/* LinkKeep - Main Stylesheet */
/* Professional, Modern, World-Class, Premium, Trusted Design */

/* === CSS Reset & Base === */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Primary Colors - Modern Blue Palette */
    --color-primary: #0066FF;
    --color-primary-dark: #0052CC;
    --color-primary-light: #3385FF;
    --color-primary-subtle: #E6F0FF;

    /* Neutral Colors - Clean White-Based */
    --color-white: #FFFFFF;
    --color-black: #000000;
    --color-gray-50: #FAFBFC;
    --color-gray-100: #F4F5F7;
    --color-gray-200: #EBECF0;
    --color-gray-300: #DFE1E6;
    --color-gray-400: #B3B9C4;
    --color-gray-500: #8993A4;
    --color-gray-600: #6B778C;
    --color-gray-700: #505F79;
    --color-gray-800: #2C3E50;
    --color-gray-900: #172B4D;

    /* Status Colors */
    --color-success: #00B69B;
    --color-success-light: #E7F7F5;
    --color-warning: #F39C12;
    --color-warning-light: #FEF5E7;
    --color-error: #E74C3C;
    --color-error-light: #FADBD8;
    --color-info: #3498DB;
    --color-info-light: #D6EAF8;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-xs: 0.75rem;    /* 12px */
    --font-size-sm: 0.875rem;   /* 14px */
    --font-size-base: 1rem;     /* 16px */
    --font-size-lg: 1.125rem;   /* 18px */
    --font-size-xl: 1.25rem;    /* 20px */
    --font-size-2xl: 1.5rem;    /* 24px */
    --font-size-3xl: 1.875rem;  /* 30px */
    --font-size-4xl: 2.25rem;   /* 36px */

    /* Spacing */
    --spacing-1: 0.25rem;   /* 4px */
    --spacing-2: 0.5rem;    /* 8px */
    --spacing-3: 0.75rem;   /* 12px */
    --spacing-4: 1rem;      /* 16px */
    --spacing-5: 1.25rem;   /* 20px */
    --spacing-6: 1.5rem;    /* 24px */
    --spacing-8: 2rem;      /* 32px */
    --spacing-10: 2.5rem;   /* 40px */
    --spacing-12: 3rem;     /* 48px */
    --spacing-16: 4rem;     /* 64px */

    /* Border Radius */
    --radius-sm: 0.375rem;  /* 6px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.75rem;   /* 12px */
    --radius-xl: 1rem;      /* 16px */
    --radius-2xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;

    /* Shadows - Premium feel */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.03), 0 1px 3px 0 rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.06), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.03);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 10px 10px -5px rgba(0, 0, 0, 0.02);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.12);

    /* Transitions - Smooth Premium Feel */
    --transition-fast: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 350ms cubic-bezier(0.34, 1.56, 0.64, 1);
    --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);

    /* Z-Index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* === Base Styles === */
html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-gray-900);
    background-color: var(--color-white);
    min-height: 100vh;
}

/* === Typography === */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-4);
}

h1 { font-size: var(--font-size-4xl); font-weight: 800; }
h2 { font-size: var(--font-size-3xl); font-weight: 700; }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin-bottom: var(--spacing-4);
    line-height: 1.7;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-6);
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    font-weight: 600;
    line-height: 1.5;
    text-align: center;
    white-space: nowrap;
    border: 1px solid transparent;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-base);
    user-select: none;
    letter-spacing: 0.01em;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px var(--color-primary-subtle);
}

.btn-primary {
    color: var(--color-white);
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-secondary {
    color: var(--color-gray-700);
    background-color: var(--color-white);
    border-color: var(--color-gray-300);
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--color-gray-50);
    border-color: var(--color-gray-400);
    box-shadow: var(--shadow-md);
}

.btn-success {
    color: var(--color-white);
    background-color: var(--color-success);
    border-color: var(--color-success);
    box-shadow: var(--shadow-sm);
}

.btn-success:hover:not(:disabled) {
    background-color: #009688;
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-error {
    color: var(--color-white);
    background-color: var(--color-error);
    border-color: var(--color-error);
    box-shadow: var(--shadow-sm);
}

.btn-error:hover:not(:disabled) {
    background-color: #C0392B;
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-sm {
    padding: var(--spacing-2) var(--spacing-4);
    font-size: var(--font-size-xs);
}

.btn-lg {
    padding: var(--spacing-4) var(--spacing-8);
    font-size: var(--font-size-base);
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-icon {
    padding: var(--spacing-2);
    border-radius: var(--radius-full);
}

/* === Forms === */
.form-group {
    margin-bottom: var(--spacing-5);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-2);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-gray-900);
}

.form-input,
.form-textarea,
.form-select {
    display: block;
    width: 100%;
    padding: var(--spacing-3) var(--spacing-4);
    font-family: var(--font-family);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    color: var(--color-gray-900);
    background-color: var(--color-white);
    border: 1.5px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-subtle);
}

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

.form-textarea {
    resize: vertical;
    min-height: 100px;
}

.form-hint {
    display: block;
    margin-top: var(--spacing-2);
    font-size: var(--font-size-xs);
    color: var(--color-gray-600);
    line-height: 1.5;
}

.form-error {
    color: var(--color-error);
}

.form-success {
    color: var(--color-success);
}

/* Password Strength Indicator */
.password-strength {
    margin-top: var(--spacing-2);
}

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

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

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

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

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

.password-strength-text {
    margin-top: var(--spacing-1);
    font-size: var(--font-size-xs);
    font-weight: 500;
}

/* === Alerts === */
.alert {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-3);
    padding: var(--spacing-4);
    margin-bottom: var(--spacing-4);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-sm);
    border: 1px solid;
}

.alert svg {
    flex-shrink: 0;
    margin-top: 2px;
}

.alert-success {
    color: #065f46;
    background-color: var(--color-success-light);
    border-color: #6ee7b7;
}

.alert-error {
    color: #991b1b;
    background-color: var(--color-error-light);
    border-color: #fecaca;
}

.alert-warning {
    color: #92400e;
    background-color: var(--color-warning-light);
    border-color: #fde68a;
}

.alert-info {
    color: #1e40af;
    background-color: var(--color-info-light);
    border-color: #bfdbfe;
}

/* === Cards === */
.card {
    background-color: var(--color-white);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-gray-200);
    overflow: hidden;
}

.card-header {
    padding: var(--spacing-6);
    border-bottom: 1px solid var(--color-gray-200);
    background-color: var(--color-gray-50);
}

.card-body {
    padding: var(--spacing-6);
}

.card-footer {
    padding: var(--spacing-6);
    border-top: 1px solid var(--color-gray-200);
    background-color: var(--color-gray-50);
}

/* === Utilities === */
.text-muted {
    color: var(--color-gray-500);
}

.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.link {
    color: var(--color-primary);
    font-weight: 500;
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* === Loading Spinner === */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-gray-300);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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

/* === Responsive === */
@media (max-width: 768px) {
    :root {
        --font-size-4xl: 1.875rem;
        --font-size-3xl: 1.5rem;
        --font-size-2xl: 1.25rem;
    }
}