* {
        -webkit-tap-highlight-color: transparent;
      }

      :root {
        --base-font-size: 18px;
        --heading-font-family: system-ui, -apple-system, BlinkMacSystemFont,
          "Segoe UI", sans-serif;
        --body-font-family: system-ui, -apple-system, BlinkMacSystemFont,
          "Segoe UI", sans-serif;
        --title-color: #2b2560;
        --body-color: #333333;
        --bg-blur: 3px;
        --bg-dim: 0.2;
        --bg-brightness: 1;
        --ui-opacity: 0.25;
        --block-bg-color: rgba(10, 12, 30, var(--ui-opacity));
        --button-bg-color: rgba(10, 12, 30, var(--ui-opacity));
        --bg-blur-soft: calc(var(--bg-blur) * 0.5);
        --header-bg-color: rgba(5, 7, 20, var(--ui-opacity));
        --card-bg: rgba(255, 255, 255, 0.08);
        --card-border: rgba(255, 255, 255, 0.25);
        --accent: #6b5bff;
        --accent-soft: rgba(107, 91, 255, 0.12);
        --nav-bg: rgba(20, 16, 60, 0.96);
        --nav-border: rgba(255, 255, 255, 0.16);
        --surface-glass: rgba(10, 12, 30, 0.16);
        --surface-strong: rgba(10, 12, 30, 0.24);
        --surface-border: rgba(255, 255, 255, 0.24);
        --surface-dark: rgba(5, 7, 18, 0.35);
        --surface-button: rgba(255, 255, 255, 0.14);
      }

      html,
      body {
        margin: 0;
        padding: 0;
        height: 100%;
        font-size: var(--base-font-size);
        font-family: var(--body-font-family);
        color: var(--body-color);
        background-color: transparent;
        overflow-x: hidden;
      }

      body {
        min-height: 100vh;
        background-size: cover;
        background-repeat: no-repeat;
        background-position: center;
        background-attachment: fixed;
        position: relative;
        overflow-y: auto;
        scrollbar-width: none; /* Firefox */
        -ms-overflow-style: none; /* IE 10+ */
        -webkit-user-select: none;
        user-select: none;
        -webkit-touch-callout: none;
      }

      html::-webkit-scrollbar,
      body::-webkit-scrollbar {
        display: none; /* Chrome/Safari */
      }

      input,
      textarea,
      select,
      option {
        -webkit-user-select: text;
        user-select: text;
        -webkit-touch-callout: default;
      }

      body::-webkit-scrollbar {
        display: none; /* Chrome/Safari */
      }

      body::before {
        content: "";
        position: fixed;
        inset: 0;
        background: rgba(0, 0, 0, var(--bg-dim));
        backdrop-filter: blur(var(--bg-blur-soft)) brightness(var(--bg-brightness));
        pointer-events: none;
        z-index: 0;
      }

      body.theme-tech {
        background-image: url("/assets/backgrounds/citynightview/city_taiwan_taipei101.jpg");
      }

      body.theme-story {
        background-image: url("/assets/backgrounds/story_bg.jpg");
      }

      body.theme-nature-tw-1 {
        background-image: url("/assets/backgrounds/greatriver/river_china_yangtzeriver.jpg");
      }

      body.theme-taipei101 {
        background-image: url("/assets/backgrounds/citynightview/city_taiwan_taipei101.jpg");
      }

      body.theme-art-tw-1 {
        background-image: url("/assets/backgrounds/greatriver/river_china_yangtzeriver.jpg");
      }

      body.theme-river-yangtze {
        background-image: url("/assets/backgrounds/greatriver/river_china_yangtzeriver.jpg");
      }

      body.theme-river-amazon {
        background-image: url("/assets/backgrounds/greatriver/river_brazil_amazonriver.jpg");
      }

      body.theme-river-nile {
        background-image: url("/assets/backgrounds/greatriver/river_egypt_nileriver.jpg");
      }

      body.theme-river-ganges {
        background-image: url("/assets/backgrounds/greatriver/river_india_gangesriver.jpg");
      }

      body.theme-river-danube {
        background-image: url("/assets/backgrounds/greatriver/river_europe_danuberiver.jpg");
      }

