/* ==========================================================================
   PPP - Global Styles
   Mobile-first, responsive layout with CSS custom properties.
   No CSS framework — plain CSS.

   Theming: dark mode is the DEFAULT. Light mode is applied by setting
   data-theme="light" on <html>. See js/theme.js.
   ========================================================================== */

/* --- CSS Custom Properties (Design Tokens) ---
   Strategy: keep structural tokens (spacing, typography, radii) shared, and
   define color tokens per-theme. Dark is the root default. */

:root {
    /* Brand colors — shared across themes (used on header, buttons) */
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-primary-light: rgba(59, 130, 246, 0.25); /* focus ring */
    --color-success: #22c55e;
    --color-danger: #ef4444;
    --color-danger-hover: #dc2626;
    --color-warning: #f59e0b;

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

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;

    /* Borders */
    --border-radius: 0.5rem;
    --border-radius-sm: 0.25rem;
    --border-width: 1px;

    /* Layout */
    --header-height: 56px;
    --max-content-width: 1024px;

    /* Transitions */
    --transition: 150ms ease;

    /* Theme color tokens — DARK (default) */
    color-scheme: dark;
    --color-bg: #0f172a;            /* slate-900 */
    --color-surface: #1e293b;       /* slate-800 */
    --color-surface-hover: #334155; /* slate-700 */
    --color-border: #334155;        /* slate-700 */
    --color-text: #f1f5f9;          /* slate-100 */
    --color-text-muted: #94a3b8;    /* slate-400 */
    --color-text-light: #64748b;    /* slate-500 */
    --color-on-primary: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.5);
    --header-bg: var(--color-primary);
}

/* --- LIGHT THEME --- */
[data-theme="light"] {
    color-scheme: light;
    --color-bg: #f8fafc;            /* slate-50 */
    --color-surface: #ffffff;
    --color-surface-hover: #f1f5f9; /* slate-100 */
    --color-border: #e2e8f0;        /* slate-200 */
    --color-text: #0f172a;          /* slate-900 */
    --color-text-muted: #64748b;    /* slate-500 */
    --color-text-light: #94a3b8;    /* slate-400 */
    --color-on-primary: #ffffff;
    --color-primary-light: #dbeafe; /* blue-100 focus ring */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --header-bg: var(--color-primary);
}

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

html {
    font-size: var(--font-size-base);
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.5;
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
}

/* --- Header / Navigation --- */
.app-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    height: var(--header-height);
    padding: 0 var(--space-md);
    background-color: var(--header-bg);
    color: var(--color-on-primary);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.app-header__brand {
    display: flex;
    align-items: baseline;
    gap: var(--space-sm);
    flex-shrink: 0;
}

.app-header__title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    letter-spacing: -0.025em;
}

.app-header__subtitle {
    font-size: var(--font-size-sm);
    opacity: 0.8;
    display: none; /* hidden on mobile, shown on larger screens */
}

.app-header__actions {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

/* --- Sync Status Button (click to force sync) --- */
.app-header__status {
    font-size: var(--font-size-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    /* Minimum 44px touch target for mobile accessibility (Apple/Material guidelines) */
    min-height: 44px;
    border-radius: var(--border-radius-sm);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    color: var(--color-text-muted);
    white-space: nowrap;
    cursor: pointer;
    font-family: inherit;
    transition: color var(--transition), border-color var(--transition),
                background var(--transition);
}

.app-header__status:hover:not(:disabled) {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.app-header__status:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* While syncing: disable interaction and keep the pulse animation */
.app-header__status:disabled {
    cursor: default;
    opacity: 0.85;
}

.app-header__status__dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-text-light);
    flex-shrink: 0;
    transition: background var(--transition);
}

/* State: syncing (blue, with pulse) */
.app-header__status--syncing {
    color: var(--color-primary);
    border-color: var(--color-primary);
}
.app-header__status--syncing .app-header__status__dot {
    background: var(--color-primary);
    animation: sync-pulse 1s ease-in-out infinite;
}

/* State: synced / idle (green) */
.app-header__status--idle .app-header__status__dot {
    background: var(--color-success);
}

/* State: offline (gray) */
.app-header__status--offline {
    color: var(--color-text-light);
}
.app-header__status--offline .app-header__status__dot {
    background: var(--color-text-light);
}

/* State: error (red) */
.app-header__status--error {
    color: var(--color-danger);
    border-color: var(--color-danger);
}
.app-header__status--error .app-header__status__dot {
    background: var(--color-danger);
}

@keyframes sync-pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.3); }
}

/* --- Theme Toggle Button --- */
.theme-toggle {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--border-radius-sm);
    color: var(--color-on-primary);
    cursor: pointer;
    transition: var(--transition);
}

.theme-toggle:hover {
    background-color: rgba(255, 255, 255, 0.15);
}

.theme-toggle:active {
    transform: scale(0.95);
}

.theme-toggle__icon {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

/* Show the relevant icon based on the active theme */
.theme-toggle__icon--sun {
    display: none; /* hidden in dark mode; shown in light mode */
}

[data-theme="light"] .theme-toggle__icon--moon {
    display: none;
}

[data-theme="light"] .theme-toggle__icon--sun {
    display: block;
}

/* Desktop tab navigation — hidden on mobile */
.app-nav--tabs {
    display: none;
}

.app-nav--tabs .app-nav__tab {
    background: transparent;
    border: none;
    color: var(--color-on-primary);
    opacity: 0.7;
    font-size: var(--font-size-base);
    font-family: inherit;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.app-nav--tabs .app-nav__tab:hover:not(:disabled) {
    opacity: 1;
    background-color: rgba(255, 255, 255, 0.1);
}

