.payment-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
      max-width: 820px;
      margin: 0 auto;
    }

    .form-group { margin-bottom: 1.2rem; }
    .form-label {
      display: block;
      font-family: var(--font-mono);
      font-size: 0.68rem;
      color: var(--text-dim);
      letter-spacing: 0.1em;
      text-transform: uppercase;
      margin-bottom: 0.45rem;
    }
    .form-input {
      width: 100%;
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 4px;
      color: var(--text);
      font-family: var(--font-mono);
      font-size: 0.9rem;
      padding: 0.7rem 1rem;
      outline: none;
      transition: border-color 0.2s, box-shadow 0.2s;
    }
    .form-input:focus { border-color: var(--cyan); box-shadow: 0 0 0 2px rgba(0,229,255,0.12); }
    .form-input.error { border-color: var(--red); }
    .form-input.valid { border-color: var(--green); }
    .form-error {
      font-family: var(--font-mono);
      font-size: 0.65rem;
      color: var(--red);
      margin-top: 0.35rem;
      display: none;
    }
    .form-error.show { display: block; }

    .amount-wrap { position: relative; }
    .amount-wrap .form-input { padding-right: 5rem; }
    .amount-max {
      position: absolute;
      right: 0.6rem; top: 50%;
      transform: translateY(-50%);
      font-family: var(--font-mono);
      font-size: 0.62rem;
      color: var(--cyan);
      background: rgba(0,229,255,0.08);
      border: 1px solid rgba(0,229,255,0.25);
      border-radius: 3px;
      padding: 0.2rem 0.5rem;
      cursor: pointer;
    }
    .amount-max:hover { background: rgba(0,229,255,0.18); }

    .balance-hint {
      display: flex;
      justify-content: space-between;
      font-family: var(--font-mono);
      font-size: 0.68rem;
      color: var(--text-dim);
      margin-top: 0.4rem;
    }
    .balance-hint .val { color: var(--green); }

    .addr-preview {
      font-family: var(--font-mono);
      font-size: 0.68rem;
      color: var(--text-dim);
      margin-top: 0.35rem;
      word-break: break-all;
    }

    /* Preset stand wallets */
    .preset-title {
      font-family: var(--font-mono);
      font-size: 0.65rem;
      color: var(--text-dim);
      letter-spacing: 0.1em;
      text-transform: uppercase;
      margin-bottom: 0.5rem;
    }
    .preset-list { display: flex; flex-direction: column; gap: 0.5rem; }
    .preset-item {
      display: flex;
      align-items: center;
      gap: 0.8rem;
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 4px;
      padding: 0.65rem 0.9rem;
      cursor: pointer;
      transition: border-color 0.15s;
    }
    .preset-item:hover { border-color: var(--cyan); }
    .preset-item.selected { border-color: var(--cyan); background: rgba(0,229,255,0.06); }
    .preset-icon { font-size: 1.2rem; flex-shrink: 0; }
    .preset-name { font-weight: 600; font-size: 0.85rem; }
    .preset-addr { font-family: var(--font-mono); font-size: 0.6rem; color: var(--text-dim); }

    /* Summary */
    .summary-row {
      display: flex;
      justify-content: space-between;
      padding: 0.55rem 0;
      border-bottom: 1px solid var(--border);
      font-size: 0.88rem;
    }
    .summary-row:last-of-type { border: none; }
    .summary-row .s-label { color: var(--text-dim); }
    .summary-row .s-addr { font-family: var(--font-mono); font-size: 0.7rem; color: var(--cyan); max-width: 160px; overflow: hidden; text-overflow: ellipsis; }
    .total-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0.8rem 0 0;
    }
    .total-row .t-label { font-family: var(--font-display); font-size: 0.72rem; letter-spacing: 0.1em; color: var(--text-dim); }
    .total-row .t-val { font-family: var(--font-display); font-size: 1.5rem; font-weight: 900; color: var(--cyan); text-shadow: var(--glow-cyan); }

    /* Success */
    #success-screen { display: none; text-align: center; padding: 1rem; }
    .success-icon { font-size: 3rem; margin-bottom: 0.6rem; animation: popIn 0.4s cubic-bezier(.36,1.4,.6,1); }
    .success-title { font-family: var(--font-display); font-size: 1.1rem; font-weight: 900; color: var(--green); text-shadow: var(--glow-green); letter-spacing: 0.1em; margin-bottom: 0.4rem; }
    .success-detail { font-family: var(--font-mono); font-size: 0.72rem; color: var(--text-dim); margin-bottom: 0.3rem; }
    .tx-hash-box { background: var(--bg-card); border: 1px solid var(--border); border-radius: 4px; padding: 0.6rem; font-family: var(--font-mono); font-size: 0.62rem; color: var(--cyan); word-break: break-all; margin: 0.8rem 0; }
    @keyframes popIn { from { transform: scale(0.5); opacity: 0; } to { transform: scale(1); opacity: 1; } }

    /* History */
    .history-list { display: flex; flex-direction: column; gap: 0.5rem; }
    .history-item { display: flex; align-items: center; gap: 0.8rem; background: var(--bg-card); border: 1px solid var(--border); border-radius: 4px; padding: 0.65rem 0.9rem; }
    .h-icon { width: 28px; height: 28px; border-radius: 50%; background: rgba(255,45,85,0.12); color: var(--red); display: flex; align-items: center; justify-content: center; font-size: 0.8rem; flex-shrink: 0; }
    .h-desc { font-size: 0.82rem; font-weight: 600; }
    .h-addr { font-family: var(--font-mono); font-size: 0.6rem; color: var(--text-dim); }
    .h-amount { font-family: var(--font-display); font-size: 0.9rem; color: var(--red); }
    .h-time { font-family: var(--font-mono); font-size: 0.6rem; color: var(--text-dim); text-align: right; }
    .empty-hint { font-family: var(--font-mono); font-size: 0.72rem; color: var(--text-dim); text-align: center; padding: 1.5rem; }

    @media (max-width: 650px) { .payment-layout { grid-template-columns: 1fr; } }