      body.theme-river-mississippi {
        background-image: url("/assets/backgrounds/greatriver/river_us_mississippiriver.jpg");
      }

      body.theme-ab-polarbear {
        background-image: url("/assets/backgrounds/aurora/a_borealispolarbear.jpg");
      }

      body.theme-ab-arcticfox {
        background-image: url("/assets/backgrounds/aurora/a_borealisarcticfox.jpg");
      }

      body.theme-ab-seal {
        background-image: url("/assets/backgrounds/aurora/a_borealisseal.jpg");
      }

      body.theme-ab-arcticglaciers {
        background-image: url("/assets/backgrounds/aurora/a_arcticglaciers.jpg");
      }

      body.theme-ab-arcticreindeer {
        background-image: url("/assets/backgrounds/aurora/a_arcticreindeer.jpg");
      }

      body.theme-ab-antarcticpenguins {
        background-image: url("/assets/backgrounds/aurora/b_antarcticpenguins.jpg");
      }

      body.theme-ab-antarctichumpbackwhale {
        background-image: url("/assets/backgrounds/aurora/b_antarctichumpbackwhale.jpg");
      }

      body.theme-ab-antarcticbirds {
        background-image: url("/assets/backgrounds/aurora/b_antarcticbirds.jpg");
      }

      body.theme-ab-antarctickrill {
        background-image: url("/assets/backgrounds/aurora/b_antarctickrill.jpg");
      }

      body.theme-ab-antarcticicebergs {
        background-image: url("/assets/backgrounds/aurora/b_antarcticicebergs.jpg");
      }

      body.theme-hongkong-night {
        background-image: url("/assets/backgrounds/citynightview/city_hongkong.jpg");
      }

      body.theme-seoul-night {
        background-image: url("/assets/backgrounds/citynightview/city_southkorea_seoul.jpg");
      }

      body.theme-newyork-moon {
        background-image: url("/assets/backgrounds/citynightview/city_us_newyork.jpg");
      }

      body.theme-london-moon {
        background-image: url("/assets/backgrounds/citynightview/city_england_london.jpg");
      }

      body.theme-singapore-night {
        background-image: url("/assets/backgrounds/citynightview/city_singapore.jpg");
      }

      body.theme-kuala-lumpur-night {
        background-image: url("/assets/backgrounds/citynightview/city_malaysia_kualalumpur.jpg");
      }

      body.theme-sydney-night {
        background-image: url("/assets/backgrounds/citynightview/city_australia_sydney.jpg");
      }

      body.theme-sunrise-yushan {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_taiwan_yushan.jpg");
      }

      body.theme-sunrise-huangshan {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_china_huangshan.jpg");
      }

      body.theme-sunrise-taimoshan {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_hongkong_taimoshan.jpg");
      }

      body.theme-sunrise-mountfuji {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_japan_mountfuji.jpg");
      }

      body.theme-sunrise-mountfaber {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_singapore_mountfaber.jpg");
      }

      body.theme-sunrise-mountkinabalu {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_malaysia_mountkinabalu.jpg");
      }

      body.theme-sunrise-uluru {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_australia_uluru.jpg");
      }

      body.theme-sunrise-helveryn {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_england_helveryn.jpg");
      }

      body.theme-sunrise-zugspitze {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_germany_zugspitze.jpg");
      }

      body.theme-sunrise-montblanc {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_france_montblanc.jpg");
      }

      body.theme-sunrise-mountteide {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_spain_mountteide.jpg");
      }

      body.theme-sunrise-seoraksan {
        background-image: url("/assets/backgrounds/countrysunrise/sunrise_southkorea_seoraksan.jpg");
      }

      body.theme-desert-lopnur {
        background-image: url("/assets/backgrounds/vastdesert/desert_china_lopnur.jpg");
      }

      body.theme-desert-dunes {
        background-image: linear-gradient(120deg, #d5a34f 0%, #f6e1b0 40%, #c78c3a 70%, #a66a2a 100%);
      }

      body.theme-tokyo-night {
        background-image: url("/assets/backgrounds/citynightview/city_japan_tokyo.jpg");
      }

