/* ================================================
   MODERN AUTHENTICATION UI - ANIMATIONS & INTERACTIONS
   ================================================ */

:root {
    --color-primary: #2e8b57;
    --color-primary-dark: #1e5631;
    --color-primary-light: #52b788;
    --color-success: #4caf50;
    --color-error: #f44336;
    --color-warning: #ff9800;
    --color-info: #2196f3;
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    --duration-fast: 150ms;
    --duration-base: 300ms;
    --duration-slow: 500ms;
    --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
    --ease-out: cubic-bezier(0, 0, 0.2, 1);
    --ease-in: cubic-bezier(0.4, 0, 1, 1);
}

/* ================================================
   GLOBAL ANIMATIONS
   ================================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(1rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInDown {
    from {
        opacity: 0;
        transform: translateY(-1rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-1rem);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(1rem);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

@keyframes shimmer {
    0% {
        background-position: -1000px 0;
    }
    100% {
        background-position: 1000px 0;
    }
}

@keyframes checkmark {
    0% {
        stroke-dasharray: 60;
        stroke-dashoffset: 60;
    }
    100% {
        stroke-dasharray: 60;
        stroke-dashoffset: 0;
    }
}

/* ================================================
   FORM CONTAINER
   ================================================ */

.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    position: relative;
    overflow: hidden;
    animation: fadeIn var(--duration-base) var(--ease-in-out);
}

.auth-container::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.auth-container::after {
    content: '';
    position: absolute;
    bottom: -50%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
    animation: float 8s ease-in-out infinite 1s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(30px);
    }
}

.auth-card {
    width: 100%;
    max-width: 500px;
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    position: relative;
    z-index: 1;
    animation: slideInUp var(--duration-slow) var(--ease-out);
    overflow: hidden;
}

.auth-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
}

/* ================================================
   FORM HEADER
   ================================================ */

.auth-header {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
    padding: var(--spacing-2xl);
    text-align: center;
    animation: slideInDown var(--duration-base) var(--ease-out);
}

.auth-header h1 {
    font-size: 1.875rem;
    font-weight: 700;
    margin: 0;
    letter-spacing: -0.5px;
}

.auth-header p {
    font-size: 0.875rem;
    opacity: 0.9;
    margin: var(--spacing-sm) 0 0 0;
}

.auth-header svg {
    display: inline-block;
    margin-right: var(--spacing-md);
    animation: slideInRight var(--duration-base) var(--ease-out);
}

/* ================================================
   FORM BODY
   ================================================ */

.auth-body {
    padding: var(--spacing-2xl);
    animation: slideInUp var(--duration-base) var(--ease-out) 100ms both;
}

.form-group {
    margin-bottom: var(--spacing-lg);
    animation: slideInUp var(--duration-base) var(--ease-out);
}

.form-group:nth-child(1) { animation-delay: 100ms; }
.form-group:nth-child(2) { animation-delay: 150ms; }
.form-group:nth-child(3) { animation-delay: 200ms; }
.form-group:nth-child(4) { animation-delay: 250ms; }
.form-group:nth-child(5) { animation-delay: 300ms; }
.form-group:nth-child(6) { animation-delay: 350ms; }

.form-label {
    display: block;
    font-weight: 600;
    color: var(--color-gray-700);
    margin-bottom: var(--spacing-sm);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    transition: color var(--duration-fast) var(--ease-in-out);
}

.form-label svg {
    margin-right: var(--spacing-sm);
    color: var(--color-primary);
}

.form-group:focus-within .form-label {
    color: var(--color-primary);
}

/* ================================================
   FORM INPUTS
   ================================================ */

.form-input,
.form-select {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    border: 2px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-family: inherit;
    transition: all var(--duration-fast) var(--ease-in-out);
    background-color: var(--color-gray-50);
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--color-primary);
    background-color: white;
    box-shadow: 0 0 0 3px rgba(46, 139, 87, 0.1);
}

.form-input::placeholder {
    color: var(--color-gray-400);
}

.form-input:invalid:not(:placeholder-shown),
.form-input.is-invalid {
    border-color: var(--color-error);
    background-color: rgba(244, 67, 54, 0.05);
}

.form-input:valid:not(:placeholder-shown) {
    border-color: var(--color-success);
    background-color: rgba(76, 175, 80, 0.05);
}

