/* ============================================
   MyBacklog - Multi-user SaaS Styles
   Mobile-first responsive design
   ============================================ */

/* CSS Variables */
:root {
    /* Colors */
    --color-primary: #3498DB;
    --color-primary-dark: #2980B9;
    --color-danger: #E74C3C;
    --color-danger-dark: #C0392B;
    --color-success: #27AE60;

    /* Priority Colors */
    --priority-high: #E74C3C;
    --priority-medium: #F39C12;
    --priority-low: #3498DB;

    /* Neutrals */
    --color-bg: #F5F6FA;
    --color-card: #FFFFFF;
    --color-text: #2D3436;
    --color-text-muted: #636E72;
    --color-border: #DFE6E9;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;

    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-full: 50%;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Layout */
    --header-height: 56px;
    --max-width: 600px;
}

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

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.5;
    min-height: 100vh;
    overflow-x: hidden;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-muted {
    color: var(--color-text-muted);
}

/* Screen Container */
.screen {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ============================================
   Landing Page
   ============================================ */
.landing-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-xl);
    text-align: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.landing-hero {
    margin-bottom: var(--spacing-xl);
}

.landing-icon {
    font-size: 4rem;
    display: block;
    margin-bottom: var(--spacing-md);
}

.landing-container h1 {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: white;
    margin-bottom: var(--spacing-md);
}

.landing-tagline {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-sm);
}

.landing-subtitle {
    font-size: var(--font-size-base);
    color: rgba(255, 255, 255, 0.7);
}

.landing-actions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    width: 100%;
    max-width: 300px;
}

.landing-actions .btn {
    width: 100%;
}

.landing-actions .btn-secondary {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.landing-actions .btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.3);
}

/* ============================================
   Auth Screens (Login/Register)
   ============================================ */
.auth-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: var(--spacing-xl);
    max-width: var(--max-width);
    margin: 0 auto;
    width: 100%;
}

.auth-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    position: relative;
}

.auth-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: var(--spacing-md);
}

.auth-header h1 {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-xs);
}

.btn-back {
    position: absolute;
    left: 0;
    top: 0;
    background: none;
    border: none;
    color: var(--color-primary);
    font-size: var(--font-size-base);
    cursor: pointer;
    padding: var(--spacing-sm);
}

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

.auth-switch {
    text-align: center;
    margin-top: var(--spacing-lg);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.auth-switch a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
}

.auth-switch a:hover {
    text-decoration: underline;
}

/* ============================================
   Header
   ============================================ */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--color-card);
    border-bottom: 1px solid var(--color-border);
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 var(--spacing-md);
    gap: var(--spacing-sm);
}

.header-title {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    min-width: 0;
}

.header-title h1 {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.header-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.btn-icon {
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border-radius: var(--radius-full);
    font-size: 1.25rem;
    transition: background-color 0.2s;
    flex-shrink: 0;
}

.btn-icon:hover {
    background-color: var(--color-bg);
}

.btn-icon:active {
    background-color: var(--color-border);
}

/* ============================================
   Filter Tabs
   ============================================ */
.filter-tabs {
    display: flex;
    background-color: var(--color-card);
    border-bottom: 1px solid var(--color-border);
    padding: 0 var(--spacing-md);
}

.filter-tab {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: all 0.2s;
}

.filter-tab.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.filter-tab:hover:not(.active) {
    color: var(--color-text);
}

/* ============================================
   Content Area
   ============================================ */
.content {
    flex: 1;
    padding: var(--spacing-md);
    padding-bottom: calc(var(--spacing-xl) + 60px); /* Space for FAB */
    max-width: var(--max-width);
    margin: 0 auto;
    width: 100%;
}

/* ============================================
   Card List
   ============================================ */
.card-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

/* Product Card */
.product-card {
    background-color: var(--color-card);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    transition: box-shadow 0.2s, transform 0.2s;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.product-card:hover {
    box-shadow: var(--shadow-md);
}

.product-card:active {
    transform: scale(0.98);
}

.product-card-content {
    flex: 1;
    min-width: 0;
}

.product-card-name {
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-xs);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.product-card-url {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.product-card-url::before {
    content: '🔗 ';
}

.product-card-arrow {
    color: var(--color-text-muted);
    font-size: 1.25rem;
    flex-shrink: 0;
}

/* Backlog Item Card */
.item-card {
    background-color: var(--color-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: box-shadow 0.2s;
}

.item-card:hover {
    box-shadow: var(--shadow-md);
}

.item-card.done {
    opacity: 0.7;
}

.item-card.done .item-card-title {
    text-decoration: line-through;
}

.item-card-main {
    display: flex;
    align-items: flex-start;
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
    cursor: pointer;
}

.item-checkbox {
    width: 24px;
    height: 24px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
    margin-top: 2px;
}

.item-checkbox:hover {
    border-color: var(--color-primary);
}

.item-card.done .item-checkbox {
    background-color: var(--color-success);
    border-color: var(--color-success);
    color: white;
}

.item-checkbox-icon {
    display: none;
    font-size: 0.875rem;
}

.item-card.done .item-checkbox-icon {
    display: block;
}

.priority-badge {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-bold);
    color: white;
    flex-shrink: 0;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    text-transform: uppercase;
}

.priority-badge:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

.priority-badge:active {
    transform: scale(0.95);
}

.priority-badge.priority-H {
    background-color: var(--priority-high);
}

.priority-badge.priority-M {
    background-color: var(--priority-medium);
}

.priority-badge.priority-L {
    background-color: var(--priority-low);
}

.item-card-content {
    flex: 1;
    min-width: 0;
}

.item-card-title {
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--spacing-xs);
    word-wrap: break-word;
}