      body.theme-shanghai-bund {
        background-image: url("/assets/backgrounds/citynightview/city_china_shanghai.jpg");
      }

      body.theme-taiwan-tech-island {
        background-image: url("/assets/backgrounds/tech_taiwan_blue_1.jpg");
      }

      body.theme-cross-sunrise {
        background-image: url("/assets/backgrounds/christian_cross_lightsunrise.jpg");
      }
.app-shell {
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        max-width: 520px;
        margin: 0 auto;
        padding: 110px 0 110px;
        gap: 6px;
        backdrop-filter: blur(var(--bg-blur-soft));
        position: relative;
        width: 100%;
        z-index: 1;
      }

      .top-bar {
        position: fixed;
        top: 0;
        left: 50%;
        transform: translateX(-50%);
        margin: 0 auto;
        z-index: 60;
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 12px 16px;
        min-height: 82jppx;
        width: calc(100% - 28px);
        max-width: 480px;
        border-radius: 18px;
        background: var(--header-bg-color);
        border: 1px solid rgba(255, 255, 255, 0.16);
        box-shadow: 0 12px 28px rgba(0, 0, 0, 0.28);
        color: #f5f4ff;
        backdrop-filter: blur(10px);
        overflow: visible;
      }

      .env-label-container {
        position: absolute;
        top: 8px;
        right: 10px;
      }

      .top-bar-actions {
        position: absolute;
        top: 80%;
        right: 10px;
        transform: translateY(-50%);
        display: flex;
        align-items: flex-end;
        justify-content: center;
        gap: 4px;
      }

      .top-home-button,
      .top-back-button {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        width: 36px;
        height: 36px;
        padding: 0;
        border-radius: 12px;
        border: 1px solid rgba(255, 255, 255, 0.28);
        background: var(--button-bg-color);
        color: #fdfcff;
        font-weight: 700;
        font-size: 0.8rem;
        cursor: pointer;
        box-shadow: 0 5px 12px rgba(0, 0, 0, 0.22);
        transition: transform 0.12s ease, background 0.12s ease, box-shadow 0.12s ease;
        align-self: flex-end;
      }

      .top-home-button:hover,
      .top-back-button:hover {
        transform: translateY(-1px);
        background: var(--button-bg-color);
        box-shadow: 0 8px 16px rgba(0, 0, 0, 0.28);
      }

      .top-home-button img,
      .top-back-button img {
        width: 98%;
        height: 98%;
        display: block;
      }

      .top-home-button:active,
      .top-back-button:active {
        transform: translateY(0);
        background: rgba(255, 255, 255, 0.15);
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
      }

      .sr-only {
        position: absolute;
        width: 1px;
        height: 1px;
        padding: 0;
        margin: -1px;
        overflow: hidden;
        clip: rect(0, 0, 0, 0);
        border: 0;
      }

      .app-title-group {
        display: flex;
        align-items: center;
        gap: 2px;
        margin-left: -14px;
        flex: 1;
        min-width: 0;
      }

      .app-logo-circle {
        width: 72px;
        height: 72px;
        border-radius: 22px;
        overflow: hidden;
        margin-left: -6px;
      }

      .app-logo-circle img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        display: block;
      }

      .app-text-main {
        font-family: var(--heading-font-family);
        flex: 1;
        min-width: 0;
        max-width: 84%;
        margin-left: -6px;
      }

      .app-title {
        font-size: 1rem;
        font-weight: 700;
        letter-spacing: 0.03em;
        color: var(--title-color);
        word-break: break-word;
        overflow-wrap: anywhere;
      }

      .app-subtitle {
        font-size: 0.72rem;
        color: var(--title-color);
        font-weight: 700;
        opacity: 0.85;
        word-break: break-word;
        overflow-wrap: anywhere;
      }

      .env-label {
        position: relative;
        top: -7px;
        font-size: 0.38rem;
        padding: 2px 6px;
        border-radius: 999px;
        background: rgba(255, 255, 255, 0.16);
        border: 1px solid rgba(255, 255, 255, 0.3);
        white-space: nowrap;
      }

      .screen-container {
        flex: 1;
        padding: 0 4px 16px;
        display: flex;
        flex-direction: column;
        gap: 8px;
      }

