/* ===================================
   CSS Variables & Root Styles
   =================================== */
   :root {
    /* Colors - Dark Theme */
    --bg-primary: #0a0e1a;
    --bg-secondary: #1a1f2e;
    --bg-tertiary: #252b3d;
    --bg-accent: #2d3548;
    
    --text-primary: #ffffff;
    --text-secondary: #cbd5e1;
    --text-tertiary: #8892a0;
    
    --accent-primary: #00d4ff;
    --accent-secondary: #0099cc;
    --accent-success: #00ff88;
    --accent-error: #ff4757;
    --accent-warning: #ffaa00;
    
    --border-primary: #334155;
    --border-secondary: #475569;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 2rem;
    
    /* Typography */
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    
    /* Transitions */
    --transition-base: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Shadows */
    --shadow-primary: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-secondary: 0 2px 10px rgba(0, 0, 0, 0.2);
    --shadow-large: 0 25px 50px rgba(0, 0, 0, 0.5);
}

/* Light Theme Variables */
body.light-theme {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-accent: #e2e8f0;
    
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-tertiary: #64748b;
    
    --border-primary: #e2e8f0;
    --border-secondary: #cbd5e1;
}

/* ===================================
   Base Styles
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    transition: var(--transition-base);
}

/* ===================================
   Header Styles
   =================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 14, 26, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-primary);
    z-index: 1000;
    height: 80px;
}

.navbar {
    height: 100%;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: var(--transition-base);
    z-index: 1002;
}

.nav-brand i {
    color: var(--accent-primary);
    font-size: var(--font-size-2xl);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.nav-brand:hover {
    transform: translateY(-2px);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav-link {
    position: relative;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-base);
    padding: var(--spacing-sm) 0;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-primary);
    transition: var(--transition-base);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border: none;
    background: var(--bg-accent);
    color: var(--text-secondary);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-base);
}

.theme-toggle:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition-base);
    font-family: inherit;
}

.btn-primary {
    background: var(--accent-primary);
    color: var(--bg-primary);
}

.btn-primary:hover {
    background: var(--accent-secondary);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-primary);
}

.btn-secondary:hover {
    background: var(--bg-accent);
}

/* Mobile menu toggle */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 24px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1002;
}

.mobile-menu-toggle span {
    display: block;
    width: 100%;
    height: 3px;
    background: var(--text-primary);
    border-radius: 3px;
    transition: var(--transition-base);
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: translateY(10.5px) rotate(45deg);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: translateY(-10.5px) rotate(-45deg);
}

/* Mobile-only actions - hide by default */
.mobile-only-actions {
    display: none;
}

/* ===================================
   Signup Container & Background
   =================================== */
.signup-wrapper {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl);
    padding-top: calc(80px + var(--spacing-2xl));
    padding-bottom: var(--spacing-2xl);
}

.signup-background {
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(0, 255, 136, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(255, 170, 0, 0.03) 0%, transparent 50%);
    background-size: 100% 100%;
    animation: backgroundFloat 20s ease-in-out infinite;
    z-index: -2;
}

.signup-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: gridMove 30s linear infinite;
}

@keyframes backgroundFloat {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    33% { transform: translate(-20px, -20px) rotate(1deg); }
    66% { transform: translate(20px, -10px) rotate(-1deg); }
}

@keyframes gridMove {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

body.light-theme .signup-background {
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 212, 255, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(0, 255, 136, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(255, 170, 0, 0.02) 0%, transparent 50%);
}

/* ===================================
   Signup Card
   =================================== */
.signup-container {
    width: 100%;
    max-width: 600px;
    position: relative;
    z-index: 10;
}

.signup-card {
    background: rgba(26, 31, 46, 0.95);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-3xl);
    box-shadow: var(--shadow-large);
    position: relative;
    overflow: hidden;
    transition: var(--transition-base);
}

.signup-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-success));
    border-radius: var(--radius-2xl) var(--radius-2xl) 0 0;
}

.signup-card:hover {
    box-shadow: 
        0 30px 60px rgba(0, 0, 0, 0.4),
        0 0 0 1px rgba(0, 212, 255, 0.1);
}

body.light-theme .signup-card {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 
        0 20px 60px rgba(0, 0, 0, 0.1),
        0 0 0 1px rgba(0, 0, 0, 0.05);
}

/* ===================================
   Signup Header
   =================================== */
.signup-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.signup-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-success));
    border-radius: 50%;
    margin-bottom: var(--spacing-lg);
    animation: pulse 2s ease-in-out infinite;
}

.signup-icon i {
    font-size: var(--font-size-3xl);
    color: var(--bg-primary);
}

.signup-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-success));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.signup-subtitle {
    color: var(--text-secondary);
    font-size: var(--font-size-lg);
}

/* ===================================
   Alert Messages
   =================================== */
.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: var(--transition-base);
    animation: slideInFromTop 0.4s ease-out;
}

@keyframes slideInFromTop {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.alert i {
    font-size: var(--font-size-lg);
}

.alert-success {
    background: rgba(0, 255, 136, 0.1);
    border: 1px solid rgba(0, 255, 136, 0.2);
    color: var(--accent-success);
}

.alert-error {
    background: rgba(255, 71, 87, 0.1);
    border: 1px solid rgba(255, 71, 87, 0.2);
    color: var(--accent-error);
}

.alert-info {
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.2);
    color: var(--accent-primary);
}

