:root {
        --primary: #f37021;
        --secondary: #2e3192;
        --bg: #f8fafc;
        --card: #ffffff;
        --text: #1e293b;
        --muted: #64748b;
        --success: #10b981;
        --danger: #ef4444;
      }

      * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
        font-family: "Inter", sans-serif;
      }
      body {
        background: #e2e8f0;
        display: flex;
        justify-content: center;
        min-height: 100vh;
      }

      .app-shell {
        width: 100%;
        max-width: 420px;
        background: var(--bg);
        min-height: 100vh;
        position: relative;
        box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
        overflow-x: hidden;
      }

      /* --- LOGIN SCREEN --- */
      #login-screen {
        padding: 40px 25px;
        text-align: center;
        display: flex;
        flex-direction: column;
        align-items: center;
        height: 100vh;
        justify-content: center;
      }
      .login-logo {
        width: 180px;
        margin-bottom: 30px;
      }
      .login-card {
        background: white;
        padding: 30px 20px;
        border-radius: 20px;
        width: 100%;
        box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
      }
      .input-group {
        text-align: left;
        margin-bottom: 20px;
      }
      .input-group label {
        display: block;
        font-size: 0.8rem;
        font-weight: 600;
        margin-bottom: 8px;
        color: var(--secondary);
      }
      .input-group input {
        width: 100%;
        padding: 12px;
        border: 1px solid #cbd5e1;
        border-radius: 8px;
        outline: none;
      }
      .otp-row {
        display: flex;
        gap: 10px;
        align-items: center;
      }
      .btn-send {
        background: none;
        border: none;
        color: var(--primary);
        font-weight: bold;
        cursor: pointer;
        font-size: 0.8rem;
      }

      /* Buttons */
      .btn-primary {
        background: var(--success);
        color: white;
        border: none;
        width: 100%;
        padding: 14px;
        border-radius: 10px;
        font-weight: 700;
        cursor: pointer;
        margin-top: 10px;
      }