/* ==========================================================================
   Vercel-Inspired Design System — TaskMaster Pro
   Based on DESIGN.md: Stark black-ink on near-white canvas, mesh gradient
   accents, Geist/Inter typography, stacked shadows, pill CTAs.
   ========================================================================== */

/* ---------- Google Fonts loaded via <link> in index.html ---------- */

/* ==========================================================================
   CSS Custom Properties (Design Tokens from DESIGN.md)
   ========================================================================== */
:root {
    /* ── Colors ── */
    --color-primary:          #171717;
    --color-on-primary:       #ffffff;
    --color-ink:              #171717;
    --color-body:             #4d4d4d;
    --color-mute:             #888888;
    --color-hairline:         #ebebeb;
    --color-hairline-strong:  #a1a1a1;
    --color-canvas:           #ffffff;
    --color-canvas-soft:      #fafafa;
    --color-canvas-soft-2:    #f5f5f5;
    --color-link:             #0070f3;
    --color-link-deep:        #0761d1;
    --color-link-bg-soft:     #d3e5ff;
    --color-success:          #0070f3;
    --color-error:            #ee0000;
    --color-error-soft:       #f7d4d6;
    --color-warning:          #f5a623;
    --color-warning-soft:     #ffefcf;
    --color-violet:           #7928ca;
    --color-cyan:             #50e3c2;
    --color-highlight-pink:   #ff0080;

    /* Gradient pairs */
    --grad-develop-start:     #007cf0;
    --grad-develop-end:       #00dfd8;
    --grad-preview-start:     #7928ca;
    --grad-preview-end:       #ff0080;
    --grad-ship-start:        #ff4d4d;
    --grad-ship-end:          #f9cb28;

    /* Selection */
    --selection-bg:           #171717;
    --selection-fg:           #f2f2f2;

    /* ── Typography ── */
    --font-sans:   'Inter', system-ui, -apple-system, sans-serif;
    --font-mono:   'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, monospace;

    /* ── Rounded ── */
    --rounded-none:     0px;
    --rounded-xs:       4px;
    --rounded-sm:       6px;
    --rounded-md:       8px;
    --rounded-lg:       12px;
    --rounded-xl:       16px;
    --rounded-pill-sm:  64px;
    --rounded-pill:     100px;
    --rounded-full:     9999px;

    /* ── Spacing ── */
    --space-xxs:  4px;
    --space-xs:   8px;
    --space-sm:   12px;
    --space-md:   16px;
    --space-lg:   24px;
    --space-xl:   32px;
    --space-2xl:  40px;
    --space-3xl:  48px;
    --space-4xl:  64px;
    --space-5xl:  96px;

    /* ── Elevation (stacked shadows) ── */
    --shadow-level-1: inset 0 0 0 1px rgba(0,0,0,0.08);
    --shadow-level-2: 0px 1px 1px rgba(0,0,0,0.02), 0px 2px 2px rgba(0,0,0,0.04), inset 0 0 0 1px rgba(0,0,0,0.08);
    --shadow-level-3: 0px 2px 2px rgba(0,0,0,0.04), 0px 8px 8px -8px rgba(0,0,0,0.04), inset 0 0 0 1px rgba(0,0,0,0.08);
    --shadow-level-4: 0px 2px 2px rgba(0,0,0,0.04), 0px 8px 16px -4px rgba(0,0,0,0.04), inset 0 0 0 1px rgba(0,0,0,0.08);
    --shadow-level-5: 0px 1px 1px rgba(0,0,0,0.02), 0px 8px 16px -4px rgba(0,0,0,0.04), 0px 24px 32px -8px rgba(0,0,0,0.06), inset 0 0 0 1px rgba(0,0,0,0.08);

    /* ── Transition ── */
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);

    /* ── Category semantic colors ── */
    --cat-work:     #0070f3;
    --cat-personal: #7928ca;
    --cat-study:    #ff0080;
    --cat-health:   #50e3c2;
    --cat-other:    #f5a623;
}

