.3); }
.arch-node--more   { border-style: dashed; opacity: .6; }
.arch-node__icon { font-size: 1.6rem; line-height: 1; }
.arch-node__label {
  font-size: .8rem;
  color: var(--color-text-muted);
  text-align: center;
  line-height: 1.4;
}
.arch-node__label small { font-size: .7rem; }

.arch-arrows {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}
.arch-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}
.arch-arrow__label {
  font-size: .7rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}
.arch-arrow__line {
  width: 80px;
  height: 2px;
  background: var(--grad-primary);
  position: relative;
}
.arch-arrow__line::after {
  content: '▶';
  position: absolute;
  right: -2px;
  top: 50%;
  transform: translateY(-50%);
  font-size: .6rem;
  color: var(--color-accent);
}
.arch-server {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  background: linear-gradient(135deg, rgba(6,199,85,.1), rgba(4,160,68,.05));
  border: 1px solid rgba(6,199,85,.3);
  border-radius: var(--radius-md);
  padding: 20px 24px;
}
.arch-server__icon { font-size: 1.8rem; }
.arch-server__label {
  font-size: .85rem;
  font-weight: 600;
  text-align: center;
  line-height: 1.4;
}
.arch-server__label small { font-size: .75rem; color: var(--color-text-muted); font-weight: 400; }
.arch-server__sub {
  font-size: .7rem;
  color: var(--color-text-muted);
  background: rgba(0,0,0,.04);
  padding: 2px 8px;
  border-radius: 4px;
}
.arch-callees {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* ---------- FAQ ---------- */
.faq__list {
  max-width: 760px;
  margin-inline: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition);
}
.faq-item[open] {
  border-color: rgba(6,199,85,.35);
}
.faq-item summary {
  list-style: none;
  padding: 20px 24px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  transition: color var(--transition);
  user-select: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: 1.2rem;
  color: var(--color-primary);
  flex-shrink: 0;
  transition: transform var(--transition);
}
.faq-item[open] summary::after {
  transform: rotate(45deg);
}
.faq-item summary:hover { color: var(--color-primary-h); }
.faq-item__body {
  padding: 0 24px 20px;
  color: var(--color-text-muted);
  font-size: .95rem;
  line-height: 1.75;
}

/* ---------- CTA ---------- */
.cta .container {
  display: flex;
  justify-content: center;
}
.cta__card {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(6,199,85,.08) 0%, rgba(4,160,68,.04) 100%);
  border: 1px solid rgba(6,199,85,.3);
  border-radius: var(--radius-xl);
  padding: 56px 40px; /* Reduced padding from 64px 48px */
  text-align: center;
  width: 100%;
  max-width: 760px;
}
.cta__bg-orb {
  position: absolute;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(6,199,85,.15), transparent 70%);
  top: -100px; left: 50%;
  transform: translateX(-50%);
  pointer-events: none;
}
.cta__content { position: relative; z-index: 1; }
.cta__content h2 {
  font-size: clamp(1.4rem, 3.5vw, 2rem);
  font-weight: 800;
  margin-bottom: 16px;
}
.cta__content p {
  color: var(--color-text-muted);
  font-size: 1rem;
  margin-bottom: 36px;
}
.cta__actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- Footer ---------- */
.footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding-top: 56px;
}
.footer__inner {
  display: flex;
  gap: 48px;
  flex-wrap: wrap;
  padding-bottom: 48px;
}
.footer__brand {
  flex: 1 1 200px;
}
.footer__brand .logo-icon,
.footer__brand .logo-text {
  display: inline;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}
.footer__brand p {
  color: var(--color-text-muted);
  font-size: .9rem;
  margin-top: 8px;
}
.footer__links {
  flex: 2 1 400px;
  display: flex;
  gap: 48px;
  flex-wrap: wrap;
}
.footer__col {
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-width: 120px;
}
.footer__col h4 {
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 4px;
}
.footer__col a {
  font-size: .9rem;
  color: var(--color-text-muted);
  transition: color var(--transition);
  cursor: pointer;
}
.footer__col a:hover { color: var(--color-text); }
.footer__bottom {
  border-top: 1px solid var(--color-border);
  padding-block: 20px;
}
.footer__bottom p {
  font-size: .85rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* ---------- SPA Overlay ---------- */
.spa-overlay {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  align-items: flex-end;
}
.spa-overlay[hidden] { display: none; }

