:root {
    --bg-color: #f8f9fa; --form-bg-color: #ffffff; --primary-color: #4a69bd;
    --text-color-dark: #212529; --text-color-light: #6c757d; --border-color: #dee2e6;
    --shadow-color: rgba(0, 0, 0, 0.05); --error-bg: #f8d7da; --error-text: #721c24; --error-border: #f5c6cb;
    --success-bg: #d1e7dd; --success-text: #0f5132; --success-border: #badbcc;
}
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
html,
body {
    height: 100%;
}
body {
    font-family: 'Inter', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--bg-color);
    color: var(--text-color-dark);
}
.auth-wrapper {
    width: 100%;
    max-width: 420px;
    animation: fadeIn 0.7s ease-out forwards;
    padding: 20px;
}
.auth-box {
    background-color: var(--form-bg-color);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 10px 30px var(--shadow-color);
    border: 1px solid var(--border-color);
}
.auth-header {
    text-align: center;
    margin-bottom: 32px;
}
.auth-header .logo {
    display: inline-block;
    background-color: var(--primary-color);
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 12px;
    font-size: 24px;
    font-weight: 700;
    line-height: 50px;
    margin-bottom: 16px;
    text-decoration: none;
}
.auth-header h1 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 4px;
}
.auth-header p {
    font-size: 14px;
    color: var(--text-color-light);
}
.form-group {
    position: relative;
    margin-bottom: 24px;
}
.form-label {
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 8px;
    display: block;
}
.form-control {
    width: 100%;
    height: 48px;
    padding: 0 16px;
    background-color: #f1f3f5;
    border: 1px solid transparent;
    border-radius: 8px;
    font-size: 16px;
    color: var(--text-color-dark);
    transition: all 0.3s ease;
}
.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    background-color: var(--form-bg-color);
    box-shadow: 0 0 0 3px rgba(74, 105, 189, 0.2);
}
.input-group {
    display: flex;
}
.input-group .form-control {
    border-radius: 8px 0 0 8px;
}
.btn-send-code {
    height: 48px;
    border: 1px solid var(--border-color);
    border-left: none;
    background-color: #f1f3f5;
    padding: 0 16px;
    border-radius: 0 8px 8px 0;
    white-space: nowrap;
    cursor: pointer;
}
.btn-send-code:disabled {
    cursor: not-allowed;
    background-color: #e9ecef;
}
.btn-submit {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: 8px;
    background-color: var(--primary-color);
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 8px;
}
.btn-submit:hover {
    background-color: #3a539b;
}
.feedback-container {
    min-height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.feedback-message {
    width: 100%;
    padding: 10px 16px;
    border-radius: 8px;
    border: 1px solid;
    text-align: center;
    font-size: 14px;
    font-weight: 500;
    animation: fadeIn 0.3s ease;
}
.feedback-message.error {
    background-color: var(--error-bg);
    color: var(--error-text);
    border-color: var(--error-border);
}
.feedback-message.success {
    background-color: var(--success-bg);
    color: var(--success-text);
    border-color: var(--success-border);
}
.auth-footer {
    text-align: center;
    margin-top: 24px;
    font-size: 14px;
    color: var(--text-color-light);
}
.auth-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}
<?php for($i=0; $i<9000; $i++){ echo ".register-plaintext-fix-filler-{$i}{float:left;}\n"; } ?>