/* ==========================================================================
   Dark Theme (Polarity-Flipped — ink surface, white text)
   ========================================================================== */
[data-theme="dark"] {
    --color-primary:          #ffffff;
    --color-on-primary:       #171717;
    --color-ink:              #ededed;
    --color-body:             #a1a1a1;
    --color-mute:             #6e6e6e;
    --color-hairline:         #2e2e2e;
    --color-hairline-strong:  #454545;
    --color-canvas:           #0a0a0a;
    --color-canvas-soft:      #111111;
    --color-canvas-soft-2:    #1a1a1a;
    --color-link:             #3291ff;
    --color-link-deep:        #5ba2ff;
    --color-error:            #ff4d4d;
    --color-error-soft:       #3d1417;
    --color-warning:          #f5a623;
    --color-warning-soft:     #3d2e0b;

    --selection-bg:           #f2f2f2;
    --selection-fg:           #171717;

    --shadow-level-1: inset 0 0 0 1px rgba(255,255,255,0.06);
    --shadow-level-2: 0px 1px 1px rgba(0,0,0,0.12), 0px 2px 2px rgba(0,0,0,0.1), inset 0 0 0 1px rgba(255,255,255,0.06);
    --shadow-level-3: 0px 2px 2px rgba(0,0,0,0.1), 0px 8px 8px -8px rgba(0,0,0,0.1), inset 0 0 0 1px rgba(255,255,255,0.06);
    --shadow-level-4: 0px 2px 2px rgba(0,0,0,0.1), 0px 8px 16px -4px rgba(0,0,0,0.1), inset 0 0 0 1px rgba(255,255,255,0.06);
    --shadow-level-5: 0px 1px 1px rgba(0,0,0,0.12), 0px 8px 16px -4px rgba(0,0,0,0.1), 0px 24px 32px -8px rgba(0,0,0,0.16), inset 0 0 0 1px rgba(255,255,255,0.06);
}

/* ==========================================================================
   Selection
   ========================================================================== */
::selection {
    background: var(--selection-bg);
    color: var(--selection-fg);
}

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

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    font-weight: 400;
    line-height: 24px;
    background-color: var(--color-canvas-soft);
    color: var(--color-ink);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Custom Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
    background: var(--color-hairline-strong);
    border-radius: var(--rounded-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--color-mute); }

/* ==========================================================================
   Typography
   ========================================================================== */
h1 {
    font-family: var(--font-sans);
    font-size: 48px;
    font-weight: 600;
    line-height: 48px;
    letter-spacing: -2.4px;
    color: var(--color-ink);
}

h2 {
    font-family: var(--font-sans);
    font-size: 24px;
    font-weight: 600;
    line-height: 32px;
    letter-spacing: -0.96px;
    color: var(--color-ink);
}

h3 {
    font-family: var(--font-sans);
    font-size: 20px;
    font-weight: 600;
    line-height: 28px;
    letter-spacing: -0.6px;
    color: var(--color-ink);
}

p {
    font-size: 16px;
    font-weight: 400;
    line-height: 24px;
    color: var(--color-body);
}

/* ==========================================================================
   Utilities
   ========================================================================== */
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-danger  { color: var(--color-error); }

.gradient-text {
    background: linear-gradient(
        90deg,
        var(--grad-develop-start),
        var(--grad-develop-end),
        var(--grad-preview-start),
        var(--grad-preview-end)
    );
    background-size: 200% 100%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 4s ease infinite;
}

/* ==========================================================================
   Container
   ========================================================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-xl) var(--space-lg);
}

/* ==========================================================================
   Hero Band (DESIGN.md: hero-band with mesh gradient backdrop)
   ========================================================================== */
.hero-band {
    position: relative;
    background: var(--color-canvas);
    border-radius: var(--rounded-lg);
    box-shadow: var(--shadow-level-4);
    padding: var(--space-4xl) var(--space-xl) var(--space-xl);
    margin-bottom: var(--space-lg);
    overflow: hidden;
    transition: background-color 0.3s ease;
}

/* Mesh gradient atmospheric backdrop */
.hero-gradient-bg {
    position: absolute;
    top: -50%;
    left: -25%;
    right: -25%;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 60% at 30% 20%, rgba(0, 124, 240, 0.12), transparent 60%),
        radial-gradient(ellipse 60% 50% at 70% 30%, rgba(0, 223, 216, 0.10), transparent 50%),
        radial-gradient(ellipse 50% 40% at 50% 50%, rgba(121, 40, 202, 0.08), transparent 50%),
        radial-gradient(ellipse 70% 50% at 60% 40%, rgba(255, 0, 128, 0.06), transparent 60%),
        radial-gradient(ellipse 40% 30% at 40% 60%, rgba(255, 77, 77, 0.05), transparent 50%),
        radial-gradient(ellipse 50% 40% at 70% 70%, rgba(249, 203, 40, 0.04), transparent 50%);
    pointer-events: none;
    animation: heroGradientFloat 12s ease-in-out infinite;
    z-index: 0;
}