.screen {
        display: none;
        flex-direction: column;
        gap: 6px;
      }

      .screen.active {
        display: flex;
      }


      .hero-card {
        border-radius: 0;
        padding: 0;
        background: transparent;
        border: none;
        box-shadow: none;
        position: relative;
        overflow: visible;
        backdrop-filter: none;
      }

      .hero-main-title {
        font-family: var(--heading-font-family);
        font-size: 1rem;
        font-weight: 800;
        color: var(--title-color);
        margin: 0 0 0;
      }

.hero-lead {
  margin: 4px 0 6px;
  font-size: 0.95rem;
  line-height: 1.4;
  white-space: pre-line;
  color: var(--title-color);
  font-weight: 700;
}

      .hero-lead-icon {
        width: 40px;
        height: 40px;
        flex-shrink: 0;
        pointer-events: none;
        border: none;
        box-shadow: none;
        outline: none;
        background: transparent;
      }

      .hero-title-row {
        display: flex;
        align-items: center;
        gap: 4px;
        margin: 0 0 0;
        background: rgba(10, 12, 30, 0.0);
        border-radius: 12px;
        padding: 0px 0px;
        width: fit-content;
      }


.action-grid {
        display: flex;
        flex-direction: column;
        gap: 6px;
        margin-top: 0;
        align-items: flex-start;
      }

      .action-card {
        border-radius: 14px;
        padding: 10px 12px;
        background: var(--button-bg-color);
        border: 1px solid rgba(255, 255, 255, 0.2);
        box-shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
        display: flex;
        flex-direction: row;
        align-items: stretch;
        gap: 12px;
        min-height: 70px;
        cursor: pointer;
        transition: transform 0.12s ease, box-shadow 0.12s ease;
        backdrop-filter: blur(1.5px);
        justify-content: flex-start;
        width: 100%;
        max-width: 100%;
        min-width: 0;
      }

      .action-card:hover {
        transform: translateY(-2px);
        box-shadow: 0 10px 26px rgba(0, 0, 0, 0.2);
      }

      .action-card:active {
        transform: translateY(0);
        box-shadow: 0 8px 16px rgba(0, 0, 0, 0.22);
        background: rgba(255, 255, 255, 0.12);
      }

      .action-icon {
        font-size: 1.35rem;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        align-self: center;
      }

      .action-icon img {
        width: 38px;
        height: 38px;
        display: block;
      }


      .action-main {
        display: flex;
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        min-width: 90px;
        justify-content: center;
        flex: 1;
      }

      .action-text {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: 4px;
        flex: 1 1 auto;
        min-width: 0;
        justify-content: center;
      }

      .action-label {
        font-size: 0.9rem;
        font-weight: 700;
        color: var(--title-color);
        text-align: left;
        width: 100%;
        word-break: break-word;
        overflow-wrap: anywhere;
      }

      .action-desc {
        font-size: 0.9rem;
        font-weight: 400;
        color: var(--body-color);
        opacity: 0.9;
        text-align: left;
        flex: 1;
        line-height: 1.4;
        width: 100%;
        word-break: break-word;
        overflow-wrap: anywhere;
      }

      .helper-hint {
        margin-top: 2px;
        font-size: 0.86rem;
        padding: 0;
        border-radius: 0;
        background: transparent;
        border: none;
        color: #f9f8ff;
        backdrop-filter: none;
      }

      .section-card {
        border-radius: 18px;
        padding: 14px 14px 12px;
        background: var(--block-bg-color);
        border: 1px solid rgba(255, 255, 255, 0.15);
        box-shadow: 0 18px 30px rgba(0, 0, 0, 0.2);
        backdrop-filter: blur(2px);
        position: relative;
        overflow: visible;
      }

      .section-title {
        font-family: var(--heading-font-family);
        font-weight: 700;
        font-size: 0.98rem;
        color: var(--title-color);
        margin-bottom: 8px;
      }

      .section-title.with-icon {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        vertical-align: middle;
      }

      .section-title-icon {
        width: 30px;
        height: 30px;
        flex-shrink: 0;
        display: inline-block;
      }

