CSS login form lamp animation | HTML, CSS & JavaScript

* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    }

body {
      background: #121212;
      display: flex;
      justify-content: center;
      align-items: center;
      min-height: 100vh;
      overflow: hidden;
      transition: background 0.5s ease;
    }

/* --- THE INVISIBLE SWITCH --- */
    #lamp-switch {
      display: none;
    }

/* --- LAMP FIXTURE --- */
    .lamp-wrapper {
      position: absolute;
      top: 0;
      left: 50%;
      transform: translateX(-50%);
      display: flex;
      flex-direction: column;
      align-items: center;
      z-index: 10;
    }

.wire {
      width: 4px;
      height: 80px;
      background: #2a2a2a;
    }

.fixture {
      width: 70px;
      height: 25px;
      background: #333;
      border-radius: 10px 10px 0 0;
      z-index: 2;
    }

.bulb {
      width: 45px;
      height: 45px;
      background: #222;
      border-radius: 50%;
      position: relative;
      top: -15px;
      z-index: 1;
      transition: all 0.4s ease;
    }

/* --- UPDATED PULL CORD (Larger Click Area) --- */
    .cord {
      position: absolute;
      top: 90px;
      right: 0px; 
      width: 40px; /* Much wider invisible hit-area for easy clicking */
      height: 70px;
      cursor: pointer;
      z-index: 20;
      transition: transform 0.15s ease-out;
    }

/* The visual string of the cord */
    .cord::before {
      content: '';
      position: absolute;
      top: 0;
      left: 18px; /* Centered in the 40px hit area */
      width: 3px;
      height: 100%;
      background: #444;
      transition: background 0.3s ease;
    }

/* The visual knob of the cord */
    .cord::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 14px; /* Centered in the 40px hit area */
      width: 11px;
      height: 11px;
      background: #666;
      border-radius: 50%;
      transition: background 0.3s ease;
    }

/* Pull animation when clicking anywhere in the 40px hit area */
    .cord:active {
      transform: translateY(15px);
    }

/* --- LIGHT BEAM --- */
    .light-beam {
      position: absolute;
      top: 110px;
      left: 50%;
      transform: translateX(-50%);
      width: 700px;
      height: 800px;
      clip-path: polygon(50% 0, 100% 100%, 0 100%);
      background: linear-gradient(to bottom, rgba(255, 235, 59, 0.4), transparent);
      opacity: 0;
      pointer-events: none; /* Let clicks pass through to the form */
      z-index: 1;
      transition: opacity 0.5s ease;
    }

/* --- LOGIN FORM --- */
    .form-container {
      position: relative;
      z-index: 2;
      background: rgba(20, 20, 20, 0.95);
      padding: 50px 40px;
      border-radius: 15px;
      width: 380px;
      margin-top: 120px;
      text-align: center;
      border: 1px solid #222;
      
      /* Dark/Disabled state by default */
      opacity: 0.2;
      pointer-events: none; 
      transition: all 0.5s ease;
    }

.form-container h2 {
      color: #444;
      margin-bottom: 40px;
      font-weight: 600;
      transition: color 0.5s ease;
      letter-spacing: 1px;
    }

.input-box {
      position: relative;
      margin-bottom: 35px;
      text-align: left;
    }

.input-box input {
      width: 100%;
      padding: 10px 0;
      font-size: 16px;
      color: #fff;
      background: transparent;
      border: none;
      border-bottom: 2px solid #444;
      outline: none;
      transition: border-color 0.5s ease;
    }

.input-box label {
      position: absolute;
      top: 10px;
      left: 0;
      font-size: 16px;
      color: #555;
      pointer-events: none;
      transition: all 0.3s ease;
    }

/* Floating label effect */
    .input-box input:focus ~ label,
    .input-box input:valid ~ label {
      top: -20px;
      font-size: 13px;
    }

button {
      width: 100%;
      background: #333;
      color: #666;
      border: none;
      padding: 15px;
      border-radius: 8px;
      font-size: 16px;
      font-weight: bold;
      cursor: pointer;
      transition: all 0.4s ease;
    }

/* =========================================
       STATES WHEN THE LAMP IS TURNED ON
       ========================================= */

/* 1. Light up the bulb */
    #lamp-switch:checked ~ .lamp-wrapper .bulb {
      background: #ffeb3b;
      box-shadow: 0 0 30px #ffeb3b, 0 0 80px #ffeb3b;
    }

/* 2. Fade in the light beam */
    #lamp-switch:checked ~ .light-beam {
      opacity: 1;
    }

/* 3. Wake up the form (enable clicks & typing) */
    #lamp-switch:checked ~ .form-container {
      opacity: 1;
      pointer-events: auto; 
      box-shadow: 0 15px 35px rgba(0,0,0,0.8), 0 0 40px rgba(255, 235, 59, 0.1);
      border-color: rgba(255, 235, 59, 0.3);
    }

/* 4. Brighten form text and inputs */
    #lamp-switch:checked ~ .form-container h2 {
      color: #ffeb3b;
    }

#lamp-switch:checked ~ .form-container .input-box input {
      border-bottom-color: #ddd;
    }

#lamp-switch:checked ~ .form-container .input-box label {
      color: #aaa;
    }

/* 5. Highlight active input fields in yellow */
    #lamp-switch:checked ~ .form-container .input-box input:focus ~ label,
    #lamp-switch:checked ~ .form-container .input-box input:valid ~ label {
      color: #ffeb3b;
    }

/* 6. Brighten and activate the login button */
    #lamp-switch:checked ~ .form-container button {
      background: #ffeb3b;
      color: #121212;
      box-shadow: 0 0 15px rgba(255, 235, 59, 0.4);
    }

#lamp-switch:checked ~ .form-container button:hover {
      background: #fff;
      box-shadow: 0 0 25px rgba(255, 255, 255, 0.8);
    }

- CSS login form lamp animation

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