.item-card-notes {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Expanded Item Edit Form */
.item-card-edit {
    display: none;
    padding: var(--spacing-md);
    padding-top: 0;
    border-top: 1px solid var(--color-border);
}

.item-card.expanded .item-card-edit {
    display: block;
}

.item-card-edit .form-group {
    margin-bottom: var(--spacing-sm);
}

.item-card-edit .form-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
    margin-top: var(--spacing-md);
}

/* ============================================
   Empty State
   ============================================ */
.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-muted);
}

.empty-state p {
    margin-bottom: var(--spacing-xs);
}

/* ============================================
   Floating Action Button
   ============================================ */
.fab {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 56px;
    height: 56px;
    border-radius: var(--radius-full);
    background-color: var(--color-primary);
    color: white;
    border: none;
    font-size: 1.75rem;
    font-weight: var(--font-weight-normal);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
}

.fab:hover {
    background-color: var(--color-primary-dark);
    transform: scale(1.05);
}

.fab:active {
    transform: scale(0.95);
}

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

.form-group label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-muted);
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="url"],
textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

textarea {
    resize: vertical;
    min-height: 80px;
}

/* Priority Selector */
.priority-selector {
    display: flex;
    gap: var(--spacing-sm);
}

.priority-option {
    flex: 1;
    padding: var(--spacing-sm);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    background: none;
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-bold);
    cursor: pointer;
    transition: all 0.2s;
}

.priority-option[data-priority="H"] {
    color: var(--priority-high);
}

.priority-option[data-priority="M"] {
    color: var(--priority-medium);
}

.priority-option[data-priority="L"] {
    color: var(--priority-low);
}

.priority-option.active {
    color: white;
}

.priority-option[data-priority="H"].active {
    background-color: var(--priority-high);
    border-color: var(--priority-high);
}

.priority-option[data-priority="M"].active {
    background-color: var(--priority-medium);
    border-color: var(--priority-medium);
}

.priority-option[data-priority="L"].active {
    background-color: var(--priority-low);
    border-color: var(--priority-low);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    min-height: 44px;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-size-lg);
    min-height: 52px;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
}

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

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

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

.btn-danger:hover {
    background-color: var(--color-danger-dark);
}

.btn-full {
    width: 100%;
}

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
    min-height: 36px;
}

/* Error Message */
.error-message {
    color: var(--color-danger);
    font-size: var(--font-size-sm);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background-color: rgba(231, 76, 60, 0.1);
    border-radius: var(--radius-sm);
}

/* ============================================
   Modal
   ============================================ */
.modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: flex-end;
    justify-content: center;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background-color: rgba(0, 0, 0, 0.5);
    opacity: 0;
    transition: opacity 0.2s;
}

.modal:not(.hidden) .modal-backdrop {
    opacity: 1;
}

.modal-content {
    position: relative;
    background-color: var(--color-card);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    width: 100%;
    max-width: var(--max-width);
    max-height: 90vh;
    overflow-y: auto;
    padding: var(--spacing-lg);
    transform: translateY(100%);
    transition: transform 0.3s ease-out;
}

.modal:not(.hidden) .modal-content {
    transform: translateY(0);
}

.modal-small {
    max-width: 400px;
    border-radius: var(--radius-lg);
    margin: auto;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
}

.modal-header h2 {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--color-text-muted);
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    transition: background-color 0.2s;
}

.modal-close:hover {
    background-color: var(--color-bg);
}

.modal-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
    margin-top: var(--spacing-lg);
}

.delete-section {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

/* ============================================
   Loading Overlay
   ============================================ */
.loading-overlay {
    position: fixed;
    inset: 0;
    background-color: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: var(--radius-full);
    animation: spin 0.8s linear infinite;
}

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

/* ============================================
   Animations
   ============================================ */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card-list > * {
    animation: fadeIn 0.3s ease-out;
}

/* ============================================
   Responsive - Tablet and Desktop
   ============================================ */
@media (min-width: 768px) {
    .modal-content {
        border-radius: var(--radius-lg);
        margin: auto;
        max-height: 80vh;
    }

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

    .fab {
        bottom: var(--spacing-xl);
        right: var(--spacing-xl);
    }

    .landing-actions {
        flex-direction: row;
        max-width: 400px;
    }

    .landing-container h1 {
        font-size: 3rem;
    }

    .landing-tagline {
        font-size: var(--font-size-xl);
    }
}

/* ============================================
   Safe Area for iOS
   ============================================ */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
    .content {
        padding-bottom: calc(var(--spacing-xl) + 60px + env(safe-area-inset-bottom));
    }

    .fab {
        bottom: calc(var(--spacing-lg) + env(safe-area-inset-bottom));
    }

    .modal-content {
        padding-bottom: calc(var(--spacing-lg) + env(safe-area-inset-bottom));
    }
}

/* ============================================
   Share Modal
   ============================================ */
.share-preview {
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    max-height: 300px;
    overflow-y: auto;
    font-family: monospace;
    font-size: var(--font-size-sm);
    white-space: pre-wrap;
    word-wrap: break-word;
    line-height: 1.6;
}

.share-actions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.share-actions .btn span {
    margin-right: var(--spacing-xs);
}

/* ============================================
   Toast Notification
   ============================================ */
.toast {
    position: fixed;
    bottom: calc(var(--spacing-lg) + 70px);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background-color: var(--color-text);
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    box-shadow: var(--shadow-lg);
    z-index: 3000;
    opacity: 0;
    transition: transform 0.3s ease-out, opacity 0.3s ease-out;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.hidden {
    display: block;
    visibility: hidden;
}

.toast.show {
    visibility: visible;
}