      .teach-section .section-title {
        margin-bottom: 4px;
      }

      .teach-section .section-text {
        margin-top: 0;
        margin-bottom: 6px;
      }

      .section-text {
        font-size: 0.86rem;
        font-weight: 200;
        line-height: 1.5;
        margin-bottom: 6px;
      }

      .teach-list {
        list-style: none;
        margin: 0;
        padding: 0;
        display: flex;
        flex-direction: column;
        gap: 6px;
      }

      .teach-item {
        padding: 8px 10px;
        border-radius: 10px;
        background: var(--block-bg-color);
        border: 1px solid rgba(190, 185, 255, 0.4);
        font-size: 0.86rem;
        cursor: pointer;
        backdrop-filter: blur(1px);
        display: flex;
        align-items: center;
        gap: 10px;
      }

      .teach-item:hover {
        background: rgba(255, 255, 255, 0.08);
      }

      .teach-item:active {
        background: rgba(255, 255, 255, 0.14);
      }

      .teach-item.placeholder {
        cursor: default;
      }

      .teach-order {
        font-weight: 700;
        min-width: 18px;
        color: var(--title-color);
      }

      .teach-empty {
        opacity: 0.65;
      }

      .teach-tabs {
        display: flex;
        gap: 8px;
        margin: 6px 0 12px;
      }

      .teach-category-row {
        display: flex;
        align-items: center;
        gap: 8px;
        margin: 2px 0 6px;
        flex-wrap: nowrap;
        width: 100%;
      }

      .teach-category-row .section-title {
        display: inline-flex;
        align-items: center;
        margin: 0;
        padding: 0;
        white-space: nowrap;
      }

      .dropdown-inline {
        min-width: 160px;
        flex: 1 1 0;
        max-width: 100%;
        width: auto;
      }

      .teach-category-row .dropdown-inline {
        flex: 1 1 0;
        max-width: 100%;
      }

      .teach-topics-label {
        margin: 2px 0 4px;
        font-size: 0.98rem;
        font-weight: 700;
        color: var(--title-color);
        width: 100%;
        display: block;
      }

      @media (max-width: 640px) {
        .teach-category-row {
          flex-wrap: wrap;
          flex-direction: column;
          align-items: flex-start;
        }
        .dropdown-inline {
          width: 100%;
          min-width: 100%;
        }
        .teach-category-row .dropdown-inline {
          max-width: 100%;
        }
      }

      .teach-tab {
        flex: 1;
        padding: 10px 12px;
        border-radius: 12px;
        border: 1px solid rgba(255, 255, 255, 0.2);
        background: var(--button-bg-color);
        color: var(--title-color);
        font-weight: 700;
        font-size: 0.9rem;
        cursor: pointer;
        transition: all 0.12s ease;
      }

      .teach-tab.active {
        background: var(--button-bg-color);
        border: 4px solid rgba(255, 255, 255, 0.45);
        color: var(--title-color);
        box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.15);
      }

      .teach-tab-panel {
        display: none;
      }

      .teach-tab-panel.active {
        display: block;
      }

      .teach-panel-wrapper {
        position: relative;
        max-height: 340px;
        overflow: hidden;
        margin-top: 4px;
      }

      .teach-scroll {
        max-height: 340px;
        overflow-y: auto;
        padding-right: 4px;
      }

      .teach-category-status {
        font-size: 0.9rem;
        opacity: 0.7;
        color: var(--body-color);
      }

      .settings-sticky {
        position: sticky;
        top: 8px;
        z-index: 5;
      }

      .note-textarea {
        width: 100%;
        min-height: 110px;
        border-radius: 12px;
        border: 1px solid rgba(255, 255, 255, 0.4);
        padding: 8px 10px;
        font-size: 0.86rem;
        resize: vertical;
        box-sizing: border-box;
        background: var(--block-bg-color);
        color: #fefefe;
        backdrop-filter: blur(1px);
      }

      .primary-button {
        margin-top: 8px;
        border-radius: 999px;
        border: 1px solid rgba(255, 255, 255, 0.3);
        padding: 8px 14px;
        font-size: 0.86rem;
        font-weight: 600;
        background: var(--button-bg-color);
        color: #fff;
        cursor: pointer;
        display: inline-flex;
        align-items: center;
        gap: 6px;
        box-shadow: 0 6px 18px rgba(0, 0, 0, 0.25);
        backdrop-filter: blur(1px);
      }

