/* ========== CSS Variables (theme-driven) ========== */
    :root {
      --bg: #0a0a0f;
      --fg: #f0f0f5;
      --fg-muted: rgba(240, 240, 245, 0.55);
      --control-bg: rgba(255, 255, 255, 0.06);
      --control-border: rgba(255, 255, 255, 0.12);
      --control-hover: rgba(255, 255, 255, 0.12);
      --accent: #7c9cff;
      --donate: #ffc43a;
      --donate-fg: #1a1a1a;
      --panel-bg: rgba(12, 12, 18, 0.96);
      --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
      --radius: 10px;
      --transition: 0.2s ease;
    }

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

    html, body {
      height: 100%;
    }

    body {
      font-family: system-ui, -apple-system, "Segoe UI", "Noto Sans TC", "Noto Sans SC",
        "Hiragino Sans", "Yu Gothic", sans-serif;
      background: var(--bg);
      color: var(--fg);
      overflow: hidden;
      transition: background var(--transition), color var(--transition);
      -webkit-font-smoothing: antialiased;
    }

    /* ========== Layout ========== */
    .app {
      display: flex;
      flex-direction: column;
      height: 100%;
      min-height: 100dvh;
      position: relative;
      /* space for fixed bottom bar */
      padding-bottom: 4.25rem;
      box-sizing: border-box;
    }

    /* ========== Control Bar ========== */
    .controls {
      display: flex;
      align-items: center;
      gap: 0.6rem;
      padding: 0.75rem 1rem;
      flex-wrap: wrap;
      z-index: 100;
      position: relative;
    }

    .brand {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      text-decoration: none;
      color: var(--fg);
      flex-shrink: 0;
      margin-right: 0.25rem;
      border-radius: var(--radius);
      outline: none;
      transition: opacity var(--transition);
    }

    .brand:hover {
      opacity: 0.88;
    }

    .brand:focus-visible {
      box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 50%, transparent);
    }

    .brand-logo {
      width: 2rem;
      height: 2rem;
      object-fit: contain;
      border-radius: 6px;
      display: block;
      background: #fff;
    }

    .brand-text {
      font-size: 0.95rem;
      font-weight: 650;
      letter-spacing: 0.02em;
      white-space: nowrap;
    }

    .controls select,
    .donate-btn,
    .fs-btn {
      appearance: none;
      -webkit-appearance: none;
      font: inherit;
      font-size: 0.85rem;
      border-radius: var(--radius);
      border: 1px solid var(--control-border);
      background: var(--control-bg);
      color: var(--fg);
      padding: 0.45rem 0.85rem;
      cursor: pointer;
      transition: background var(--transition), border-color var(--transition);
      outline: none;
    }

    .fs-btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.4rem;
      white-space: nowrap;
      font-weight: 600;
    }

    .fs-btn:hover,
    .fs-btn:focus-visible {
      background-color: var(--control-hover);
      border-color: var(--accent);
    }

    .fs-btn:focus-visible {
      box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 40%, transparent);
    }

    .fs-btn .fs-icon {
      width: 1.1rem;
      height: 1.1rem;
      flex-shrink: 0;
      display: block;
    }

    /* Enter / exit icons: show exactly one, driven by aria-pressed (and [hidden] fallback) */
    .fs-btn #fsIconEnter {
      display: block;
    }

    .fs-btn #fsIconExit,
    .fs-btn .fs-icon[hidden] {
      display: none !important;
    }

    .fs-btn[aria-pressed="true"] #fsIconEnter {
      display: none !important;
    }

    .fs-btn[aria-pressed="true"] #fsIconExit {
      display: block !important;
    }

    .fs-btn[hidden] {
      display: none !important;
    }

    /* Bottom bar: donate | date+weekday+tz (nowrap) | fullscreen */
    .bottom-bar {
      position: fixed;
      left: 0;
      right: 0;
      bottom: 0;
      z-index: 300;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 0.75rem;
      padding: 0.75rem 1rem;
      padding-bottom: max(0.75rem, env(safe-area-inset-bottom, 0px));
      padding-left: max(1rem, env(safe-area-inset-left, 0px));
      padding-right: max(1rem, env(safe-area-inset-right, 0px));
      pointer-events: none;
      box-sizing: border-box;
    }