.app-nav--tabs .app-nav__tab--active {
    opacity: 1;
    background-color: rgba(255, 255, 255, 0.15);
    font-weight: 600;
}

.app-nav--tabs .app-nav__tab:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Mobile dropdown navigation — shown on mobile */
.app-nav--dropdown {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.app-nav--dropdown .app-nav__label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

.app-nav--dropdown .app-nav__select {
    background-color: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: var(--color-on-primary);
    font-size: var(--font-size-sm);
    font-family: inherit;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
}

.app-nav--dropdown .app-nav__select option {
    color: var(--color-text);
    background-color: var(--color-surface);
}

/* --- Main Content --- */
.app-main {
    flex: 1;
    width: 100%;
    max-width: var(--max-content-width);
    margin: 0 auto;
    padding: var(--space-md);
}

/* --- Module Views --- */
.module-view {
    display: none;
    animation: fadeIn var(--transition);
}

.module-view--active {
    display: block;
}

.module-placeholder {
    text-align: center;
    padding: var(--space-xl) var(--space-md);
    color: var(--color-text-muted);
}

.module-placeholder h2 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

/* --- Login View (Phase 2) --- */
.login-view {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
    padding: var(--space-xl) var(--space-md);
}

.login-card {
    background-color: var(--color-surface);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    padding: var(--space-xl);
    max-width: 400px;
    width: 100%;
    text-align: center;
}

.login-card__logo {
    margin-bottom: var(--space-md);
}

.login-card__logo img {
    border-radius: var(--border-radius);
}

.login-card__title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-sm);
}

.login-card__text {
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
    font-size: var(--font-size-sm);
}

.login-card__buttons {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

/* OAuth provider buttons */
.auth-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-base);
    font-family: inherit;
    font-weight: 500;
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius-sm);
    background-color: var(--color-surface);
    color: var(--color-text);
    cursor: pointer;
    transition: var(--transition);
}

.auth-btn:hover:not(:disabled) {
    background-color: var(--color-surface-hover);
    border-color: var(--color-text-muted);
}

.auth-btn:active:not(:disabled) {
    transform: scale(0.98);
}

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

.auth-btn__icon {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

/* GitHub button — dark icon container in both themes for brand consistency */
.auth-btn--github {
    background-color: #24292e;
    color: #ffffff;
    border-color: #24292e;
}

.auth-btn--github:hover:not(:disabled) {
    background-color: #2f363d;
    border-color: #2f363d;
}

/* --- Auth Form (email/password) --- */
.auth-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    text-align: left;
}

.auth-form__field {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.auth-form__label {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-muted);
}

.auth-form__input {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-base);
    font-family: inherit;
    color: var(--color-text);
    background-color: var(--color-bg);
    border: var(--border-width) solid var(--color-border);
    border-radius: var(--border-radius-sm);
    transition: var(--transition);
}

.auth-form__input::placeholder {
    color: var(--color-text-light);
}

.auth-form__input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.auth-form__submit {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    margin-top: var(--space-sm);
    font-size: var(--font-size-base);
    font-family: inherit;
    font-weight: 600;
    color: var(--color-on-primary);
    background-color: var(--color-primary);
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.auth-form__submit:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
}

.auth-form__submit:active:not(:disabled) {
    transform: scale(0.98);
}

.auth-form__submit:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* --- Sign in / Sign up toggle --- */
.login-card__toggle {
    margin-top: var(--space-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.login-card__toggle-btn {
    background: none;
    border: none;
    padding: 0;
    margin-left: var(--space-xs);
    font-family: inherit;
    font-size: inherit;
    font-weight: 600;
    color: var(--color-primary);
    cursor: pointer;
    text-decoration: underline;
}

.login-card__toggle-btn:hover:not(:disabled) {
    color: var(--color-primary-hover);
}

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

.login-card__error {
    color: var(--color-danger);
    font-size: var(--font-size-sm);
    margin-top: var(--space-md);
    padding: var(--space-sm) var(--space-md);
    background-color: rgba(239, 68, 68, 0.1);
    border-radius: var(--border-radius-sm);
}

.login-card__loading {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin-top: var(--space-md);
}

.login-card__hint {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-top: var(--space-lg);
}

/* --- User Menu (header) --- */
.user-menu {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.user-menu__email {
    font-size: var(--font-size-sm);
    opacity: 0.9;
    max-width: 140px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.user-menu__signout {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--border-radius-sm);
    color: var(--color-on-primary);
    cursor: pointer;
    transition: var(--transition);
}

.user-menu__signout:hover {
    background-color: rgba(255, 255, 255, 0.15);
}

.user-menu__signout:active {
    transform: scale(0.95);
}

/* --- No-JS Fallback --- */
.noscript-message {
    text-align: center;
    padding: var(--space-xl);
    margin: var(--space-xl);
    background-color: var(--color-surface);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.noscript-message h2 {
    color: var(--color-danger);
    margin-bottom: var(--space-sm);
}

/* --- Utility --- */
[hidden] {
    display: none !important;
}

/* --- Animations --- */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ==========================================================================
   Responsive Breakpoints
   Mobile-first: base styles above are for mobile.
   Enhancements for larger screens below.
   ========================================================================== */

/* Tablet and up (768px+) */
@media (min-width: 768px) {
    .app-header__subtitle {
        display: inline;
    }

    /* Switch from dropdown to tab navigation */
    .app-nav--dropdown {
        display: none;
    }

    .app-nav--tabs {
        display: flex;
        gap: var(--space-xs);
    }

    .app-main {
        padding: var(--space-lg);
    }
}

/* Desktop and up (1024px+) */
@media (min-width: 1024px) {
    :root {
        --header-height: 64px;
    }

    .app-main {
        padding: var(--space-xl);
    }
}

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