      .primary-button:active {
        transform: translateY(1px);
        box-shadow: 0 3px 10px rgba(0, 0, 0, 0.35);
      }

      /* Settings page spacing tweaks */
      #screen-settings .section-card {
        margin-top: -8px;
        padding-top: 6px;
        padding-bottom: 8px;
      }

      #screen-settings .settings-sticky {
        margin-top: -12px;
      }

      #screen-settings .section-title {
        margin-bottom: 4px;
      }

      .bg-category-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
      }

      #bg-category-select {
        width: 100%;
      }

      .theme-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        width: 100%;
      }

      #bg-theme-select {
        width: 100%;
        max-width: 100%;
        flex: 1 1 100%;
      }

      .lang-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        width: 100%;
      }

      #lang-select,
      #content-lang-select {
        width: 100%;
        max-width: 100%;
        flex: 1 1 100%;
      }

      .text-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        width: 100%;
      }

      #font-size-select,
      #title-color-select,
      #body-color-select {
        width: 100%;
        max-width: 100%;
        flex: 1 1 100%;
      }

      .ui-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
        width: 100%;
      }

      #icon-style-select,
      #header-bg-select,
      #block-bg-select,
      #button-bg-select {
        width: 100%;
        max-width: 100%;
        flex: 1 1 100%;
      }

      .teach-split {
        align-items: flex-start;
      }

      .teach-split .action-icon {
        margin-top: 4px;
      }

      .teach-split .action-text {
        align-items: flex-start;
      }

      .note-list {
        list-style: none;
        margin: 0;
        padding: 0;
        display: flex;
        flex-direction: column;
        gap: 6px;
        max-height: 160px;
        overflow-y: auto;
      }

      .note-item {
        padding: 6px 8px;
        border-radius: 8px;
        background: var(--block-bg-color);
        border: 1px solid rgba(205, 205, 240, 0.4);
        font-size: 0.8rem;
        backdrop-filter: blur(1px);
      }

      .note-date {
        font-size: 0.72rem;
        opacity: 0.7;
        margin-bottom: 2px;
      }

      .qa-list {
        display: flex;
        flex-direction: column;
        gap: 10px;
      }

      .qa-card {
        border-radius: 12px;
        border: 1px solid rgba(150, 150, 210, 0.4);
        background: var(--block-bg-color);
        padding: 10px 12px;
        box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
        backdrop-filter: blur(1px);
      }

      .qa-question {
        display: flex;
        align-items: flex-start;
        font-weight: 700;
        color: var(--title-color);
        font-family: var(--heading-font-family);
        gap: 6px;
        margin-bottom: 6px;
      }

      .qa-icon {
        font-size: 1rem;
      }

      .qa-answer {
        margin: 0 0 6px;
        font-size: 0.86rem;
        line-height: 1.4;
      }

      .qa-steps {
        margin: 0;
        padding-left: 20px;
        font-size: 0.78rem;
        color: rgba(50, 50, 70, 0.9);
      }

      .qa-tags {
        margin: 8px 0 0;
        display: flex;
        flex-wrap: wrap;
        gap: 6px;
      }

      .qa-tag {
        font-size: 0.72rem;
        padding: 2px 8px;
        border-radius: 999px;
        background: rgba(107, 91, 255, 0.12);
        color: var(--accent);
      }

      .form-grid {
        display: flex;
        flex-direction: column;
        gap: 8px;
      }

      .form-row {
        display: flex;
        align-items: left;
        justify-content: flex-start;
        gap: 8px;
      }

      .form-row.color-row {
        flex-direction: column;
        align-items: flex-start;
      }

      .form-label {
        font-size: 0.84rem;
        color: var(--title-color);
        font-weight: 700;
      }

      .color-row .form-label {
        margin-bottom: 4px;
      }

      .body-color-row .color-picker {
        background: rgba(10, 12, 30, 0.15);
        border-radius: 14px;
        padding: 12px;
        border: 1px solid rgba(255, 255, 255, 0.2);
      }