    .bottom-bar .donate-btn,
    .bottom-bar .fs-btn {
      pointer-events: auto;
      flex-shrink: 0;
      box-shadow: var(--shadow);
    }

    .bottom-bar .date-meta {
      flex: 1 1 auto;
      min-width: 0;
      text-align: center;
      color: var(--fg-muted);
      font-size: clamp(0.8rem, 2vw, 1.05rem);
      letter-spacing: 0.03em;
      font-weight: 400;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
      transition: color var(--transition);
      pointer-events: none;
    }

    .bottom-bar .date-meta .meta-sep {
      margin: 0 0.4em;
      opacity: 0.55;
    }

    .controls select {
      padding-right: 1.8rem;
      background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%23aaa' d='M1 1l5 5 5-5'/%3E%3C/svg%3E");
      background-repeat: no-repeat;
      background-position: right 0.65rem center;
      max-width: 16rem;
    }

    .controls select:hover,
    .controls select:focus-visible {
      background-color: var(--control-hover);
      border-color: var(--accent);
    }

    .controls select:focus-visible {
      box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 40%, transparent);
    }

    .donate-btn {
      text-decoration: none;
      font-weight: 600;
      background: var(--donate) !important;
      color: var(--donate-fg) !important;
      border-color: transparent !important;
      white-space: nowrap;
    }

    .donate-btn:hover,
    .donate-btn:focus-visible {
      filter: brightness(1.08);
      box-shadow: 0 0 0 2px color-mix(in srgb, var(--donate) 50%, transparent);
    }

    .control-group {
      display: flex;
      align-items: center;
      gap: 0.4rem;
    }

    .control-label {
      font-size: 0.7rem;
      text-transform: uppercase;
      letter-spacing: 0.06em;
      color: var(--fg-muted);
      white-space: nowrap;
    }

    /* Hamburger — hidden on desktop/tablet */
    .menu-toggle {
      display: none;
      width: 2.5rem;
      height: 2.5rem;
      border: 1px solid var(--control-border);
      border-radius: var(--radius);
      background: var(--control-bg);
      color: var(--fg);
      cursor: pointer;
      align-items: center;
      justify-content: center;
      flex-direction: column;
      gap: 5px;
      padding: 0;
      z-index: 120;
      transition: background var(--transition);
    }

    .menu-toggle:hover,
    .menu-toggle:focus-visible {
      background: var(--control-hover);
    }

    .menu-toggle:focus-visible {
      outline: 2px solid var(--accent);
      outline-offset: 2px;
    }

    .menu-toggle span {
      display: block;
      width: 1.1rem;
      height: 2px;
      background: var(--fg);
      border-radius: 1px;
      transition: transform 0.25s ease, opacity 0.2s ease;
    }

    .menu-toggle[aria-expanded="true"] span:nth-child(1) {
      transform: translateY(7px) rotate(45deg);
    }

    .menu-toggle[aria-expanded="true"] span:nth-child(2) {
      opacity: 0;
    }

    .menu-toggle[aria-expanded="true"] span:nth-child(3) {
      transform: translateY(-7px) rotate(-45deg);
    }

    .controls-inner {
      display: flex;
      align-items: center;
      gap: 0.6rem;
      flex-wrap: wrap;
      flex: 1;
    }

    /* ========== Digital clock font (DSEG7) ========== */
    @font-face {
      font-family: "DSEG7 Classic";
      src: url("/fonts/DSEG7Classic-Bold.woff2") format("woff2");
      font-weight: 700;
      font-style: normal;
      font-display: swap;
    }

    /* ========== Main Clock ========== */
    .clock-area {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 0.05rem 0.15rem;
      min-height: 0;
      width: 100%;
      overflow: hidden;
    }