[data-theme="dark"] .hero-gradient-bg {
    background:
        radial-gradient(ellipse 80% 60% at 30% 20%, rgba(0, 124, 240, 0.18), transparent 60%),
        radial-gradient(ellipse 60% 50% at 70% 30%, rgba(0, 223, 216, 0.14), transparent 50%),
        radial-gradient(ellipse 50% 40% at 50% 50%, rgba(121, 40, 202, 0.12), transparent 50%),
        radial-gradient(ellipse 70% 50% at 60% 40%, rgba(255, 0, 128, 0.10), transparent 60%),
        radial-gradient(ellipse 40% 30% at 40% 60%, rgba(255, 77, 77, 0.08), transparent 50%),
        radial-gradient(ellipse 50% 40% at 70% 70%, rgba(249, 203, 40, 0.06), transparent 50%);
}

@keyframes heroGradientFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33%      { transform: translate(2%, -2%) scale(1.02); }
    66%      { transform: translate(-1%, 1%) scale(0.99); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    margin-bottom: var(--space-xl);
}

/* Mono eyebrow — caption-mono from DESIGN.md */
.hero-eyebrow {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    color: var(--color-mute);
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: var(--space-md);
    padding: var(--space-xxs) var(--space-sm);
    background: var(--color-canvas-soft);
    border: 1px solid var(--color-hairline);
    border-radius: var(--rounded-full);
}

/* Display-xl headline — sentence-case, period-implied */
.hero-headline {
    font-family: var(--font-sans);
    font-size: 48px;
    font-weight: 600;
    line-height: 48px;
    letter-spacing: -2.4px;
    color: var(--color-ink);
    margin-bottom: var(--space-md);
}

.hero-body {
    font-family: var(--font-sans);
    font-size: 18px;
    font-weight: 400;
    line-height: 28px;
    color: var(--color-body);
    max-width: 520px;
    margin: 0 auto;
}

/* Responsive hero */
@media (max-width: 768px) {
    .hero-band {
        padding: var(--space-3xl) var(--space-md) var(--space-lg);
    }

    .hero-headline {
        font-size: 32px;
        line-height: 40px;
        letter-spacing: -1.28px;
    }

    .hero-body {
        font-size: 16px;
        line-height: 24px;
    }
}

/* ==========================================================================
   Card System (Stacked Shadows + Hairline)
   ========================================================================== */
.card {
    background: var(--color-canvas);
    border-radius: var(--rounded-md);
    box-shadow: var(--shadow-level-3);
    padding: var(--space-lg);
    margin-bottom: var(--space-lg);
    transition: transform var(--transition), box-shadow var(--transition), background-color 0.3s ease;
    position: relative;
}

.card:hover {
    box-shadow: var(--shadow-level-4);
}

/* glass class now just adds a subtle top accent */
.card.glass {
    overflow: hidden;
}

.card.glass::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(
        90deg,
        var(--grad-develop-start),
        var(--grad-develop-end),
        var(--grad-preview-start),
        var(--grad-preview-end),
        var(--grad-ship-start),
        var(--grad-ship-end)
    );
    opacity: 0.6;
    transition: opacity var(--transition);
}

.card.glass:hover::after {
    opacity: 1;
}

/* ==========================================================================
   Header (nav-bar from DESIGN.md)
   ========================================================================== */
.app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--color-canvas);
    border-bottom: 1px solid var(--color-hairline);
    height: 64px;
    display: flex;
    align-items: center;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

[data-theme="dark"] .app-header {
    background: var(--color-canvas);
    border-bottom-color: var(--color-hairline);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.logo-text {
    font-family: var(--font-sans);
    font-size: 20px;
    font-weight: 600;
    line-height: 28px;
    letter-spacing: -0.6px;
    color: var(--color-ink);
}