.spa-overlay__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,.7);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  animation: fadeIn .25s ease;
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.spa-overlay__panel {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 760px;
  max-height: 88svh;
  margin-inline: auto;
  background: #ffffff;
  border: 1px solid var(--color-border);
  border-bottom: none;
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  animation: slideUp .3s cubic-bezier(.34,1.56,.64,1);
}
@media (min-width: 600px) {
  .spa-overlay {
    align-items: center;
  }
  .spa-overlay__panel {
    border-bottom: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    max-height: 80svh;
    animation: modalIn .3s cubic-bezier(.34,1.56,.64,1);
  }
}
@keyframes slideUp {
  from { transform: translateY(100%); }
  to   { transform: translateY(0); }
}
@keyframes modalIn {
  from { transform: scale(.95) translateY(20px); opacity: 0; }
  to   { transform: scale(1) translateY(0);       opacity: 1; }
}

.spa-overlay__close {
  position: absolute;
  top: 16px; right: 20px;
  width: 34px; height: 34px;
  display: flex; align-items: center; justify-content: center;
  background: rgba(0,0,0,.06);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-muted);
  font-size: .9rem;
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
  z-index: 2;
}
.spa-overlay__close:hover {
  background: rgba(0,0,0,.12);
  color: var(--color-text);
}

.spa-overlay__content {
  padding: 28px 32px 40px;
  overflow-y: auto;
  flex: 1;
  overscroll-behavior: contain;
}

/* SPA 頁面內部排版 */
.spa-page h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 24px;
  padding-right: 40px;
}
.spa-page h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-top: 28px;
  margin-bottom: 10px;
  color: var(--color-primary-h);
}
.spa-page p, .spa-page li {
  color: var(--color-text-muted);
  font-size: .95rem;
  line-height: 1.8;
  margin-bottom: 12px;
}
.spa-page ul, .spa-page ol {
  padding-left: 1.5em;
  margin-bottom: 16px;
}
.spa-page .spa-date {
  font-size: .8rem;
  color: var(--color-text-muted);
  margin-bottom: 28px;
  display: block;
}
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
  margin-top: 16px;
}
.team-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: center;
}
.team-card__avatar {
  width: 56px; height: 56px;
  border-radius: 50%;
  background: var(--grad-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin: 0 auto 12px;
}
.team-card__name {
  font-weight: 700;
  font-size: .95rem;
  margin-bottom: 4px;
}
.team-card__role {
  font-size: .8rem;
  color: var(--color-text-muted);
}

/* Loading spinner */
.spinner {
  width: 36px; height: 36px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin .7s linear infinite;
  margin: 60px auto;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ---------- 行動裝置 ---------- */
@media (max-width: 768px) {
  .navbar__nav {
    position: fixed;
    top: 0; right: 0;
    width: min(320px, 90vw);
    height: 100svh;
    background: rgba(255,255,255,.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: flex-start;
    padding: 80px 32px 32px;
    gap: 24px;
    transform: translateX(100%);
    transition: transform .3s cubic-bezier(.4,0,.2,1);
    z-index: 800;
    border-left: 1px solid var(--color-border);
  }
  .navbar__nav.is-open {
    transform: translateX(0);
  }
  .navbar__nav a { font-size: 1.1rem; }
  .navbar__hamburger { display: flex; z-index: 850; }

  .steps {
    flex-direction: column;
    align-items: center;
    gap: 16px;
  }
  .step { max-width: 400px; width: 100%; }
  .step__connector {
    display: none;
  }

  .hero {
    display: block;
    align-items: stretch;
    padding-top: 0;
  }
  .hero__inner {
    padding-top: 0;
    padding-bottom: 64px;
  }
  .hero__main-fold {
    min-height: 100svh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
    padding-top: 60px;
  }
  .mobile-break {
    display: block;
  }
  .hero__actions {
    margin-bottom: 0;
  }

  .hero__stats {
    flex-direction: column;
    align-items: flex-start;
    padding: 24px 32px;
    gap: 0;
    width: 100%;
    margin-top: 24px;
  }
  .stat-item { padding-block: 16px; justify-content: flex-start; }
  .stat-divider { width: 100%; height: 1px; }

  .arch-diagram {
    display: none;
  }
  .arch-diagram__body {
    flex-direction: column;
    gap: 12px;
  }
  .arch-arrow__line { width: 2px; height: 40px; }
  .arch-arrow__line::after { transform: rotate(90deg) translateX(50%); right: auto; top: auto; bottom: -4px; left: 50%; }
  .arch-callees { flex-direction: row; }

  .section { padding-block: 64px; }
  .cta__card { padding: 40px 24px; }
  .spa-overlay__content { padding: 20px 20px 32px; }
}

@media (max-width: 480px) {
  .features__grid { grid-template-columns: 1fr; }
  .feature-card--highlight { grid-column: span 1; }
  .hero__actions { flex-direction: column; align-items: center; }
  .cta__actions { flex-direction: column; align-items: center; }
}

/* ---------- 無障礙：鍵盤焦點 ---------- */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 捲動動畫（IntersectionObserver） ---------- */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .6s ease, transform .6s ease;
}
.animate-on-scroll.is-visible {
  opacity: 1;
  transform: translateY(0);
}