      .form-select {
        flex: 0 0 52%;
        padding: 8px 10px;
        border-radius: 14px;
        border: 1px solid rgba(150, 150, 190, 0.65);
        font-size: 0.88rem;
        background: rgba(255, 255, 255, calc(var(--ui-opacity) * 0.4));
        color: #fefefe;
        backdrop-filter: blur(0.75px);
      }

      .form-select:focus {
        outline: none;
        box-shadow: 0 0 0 2px rgba(107, 91, 255, 0.4);
      }

      .color-picker {
        display: flex;
        flex-wrap: wrap;
        gap: 8px;
        width: 100%;
        background: rgba(10, 12, 30, 0.15);
        border-radius: 14px;
        padding: 10px;
        border: 1px solid rgba(255, 255, 255, 0.2);
        backdrop-filter: blur(1px);
      }

      .color-select {
        min-height: 46px;
      }

      .color-dropdown {
        position: relative;
        width: 100%;
        flex: 0 0 52%;
        max-width: 52%;
        z-index: 300;
      }

      .color-dropdown.full-width {
        flex: 1 1 100%;
        max-width: 100%;
      }

      .color-dropdown-trigger {
        width: 100%;
        border-radius: 14px;
        border: 1px solid rgba(150, 150, 190, 0.65);
        background: rgba(255, 255, 255, calc(var(--ui-opacity) * 0.4));
        color: var(--body-color);
        padding: 10px 12px;
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 10px;
        font-size: 0.9rem;
        cursor: pointer;
      }

      .color-dropdown-trigger:active {
        background: rgba(255, 255, 255, calc(var(--ui-opacity) * 0.55));
        box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.2);
      }

.color-dropdown-trigger .selected {
        display: inline-flex;
        align-items: center;
        gap: 10px;
        text-align: left;
        justify-content: flex-start;
        width: 100%;
      }

      .color-swatch-square {
        width: 18px;
        height: 18px;
        border-radius: 4px;
        border: 1px solid rgba(255, 255, 255, 0.4);
        flex-shrink: 0;
      }

      .color-dropdown-arrow {
        font-size: 0.8rem;
        opacity: 0.8;
        color: var(--body-color);
      }

      .color-dropdown-list {
        position: fixed;
        border-radius: 14px;
        border: 1px solid rgba(255, 255, 255, 0.2);
        /* 將透明度較設定值降低 40%，提高可讀性 */
        background: rgba(10, 12, 30, calc(0.76 + var(--ui-opacity) * 0.24));
        box-shadow: 0 12px 30px rgba(0, 0, 0, 0.35);
        max-height: min(270px, 70vh); /* 足以顯示 6 筆項目，同時避免超出視窗 */
        overflow-y: auto;
        z-index: 9999;
        display: none;
      }

      .color-dropdown-item {
        display: flex;
        align-items: center;
        gap: 10px;
        padding: 8px 12px;
        cursor: pointer;
        font-size: 0.94rem;
        color: var(--body-color);
      }

      .color-dropdown-item.disabled {
        opacity: 0.5;
        cursor: not-allowed;
        pointer-events: none;
      }

      .color-dropdown-item:hover {
        background: rgba(255, 255, 255, 0.08);
      }

      .color-dropdown-item.active {
        background: rgba(255, 255, 255, 0.12);
      }

      .slider-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
      }

      .slider-labels {
        width: 70%;
        margin: 0 auto;
        display: flex;
        justify-content: space-between;
        font-size: 0.8rem;
        opacity: 0.85;
      }

      .slider-track {
        width: 70%;
        margin: 0 auto;
        position: relative;
      }

      .slider-track input[type="range"] {
        width: 100%;
        accent-color: var(--accent);
      }

      .slider-value {
        position: absolute;
        top: -14px;
        left: 50%;
        transform: translateX(-50%);
        font-size: 0.78rem;
        color: #fefefe;
        opacity: 0.9;
      }

      .about-list {
        list-style: none;
        margin: 0;
        padding: 0;
        font-size: 0.84rem;
        display: flex;
        flex-direction: column;
        gap: 4px;
      }