.form-select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%232e8b57' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--spacing-lg) center;
    padding-right: var(--spacing-2xl);
}

/* ================================================
   PASSWORD STRENGTH INDICATOR
   ================================================ */

.password-strength {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.strength-bar {
    flex: 1;
    height: 4px;
    background-color: var(--color-gray-200);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.strength-bar.weak {
    background-color: var(--color-error);
}

.strength-bar.fair {
    background-color: var(--color-warning);
}

.strength-bar.good {
    background-color: var(--color-info);
}

.strength-bar.strong {
    background-color: var(--color-success);
}

.strength-text {
    font-size: 0.75rem;
    font-weight: 600;
    margin-top: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* ================================================
   VALIDATION MESSAGES
   ================================================ */

.error-message,
.success-message,
.info-message {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-lg);
    animation: slideInUp var(--duration-base) var(--ease-out);
}

.error-message {
    background-color: rgba(244, 67, 54, 0.1);
    color: var(--color-error);
    border-left: 4px solid var(--color-error);
}

.success-message {
    background-color: rgba(76, 175, 80, 0.1);
    color: var(--color-success);
    border-left: 4px solid var(--color-success);
}

.info-message {
    background-color: rgba(33, 150, 243, 0.1);
    color: var(--color-info);
    border-left: 4px solid var(--color-info);
}

.error-message svg,
.success-message svg,
.info-message svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    margin-top: 2px;
}

.error-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.error-list li {
    margin-bottom: var(--spacing-xs);
}

.error-list li::before {
    content: '✓ ';
    margin-right: var(--spacing-sm);
}

/* ================================================
   BUTTONS
   ================================================ */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--duration-fast) var(--ease-in-out);
    text-decoration: none;
    white-space: nowrap;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width var(--duration-base) var(--ease-out), height var(--duration-base) var(--ease-out);
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
    width: 100%;
    box-shadow: 0 4px 15px rgba(46, 139, 87, 0.3);
    animation: slideInUp var(--duration-base) var(--ease-out) 200ms both;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(46, 139, 87, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 10px rgba(46, 139, 87, 0.3);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-secondary {
    background-color: var(--color-gray-100);
    color: var(--color-gray-700);
}

.btn-secondary:hover {
    background-color: var(--color-gray-200);
}

.btn-link {
    background: none;
    color: var(--color-primary);
    padding: 0;
    font-weight: 500;
}

.btn-link:hover {
    text-decoration: underline;
}

.btn-small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

/* ================================================
   LOADING STATE
   ================================================ */

.btn.loading {
    position: relative;
    color: transparent;
}

.btn.loading::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    top: 50%;
    left: 50%;
    margin-left: -8px;
    margin-top: -8px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin var(--duration-slow) linear infinite;
}

/* ================================================
   LINKS & FOOTER
   ================================================ */

.auth-footer {
    padding: var(--spacing-lg) var(--spacing-2xl);
    text-align: center;
    border-top: 1px solid var(--color-gray-200);
    font-size: 0.875rem;
    color: var(--color-gray-600);
    animation: slideInUp var(--duration-base) var(--ease-out) 300ms both;
}

.auth-footer a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    transition: color var(--duration-fast) var(--ease-in-out);
}

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

/* ================================================
   ACCESSIBILITY
   ================================================ */

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ================================================
   FOCUS VISIBLE
   ================================================ */

.form-input:focus-visible,
.form-select:focus-visible,
.btn:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* ================================================
   RESPONSIVE
   ================================================ */

@media (max-width: 640px) {
    .auth-container {
        padding: var(--spacing-md);
    }

    .auth-card {
        max-width: 100%;
    }

    .auth-header {
        padding: var(--spacing-xl);
    }

    .auth-header h1 {
        font-size: 1.5rem;
    }

    .auth-body {
        padding: var(--spacing-lg);
    }

    .form-input,
    .form-select {
        font-size: 16px;
        padding: var(--spacing-md) var(--spacing-md);
    }

    .btn {
        padding: var(--spacing-md);
        font-size: 0.95rem;
    }
}

/* ================================================
   FOCUS VISIBLE ACCESSIBILITY
   ================================================ */

input:focus-visible,
select:focus-visible,
textarea:focus-visible,
button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}