    .time {
      font-family: "DSEG7 Classic", ui-monospace, monospace;
      /* Fallback only — JS fitTimeDisplay() sets exact px to fill .clock-area */
      font-size: 18vmin;
      font-weight: 700;
      letter-spacing: 0;
      line-height: 0.95;
      font-variant-numeric: tabular-nums;
      font-feature-settings: "tnum";
      direction: ltr;
      text-align: left;
      white-space: nowrap;
      width: max-content;
      max-width: none;
      box-sizing: border-box;
      user-select: none;
      color: var(--fg);
      text-shadow: 0 0 60px color-mix(in srgb, var(--fg) 12%, transparent);
      transition: color var(--transition);
      /* Portrait default: hour above, minutes+seconds below */
      display: flex;
      flex-direction: column;
      align-items: flex-start;
      gap: 0.22em;
    }

    .time .sep {
      display: none;
      opacity: 0.5;
      margin: 0;
      font-weight: 700;
    }

    .time .time-minsec {
      display: flex;
      align-items: flex-end;
      gap: 0.2em;
    }

    .time .time-seconds {
      font-size: 0.333em;
      line-height: 1;
      padding-bottom: 0.12em;
    }

    @media (orientation: landscape) {
      .time {
        flex-direction: row;
        align-items: flex-end;
        gap: 0;
      }

      .time .sep {
        display: inline;
      }

      .time .time-minsec {
        margin-left: 0;
      }
    }

    /* ========== Mobile ≤640px ========== */
    @media (max-width: 640px) {
      body {
        overflow: auto;
      }

      .menu-toggle {
        display: flex;
        margin-left: auto;
      }

      .controls {
        justify-content: flex-start;
        flex-wrap: nowrap;
        padding: 0.65rem 0.75rem;
      }

      .brand-logo {
        width: 1.85rem;
        height: 1.85rem;
      }

      .controls-inner {
        display: none;
        position: absolute;
        top: calc(100% + 0.25rem);
        right: 0.75rem;
        left: 0.75rem;
        flex-direction: column;
        align-items: stretch;
        gap: 0.65rem;
        padding: 1rem;
        background: var(--panel-bg);
        border: 1px solid var(--control-border);
        border-radius: calc(var(--radius) + 2px);
        box-shadow: var(--shadow);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
      }

      .controls-inner.is-open {
        display: flex;
      }

      .control-group {
        flex-direction: column;
        align-items: stretch;
        gap: 0.3rem;
      }

      .controls select {
        width: 100%;
        max-width: none;
        text-align: center;
        padding: 0.7rem 0.85rem;
      }

      .controls select {
        max-width: none;
      }
    }

    /* Phone / tablet landscape: shrink chrome so the clock area is larger */
    @media (max-height: 500px) and (orientation: landscape) {
      .app {
        padding-bottom: 2.75rem;
      }

      .controls {
        padding: 0.3rem 0.55rem;
      }

      .brand-logo {
        width: 1.5rem;
        height: 1.5rem;
      }

      .brand-text {
        font-size: 0.85rem;
      }

      .bottom-bar {
        gap: 0.5rem;
        padding: 0.35rem 0.55rem;
        padding-bottom: max(0.35rem, env(safe-area-inset-bottom, 0px));
        padding-left: max(0.55rem, env(safe-area-inset-left, 0px));
        padding-right: max(0.55rem, env(safe-area-inset-right, 0px));
      }

      .bottom-bar .donate-btn,
      .bottom-bar .fs-btn {
        font-size: 0.78rem;
        padding: 0.32rem 0.65rem;
      }

      .bottom-bar .date-meta {
        font-size: clamp(0.7rem, 2.2vh, 0.9rem);
      }

      .clock-area {
        padding: 0;
      }
    }

    /* Reduced motion */
    @media (prefers-reduced-motion: reduce) {
      *, *::before, *::after {
        transition-duration: 0.01ms !important;
      }
    }

    /* Visually hidden utility for a11y */
    .sr-only {
      position: absolute;
      width: 1px;
      height: 1px;
      padding: 0;
      margin: -1px;
      overflow: hidden;
      clip: rect(0, 0, 0, 0);
      white-space: nowrap;
      border: 0;
    }