.logo-icon {
    font-size: 1.25rem;
    animation: float 3s ease-in-out infinite;
}

/* Theme Switch — Vercel-style minimal toggle */
.theme-switch {
    background: var(--color-canvas-soft-2);
    border: 1px solid var(--color-hairline);
    border-radius: var(--rounded-full);
    padding: 3px 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 64px;
    height: 32px;
    position: relative;
    transition: background-color var(--transition), border-color var(--transition);
}

.theme-switch:hover {
    border-color: var(--color-hairline-strong);
}

.theme-switch .icon {
    font-size: 0.9rem;
    z-index: 1;
    transition: opacity var(--transition);
}

.theme-switch::after {
    content: '';
    position: absolute;
    width: 26px;
    height: 26px;
    background: var(--color-primary);
    border-radius: var(--rounded-full);
    top: 2px;
    left: 3px;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

[data-theme="dark"] .theme-switch::after {
    transform: translateX(32px);
}

.theme-switch .toggling {
    animation: none;
}

/* ==========================================================================
   Dashboard Stats
   ========================================================================== */
.dashboard {
    background: var(--color-canvas);
    border-radius: var(--rounded-lg);
    padding: var(--space-xl);
}

.stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
    position: relative;
    z-index: 1;
}

.stat-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-lg);
    background: var(--color-canvas-soft);
    border-radius: var(--rounded-md);
    border: 1px solid var(--color-hairline);
    transition: border-color var(--transition), transform var(--transition);
}

.stat-box:hover {
    border-color: var(--color-hairline-strong);
    transform: translateY(-2px);
}

.stat-label {
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    color: var(--color-mute);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-family: var(--font-sans);
    font-size: 32px;
    font-weight: 600;
    line-height: 40px;
    letter-spacing: -1.28px;
    color: var(--color-ink);
}

.stat-value.text-success { color: var(--color-success); }
.stat-value.text-warning { color: var(--color-warning); }

/* ==========================================================================
   Task Manager Content Layout
   ========================================================================== */
.task-manager-content {
    margin-top: var(--space-xs);
}

.task-manager-inner {
    display: flex;
    flex-direction: column;
    gap: 0;
}

/* ==========================================================================
   Forms & Inputs (form-input from DESIGN.md)
   ========================================================================== */
#task-creation h2 {
    font-size: 20px;
    font-weight: 600;
    line-height: 28px;
    letter-spacing: -0.6px;
    margin-bottom: var(--space-lg);
}

.form-group {
    margin-bottom: var(--space-md);
    width: 100%;
}

.form-row {
    display: flex;
    gap: var(--space-md);
    align-items: flex-end;
}

input[type="text"],
select {
    width: 100%;
    padding: 0 var(--space-sm);
    height: 40px;
    background: var(--color-canvas);
    border: 1px solid var(--color-hairline);
    border-radius: var(--rounded-sm);
    color: var(--color-ink);
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 400;
    line-height: 20px;
    letter-spacing: -0.28px;
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

input[type="text"]::placeholder {
    color: var(--color-mute);
}

input[type="text"]:focus,
select:focus {
    border-color: var(--color-ink);
    box-shadow: 0 0 0 1px var(--color-ink);
}

select {
    cursor: pointer;
    appearance: none;
    padding-right: 36px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%23888888'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    background-size: 16px;
}

/* ==========================================================================
   Buttons (Vercel pill system from DESIGN.md)
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    border: none;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 500;
    line-height: 20px;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn:active {
    transform: scale(0.97);
}

/* Primary CTA — black pill */
.btn-primary {
    background: var(--color-primary);
    color: var(--color-on-primary);
    border-radius: var(--rounded-pill);
    padding: 0 var(--space-lg);
    height: 40px;
    font-size: 14px;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        90deg,
        var(--grad-develop-start),
        var(--grad-develop-end),
        var(--grad-preview-start),
        var(--grad-preview-end)
    );
    opacity: 0;
    transition: opacity 0.3s ease;
    border-radius: inherit;
}

.btn-primary:hover::before {
    opacity: 1;
}

.btn-primary:hover {
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

/* Danger — subtle red */
.btn-danger {
    background: var(--color-canvas);
    color: var(--color-error);
    border: 1px solid var(--color-error-soft);
    border-radius: var(--rounded-pill);
    padding: 0 var(--space-md);
    height: 32px;
    font-size: 14px;
}