      .about-key {
        opacity: 0.76;
        margin-right: 4px;
      }

      #floating-ai {
        position: fixed;
        right: 0px;
        bottom: 0px;
        display: none;
        width: 20vw;
        height: 20vw;
        min-width: 128px;
        min-height: 128px;
        max-width: 280px;
        max-height: 280px;
        z-index: 10000; /* 最高層，避免被浮層遮住 */
        pointer-events: none;
        opacity: calc(0.6 + var(--ui-opacity) * 0.4);
      }

      #floating-ai.show {
        display: block;
      }

      #floating-ai img {
        width: 100%;
        height: 100%;
        object-fit: contain;
        display: block;
      }

      /* 首次語言選擇浮層 */
      .lang-first-overlay {
        position: fixed;
        inset: 0;
        background: linear-gradient(140deg, rgba(8, 10, 24, 0.86), rgba(10, 12, 30, 0.78));
        backdrop-filter: blur(calc(var(--bg-blur, 3px) + 4px)) brightness(var(--bg-brightness, 1));
        --title-color: #E0F1FF; /* city night preset */
        --body-color: #F8F5EF;
        --header-bg-color: rgba(75, 63, 109, 0.2);
        --block-bg-color: rgba(75, 63, 109, 0.2);
        --button-bg-color: rgba(36, 58, 122, 0.2);
        --ui-opacity: 0.2;
        display: none;
        align-items: center;
        justify-content: center;
        padding: 18px;
        z-index: 6000;
      }

      .lang-first-overlay.show {
        display: flex;
      }

      .lang-bubble {
        position: relative;
        max-width: 640px;
        width: 100%;
        background: var(--block-bg-color, rgba(12, 14, 30, 0.9));
        border: 1px solid rgba(255, 255, 255, 0.28);
        border-radius: 18px;
        padding: 18px 18px 16px;
        box-shadow: 0 18px 36px rgba(0, 0, 0, 0.38);
        color: var(--title-color, #fdfcff);
        max-height: 82vh;
        overflow: hidden;
      }

      .lang-bubble::after {
        content: "";
        position: absolute;
        right: 32px;
        bottom: -18px;
        border-width: 18px 14px 0 14px;
        border-style: solid;
        border-color: var(--block-bg-color, rgba(12, 14, 30, 0.9)) transparent transparent transparent;
        filter: drop-shadow(0 6px 10px rgba(0, 0, 0, 0.3));
      }

      .lang-bubble h3 {
        margin: 0 0 4px;
        font-size: 1.12rem;
        letter-spacing: 0.01em;
      }

      .lang-bubble p {
        margin: 0 0 12px;
        font-size: 0.96rem;
        opacity: 0.92;
        line-height: 1.5;
      }

      .lang-option-grid {
        display: flex;
        flex-direction: column;
        gap: 10px;
        max-height: 56vh;
        overflow-y: auto;
        padding-right: 2px;
      }

      .lang-option-btn {
        width: 100%;
        padding: 10px 12px;
        border-radius: 12px;
        border: 1px solid rgba(255, 255, 255, 0.24);
        background: var(--button-bg-color, rgba(255, 255, 255, 0.12));
        color: #fefefe;
        font-weight: 700;
        font-size: 0.96rem;
        cursor: pointer;
        box-shadow: 0 10px 24px rgba(0, 0, 0, 0.28);
        transition: transform 0.12s ease, box-shadow 0.12s ease, border-color 0.12s ease;
        text-align: center;
      }

      .lang-option-btn:hover {
        transform: translateY(-1px);
        border-color: rgba(255, 255, 255, 0.36);
        box-shadow: 0 12px 28px rgba(0, 0, 0, 0.32);
      }

      .lang-option-btn:active {
        transform: translateY(0);
        box-shadow: 0 6px 14px rgba(0, 0, 0, 0.26);
      }

      .lang-note {
        margin-top: 10px;
        font-size: 0.82rem;
        opacity: 0.76;
        text-align: right;
      }

      @media (max-width: 360px) {
        .hero-card {
          padding: 14px 12px 12px;
        }

        .action-card {
          min-height: 72px;
        }
      }