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

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

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

.form-group.full-width {
    grid-column: 1 / -1;
}

.form-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.form-label i {
    font-size: var(--font-size-sm);
    color: var(--accent-primary);
}

.form-input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: var(--transition-base);
    outline: none;
}

.form-input::placeholder {
    color: var(--text-tertiary);
}

.form-input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.1);
}

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

/* Password Strength Indicator */
.password-strength {
    height: 4px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    margin-top: var(--spacing-xs);
    overflow: hidden;
    position: relative;
}

.password-strength-fill {
    height: 100%;
    width: 0;
    transition: var(--transition-base);
    border-radius: var(--radius-sm);
}

.password-strength.weak .password-strength-fill {
    width: 33%;
    background: var(--accent-error);
}

.password-strength.medium .password-strength-fill {
    width: 66%;
    background: var(--accent-warning);
}

.password-strength.strong .password-strength-fill {
    width: 100%;
    background: var(--accent-success);
}

.password-hint {
    font-size: var(--font-size-xs);
    color: var(--text-tertiary);
    margin-top: var(--spacing-xs);
}

/* ===================================
   Submit Button
   =================================== */
.btn-primary[type="submit"] {
    width: 100%;
    margin-top: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-xl);
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: var(--bg-primary);
    border: none;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    position: relative;
}

.btn-primary[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 212, 255, 0.3);
}

.btn-primary[type="submit"]:active {
    transform: translateY(0);
}

.btn-loading {
    color: transparent;
    pointer-events: none;
}

.btn-loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin-top: -10px;
    margin-left: -10px;
    border: 2px solid transparent;
    border-top-color: var(--bg-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ===================================
   Signup Footer
   =================================== */
.signup-footer {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-primary);
    text-align: center;
}

.signup-footer p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.signup-footer a {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-base);
}

.signup-footer a:hover {
    color: var(--accent-success);
    text-decoration: underline;
}

/* ===================================
   Mobile Responsive Styles
   =================================== */
@media (max-width: 768px) {
    /* Header mobile styles */
    .mobile-menu-toggle {
        display: flex !important;
    }
    
    .nav-container {
        justify-content: space-between;
        padding: 0 var(--spacing-md);
    }
    
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: var(--bg-primary);
        flex-direction: column;
        justify-content: flex-start;
        align-items: flex-start;
        padding: var(--spacing-2xl);
        transition: var(--transition-base);
        border-top: 1px solid var(--border-primary);
        z-index: 999;
        overflow-y: auto;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-actions {
        display: none !important;
    }
    
    .nav-link {
        width: 100%;
        padding: var(--spacing-md) var(--spacing-sm);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        font-size: var(--font-size-base);
        color: var(--text-primary);
        transition: all 0.2s ease;
    }
    
    .nav-link:hover {
        background: rgba(255, 255, 255, 0.05);
        padding-left: var(--spacing-md);
    }
    
    .nav-link i {
        margin-right: var(--spacing-sm);
        width: 20px;
        color: var(--accent-primary);
    }
    
    .mobile-only-actions {
        display: flex !important;
        flex-direction: column;
        width: 100%;
        margin-top: var(--spacing-lg);
        padding-top: var(--spacing-lg);
        border-top: 1px solid rgba(255, 255, 255, 0.1);
        gap: var(--spacing-md);
    }
    
    .mobile-auth-btn {
        width: 100%;
        padding: var(--spacing-md) var(--spacing-lg) !important;
        background: rgba(255, 255, 255, 0.05) !important;
        color: var(--text-primary);
        border-radius: var(--radius-lg);
        text-align: center;
        font-weight: 600;
        transition: all 0.3s ease;
        border: 1px solid rgba(255, 255, 255, 0.1) !important;
        font-size: var(--font-size-base) !important;
        text-decoration: none;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: var(--spacing-sm);
    }
    
    .mobile-auth-btn:hover {
        background: rgba(255, 255, 255, 0.1) !important;
        transform: translateY(-2px);
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    }
    
    .mobile-auth-btn.primary {
        background: var(--accent-primary) !important;
        color: var(--bg-primary);
        border: none !important;
    }
    
    .mobile-auth-btn.primary:hover {
        background: var(--accent-secondary) !important;
    }
    
    /* Signup mobile styles */
    .signup-wrapper {
        padding: var(--spacing-md);
        padding-top: calc(80px + var(--spacing-xl));
    }
    
    .signup-card {
        padding: var(--spacing-xl);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .signup-title {
        font-size: var(--font-size-2xl);
    }
    
    .signup-subtitle {
        font-size: var(--font-size-sm);
    }
}

@media (max-width: 480px) {
    .signup-card {
        padding: var(--spacing-lg);
    }
    
    .signup-icon {
        width: 60px;
        height: 60px;
    }
    
    .signup-icon i {
        font-size: var(--font-size-xl);
    }
    
    .signup-title {
        font-size: var(--font-size-xl);
    }
}

@media (min-width: 769px) {
    .mobile-menu-toggle {
        display: none !important;
    }
    
    .mobile-only-actions {
        display: none !important;
    }
    
    .nav-menu {
        display: flex !important;
        position: static !important;
        flex-direction: row !important;
        width: auto !important;
        height: auto !important;
        padding: 0 !important;
        box-shadow: none !important;
        background: transparent !important;
        border: none !important;
    }
    
    .nav-actions {
        display: flex !important;
    }
}

/* Focus visible for accessibility */
.form-input:focus-visible,
.btn-primary:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .signup-background {
        animation: none !important;
    }
}