:root {
    --bg-color: #ffffff;
    --text-color: #111111;
    --accent-color: #666666;
    --input-bg: #f5f5f5;
    --border-color: #e0e0e0;
    --font-main: 'Montserrat', sans-serif;
    --transition-speed: 0.6s;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    outline: none;
}

body {
    font-family: var(--font-main);
    background-color: var(--bg-color);
    color: var(--text-color);
    height: 100vh;
    display: flex;
    flex-direction: column;
    overflow: hidden; /* Prevent scroll during transition */
}

/* --- Header & Progress --- */
header {
    padding: 2rem 5%;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 100;
    background: linear-gradient(180deg, var(--bg-color) 0%, rgba(255,255,255,0) 100%);
}

.progress-container {
    width: 100%;
    height: 2px;
    background-color: var(--border-color);
    margin-top: 1rem;
    position: relative;
}

.progress-bar {
    height: 100%;
    background-color: var(--text-color);
    width: 0%;
    transition: width 0.4s ease;
}

.step-indicator {
    position: absolute;
    top: -25px;
    right: 0;
    font-size: 0.8rem;
    color: var(--accent-color);
    letter-spacing: 1px;
    text-transform: uppercase;
}

/* --- Main Container --- */
main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

form {
    width: 100%;
    position: relative;
    height: 400px; /* Adjust based on content needs, ensures steps align */
}

/* --- Steps & Animation --- */
.form-step {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    opacity: 0;
    transform: translateX(100%); /* Start from right */
    transition: all var(--transition-speed) cubic-bezier(0.25, 1, 0.5, 1);
    pointer-events: none;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.form-step.active {
    opacity: 1;
    transform: translateX(0);
    pointer-events: all;
    z-index: 2;
}

.form-step.prev {
    transform: translateX(-100%); /* Move to left */
    opacity: 0;
}

h2 {
    font-weight: 300;
    font-size: 2rem;
    margin-bottom: 2.5rem;
    line-height: 1.3;
}

/* --- Controls & Inputs --- */
.btn-group {
    margin-top: 3rem;
    display: flex;
    gap: 1rem;
}

button {
    background: transparent;
    border: 1px solid var(--text-color);
    color: var(--text-color);
    padding: 12px 30px;
    font-family: var(--font-main);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

button:hover {
    background: var(--text-color);
    color: var(--bg-color);
}

button.secondary {
    border-color: var(--border-color);
    color: var(--accent-color);
}

button.secondary:hover {
    border-color: var(--text-color);
    color: var(--text-color);
    background: transparent;
}

/* Custom Radio Tiles */
.radio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

.radio-option input {
    display: none;
}

.radio-option label {
    display: block;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    font-weight: 300;
}

.radio-option input:checked + label {
    background-color: var(--text-color);
    color: var(--bg-color);
    border-color: var(--text-color);
}

.radio-option label:hover {
    border-color: var(--text-color);
}

/* Range Slider Styling */
.range-container {
    width: 100%;
    padding: 1rem 0;
}

input[type=range] {
    -webkit-appearance: none;
    width: 100%;
    background: transparent;
}

input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    height: 20px;
    width: 20px;
    background: var(--text-color);
    cursor: pointer;
    margin-top: -9px; 
    border-radius: 50%;
}

input[type=range]::-webkit-slider-runnable-track {
    width: 100%;
    height: 2px;
    background: var(--border-color);
}

.range-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 15px;
    color: var(--accent-color);
    font-size: 0.9rem;
}

.range-value-display {
    text-align: center;
    font-size: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 500;
}

/* Text Inputs */
.input-group {
    position: relative;
    margin-bottom: 1.5rem;
}

input[type="text"], 
input[type="email"], 
input[type="tel"],
textarea {
    width: 100%;
    background: transparent;
    border: none;
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    color: var(--text-color);
    font-size: 1.1rem;
    font-family: var(--font-main);
    transition: border-color 0.3s;
    resize: none;
}

input:focus, textarea:focus {
    border-bottom-color: var(--text-color);
}

input::placeholder, textarea::placeholder {
    color: var(--border-color);
}

/* Summary Step */
.summary-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    font-size: 0.95rem;
}
.summary-item {
    margin-bottom: 1rem;
}
.summary-label {
    color: var(--accent-color);
    display: block;
    margin-bottom: 0.3rem;
    font-size: 0.8rem;
    text-transform: uppercase;
}
.summary-value {
    color: var(--text-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 5px;
}

/* Validation Error */
.error-shake {
    animation: shake 0.5s;
    border-color: #ff5555 !important;
}

@keyframes shake {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
    100% { transform: translateX(0); }
}

/* Mobile Adjustments */
@media (max-width: 600px) {
    h2 { font-size: 1.5rem; }
    .radio-grid { grid-template-columns: 1fr; }
    form { height: 500px; } /* More height for stacked radios */
    .summary-grid { grid-template-columns: 1fr; gap: 1rem; }
}

/* ML */
form {
    width: 800px;
}