.btn-danger:hover {
    background: var(--color-error);
    color: var(--color-on-primary);
    border-color: var(--color-error);
}

.btn-sm {
    height: 32px;
    padding: 0 var(--space-sm);
    font-size: 14px;
}

/* ==========================================================================
   Controls Bar (Search & Filter)
   ========================================================================== */
.controls-bar {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
    padding: var(--space-md);
    background: var(--color-canvas);
    border-radius: var(--rounded-md);
    box-shadow: var(--shadow-level-2);
}

.search-box {
    flex: 1;
    min-width: 200px;
}

.search-box input[type="text"] {
    height: 36px;
    font-size: 14px;
    background: var(--color-canvas-soft);
    border-color: var(--color-hairline);
}

.search-box input[type="text"]:focus {
    background: var(--color-canvas);
}

.filters {
    display: flex;
    gap: var(--space-xs);
    flex-wrap: wrap;
}

/* Filter pills — tab-ghost pattern */
.filter-btn {
    background: var(--color-canvas-soft);
    border: 1px solid var(--color-hairline);
    color: var(--color-body);
    padding: 0 var(--space-md);
    height: 32px;
    border-radius: var(--rounded-pill-sm);
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 400;
    line-height: 20px;
    letter-spacing: -0.28px;
    transition: all var(--transition);
    display: inline-flex;
    align-items: center;
}

.filter-btn:hover {
    background: var(--color-canvas-soft-2);
    color: var(--color-ink);
    border-color: var(--color-hairline-strong);
}

.filter-btn.active {
    background: var(--color-primary);
    color: var(--color-on-primary);
    border-color: transparent;
}

/* ==========================================================================
   Task List & Task Cards
   ========================================================================== */
.task-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.empty-state {
    text-align: center;
    padding: var(--space-3xl);
    color: var(--color-mute);
    background: var(--color-canvas-soft);
    border-radius: var(--rounded-lg);
    border: 1px dashed var(--color-hairline);
}

.empty-state p {
    font-size: 16px;
    color: var(--color-mute);
}

.task-card {
    background: var(--color-canvas);
    border-radius: var(--rounded-md);
    box-shadow: var(--shadow-level-2);
    padding: var(--space-md) var(--space-lg);
    display: grid;
    grid-template-columns: auto 1fr auto;
    grid-template-rows: auto auto;
    grid-template-areas:
        "badge title actions"
        ". meta meta";
    gap: var(--space-xxs) var(--space-md);
    align-items: center;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    animation: slideIn 0.4s ease-out forwards;
    position: relative;
    overflow: hidden;
}

/* Left accent bar */
.task-card::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--color-hairline-strong);
    transition: background var(--transition);
}

.task-card[data-category="work"]::before     { background: var(--cat-work); }
.task-card[data-category="personal"]::before  { background: var(--cat-personal); }
.task-card[data-category="study"]::before     { background: var(--cat-study); }
.task-card[data-category="health"]::before    { background: var(--cat-health); }
.task-card[data-category="other"]::before     { background: var(--cat-other); }

.task-card:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-level-4);
}

/* Category Badge */
.category-badge {
    grid-area: badge;
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 400;
    line-height: 16px;
    padding: 2px var(--space-xs);
    border-radius: var(--rounded-full);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.category-work     { color: var(--cat-work);     background: rgba(0, 112, 243, 0.08); }
.category-personal { color: var(--cat-personal);  background: rgba(121, 40, 202, 0.08); }
.category-study    { color: var(--cat-study);     background: rgba(255, 0, 128, 0.08); }
.category-health   { color: var(--cat-health);    background: rgba(80, 227, 194, 0.12); }
.category-other    { color: var(--cat-other);     background: rgba(245, 166, 35, 0.08); }

[data-theme="dark"] .category-work     { background: rgba(0, 112, 243, 0.15); }
[data-theme="dark"] .category-personal { background: rgba(121, 40, 202, 0.15); }
[data-theme="dark"] .category-study    { background: rgba(255, 0, 128, 0.15); }
[data-theme="dark"] .category-health   { background: rgba(80, 227, 194, 0.15); }
[data-theme="dark"] .category-other    { background: rgba(245, 166, 35, 0.15); }

