:root {
    /* Colors - Light Mode */
    --primary-main: hsl(210, 98%, 48%);
    --primary-light: hsl(210, 100%, 80%);
    --primary-dark: hsl(210, 100%, 35%);

    /* Background */
    --bg-default: hsl(0, 0%, 99%);
    --bg-paper: hsl(220, 35%, 97%);
    --bg-gradient: radial-gradient(ellipse at 50% 50%, hsl(210, 100%, 97%), hsl(0, 0%, 100%));

    /* Text */
    --text-primary: hsl(220, 30%, 6%);
    --text-secondary: hsl(220, 20%, 35%);
    --divider: hsla(220, 20%, 80%, 0.4);

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --border-radius: 8px;

    /* Shadows */
    --shadow-card: hsla(220, 30%, 5%, 0.07) 0px 4px 16px 0px, hsla(220, 25%, 10%, 0.07) 0px 8px 16px -5px;
    --shadow-input: 0 0 0 0px rgba(25, 118, 210, 0);
    --shadow-input-focus: 0 0 0 3px rgba(25, 118, 210, 0.15);

    /* Alert Colors */
    --error-bg: #fdeded;
    --error-border: #f5c6cb;
    --error-text: #721c24;
}

[data-theme="dark"] {
    /* Dark Mode Colors */
    --bg-default: hsl(220, 35%, 3%);
    --bg-paper: hsl(220, 30%, 7%);
    --bg-gradient: radial-gradient(at 50% 50%, hsla(210, 100%, 16%, 0.5), hsl(220, 30%, 5%));

    --text-primary: hsl(0, 0%, 100%);
    --text-secondary: hsl(220, 20%, 65%);
    --divider: hsla(220, 20%, 25%, 0.6);

    --shadow-card: hsla(220, 30%, 5%, 0.7) 0px 4px 16px 0px, hsla(220, 25%, 10%, 0.8) 0px 8px 16px -5px;

    --error-bg: rgba(211, 47, 47, 0.1);
    --error-border: rgba(211, 47, 47, 0.3);
    --error-text: #f48fb1;
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-default);
    background-image: var(--bg-gradient);
    background-repeat: no-repeat;
    background-attachment: fixed;
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Theme Toggle */
.theme-toggle-fixed {
    position: fixed;
    top: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    border: none;
    background: transparent;
    color: var(--text-primary);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.3s ease;
    z-index: 1000;
}

.theme-toggle-fixed:hover {
    background-color: rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] .theme-toggle-fixed:hover {
    background-color: rgba(255, 255, 255, 0.08);
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="dark"] .sun-icon {
    display: block;
}

[data-theme="dark"] .moon-icon {
    display: none;
}

/* Main Container */
.auth-main-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: var(--spacing-md);
}

/* Split Layout for Sign In */
.auth-split-container {
    display: flex;
    flex-direction: column-reverse;
    align-items: center;
    justify-content: center;
    gap: 48px;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md);
}

@media (min-width: 900px) {
    .auth-split-container {
        flex-direction: row;
        gap: 96px;
        padding: var(--spacing-xl);
    }
}

/* Left Content Panel */
.auth-content-panel {
    display: none;
    flex-direction: column;
    gap: 32px;
    max-width: 450px;
    align-self: center;
}

@media (min-width: 900px) {
    .auth-content-panel {
        display: flex;
    }
}

.content-features {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.feature-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

.feature-icon {
    color: var(--text-secondary);
    flex-shrink: 0;
    margin-top: 4px;
}

.feature-text h3 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 4px;
    color: var(--text-primary);
}

.feature-text p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Centered Layout for Sign Up */
.auth-centered-container {
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 450px;
    margin: 0 auto;
    width: 100%;
}

/* Auth Card Container */
.auth-card-container {
    width: 100%;
    max-width: 450px;
}

/* Auth Card */
.auth-card {
    background: var(--bg-paper);
    border: 1px solid var(--divider);
    border-radius: calc(var(--border-radius) + 4px);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-card);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    width: 100%;
}

@media (min-width: 640px) {
    .auth-card {
        padding: 48px;
    }
}

/* Logo */
.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.mobile-only {
    display: flex;
}

@media (min-width: 900px) {
    .mobile-only {
        display: none;
    }
}

.logo-icon {
    color: var(--primary-main);
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Title */
.auth-title {
    font-size: clamp(2rem, 10vw, 2.15rem);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

/* Alert */
.alert {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    line-height: 1.5;
}

.alert-error {
    background-color: var(--error-bg);
    border: 1px solid var(--error-border);
    color: var(--error-text);
}

.alert svg {
    flex-shrink: 0;
}

/* Form */
.auth-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-label-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 6px;
}

.forgot-link {
    font-size: 0.875rem;
    color: var(--primary-main);
    text-decoration: none;
    transition: color 0.3s ease;
}

.forgot-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

.form-input {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--divider);
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-family: var(--font-family);
    background-color: var(--bg-paper);
    color: var(--text-primary);
    transition: all 0.3s ease;
    box-shadow: var(--shadow-input);
}

.form-input:hover {
    border-color: var(--text-primary);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-main);
    box-shadow: var(--shadow-input-focus);
}

.form-input:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.form-input.error {
    border-color: #d32f2f;
}

.form-error {
    font-size: 0.75rem;
    color: #d32f2f;
    min-height: 18px;
    display: block;
}

/* Checkbox */
.form-checkbox {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.form-checkbox input[type="checkbox"] {
    width: 18px;
    height: 18px;
    border: 2px solid var(--divider);
    border-radius: 4px;
    cursor: pointer;
    accent-color: var(--primary-main);
}

.form-checkbox label {
    font-size: 0.875rem;
    color: var(--text-primary);
    cursor: pointer;
    user-select: none;
}

.form-checkbox input[type="checkbox"]:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.form-checkbox input[type="checkbox"]:disabled+label {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Button */
.btn {
    padding: 10px 16px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-family: var(--font-family);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-primary {
    background-color: var(--primary-main);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(25, 118, 210, 0.4);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-full {
    width: 100%;
}

.btn-loader {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

/* Divider */
.divider {
    display: flex;
    align-items: center;
    text-align: center;
    margin: var(--spacing-md) 0;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    border-bottom: 1px solid var(--divider);
}

.divider span {
    padding: 0 var(--spacing-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Footer Text */
.auth-footer-text {
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.auth-link {
    color: var(--primary-main);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.auth-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* Test Credentials */
.test-credentials {
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: -8px;
}

/* Loading State */
.loading .btn-text {
    display: none;
}

.loading .btn-loader {
    display: block;
}

/* Google Button */
.btn-google {
    background-color: #ffffff;
    color: #3c4043;
    border: 1px solid #dadce0;
    text-decoration: none;
    font-weight: 500;
}

.btn-google:hover {
    background-color: #f8f9fa;
    border-color: #d2d4d7;
    box-shadow: 0 1px 3px rgba(60, 64, 67, 0.15);
}

.btn-google svg {
    flex-shrink: 0;
}

[data-theme="dark"] .btn-google {
    background-color: #303134;
    color: #e8eaed;
    border-color: #5f6368;
}

[data-theme="dark"] .btn-google:hover {
    background-color: #3c4043;
    border-color: #8ab4f8;
}