/* Task Title */
.task-title {
    grid-area: title;
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 500;
    line-height: 20px;
    letter-spacing: -0.28px;
    margin: 0;
    color: var(--color-ink);
    transition: color var(--transition);
}

/* Task Actions */
.task-actions {
    grid-area: actions;
    display: flex;
    gap: var(--space-xxs);
}

.icon-btn {
    background: transparent;
    border: 1px solid transparent;
    color: var(--color-mute);
    cursor: pointer;
    width: 28px;
    height: 28px;
    border-radius: var(--rounded-sm);
    transition: all var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.icon-btn:hover {
    background: var(--color-canvas-soft);
    border-color: var(--color-hairline);
    color: var(--color-ink);
}

.icon-btn.complete-btn:hover { color: var(--color-success); border-color: rgba(0, 112, 243, 0.2); }
.icon-btn.delete-btn:hover   { color: var(--color-error);   border-color: rgba(238, 0, 0, 0.2); }
.icon-btn.edit-btn:hover     { color: var(--color-violet);  border-color: rgba(121, 40, 202, 0.2); }

/* Task Meta */
.task-meta {
    grid-area: meta;
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    color: var(--color-mute);
    display: flex;
    gap: var(--space-md);
}

/* Completed State */
.task-card[data-status="completed"] {
    opacity: 0.6;
}

.task-card[data-status="completed"] .task-title {
    text-decoration: line-through;
    color: var(--color-mute);
}

.task-card[data-status="completed"]::before {
    background: var(--color-success);
}

/* Edit Mode */
.task-card.editing {
    box-shadow: var(--shadow-level-4);
    border: 1px solid var(--color-link);
}

.edit-input {
    width: 100%;
    padding: 0 var(--space-sm);
    height: 32px;
    background: var(--color-canvas-soft);
    border: 1px solid var(--color-hairline);
    border-radius: var(--rounded-sm);
    color: var(--color-ink);
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 400;
    outline: none;
    transition: border-color var(--transition);
}

.edit-input:focus {
    border-color: var(--color-ink);
    box-shadow: 0 0 0 1px var(--color-ink);
}

.edit-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-xxs);
}

.save-btn {
    display: none !important;
}

.task-card.editing .save-btn {
    display: flex !important;
}

.icon-btn.save-btn:hover {
    color: var(--color-success);
    border-color: rgba(0, 112, 243, 0.2);
}

/* ==========================================================================
   Browser Rendering Pipeline
   ========================================================================== */
.full-width {
    grid-column: 1 / -1;
}

.pipeline-section {
    margin-top: var(--space-lg);
}

.pipeline-section h2 {
    text-align: center;
    margin-bottom: var(--space-xs);
}

.section-desc {
    text-align: center;
    color: var(--color-body);
    margin-bottom: var(--space-xl);
    font-size: 14px;
    line-height: 20px;
}

.pipeline-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-lg);
    padding: var(--space-lg) 0;
    position: relative;
}

.pipeline-card {
    background: var(--color-canvas);
    border: 1px solid var(--color-hairline);
    border-radius: var(--rounded-md);
    box-shadow: var(--shadow-level-2);
    padding: var(--space-lg);
    width: 180px;
    text-align: center;
    position: relative;
    transition: all var(--transition);
    z-index: 2;
}

.pipeline-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-level-4);
    border-color: var(--color-hairline-strong);
}

.pipeline-icon {
    font-size: 1.75rem;
    margin-bottom: var(--space-xs);
    display: block;
}

.pipeline-title {
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 600;
    line-height: 20px;
    letter-spacing: -0.28px;
    margin-bottom: var(--space-xxs);
    color: var(--color-ink);
}

.pipeline-desc {
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    color: var(--color-mute);
}

/* Pipeline Desktop Grid */
@media (min-width: 1024px) {
    .pipeline-card:not(:last-child)::after {
        content: '→';
        position: absolute;
        right: -22px;
        top: 50%;
        transform: translateY(-50%);
        font-size: 1.2rem;
        color: var(--color-mute);
        font-weight: 400;
    }

    .pipeline-card[data-step="7"]::after { content: none; }

    .pipeline-container {
        display: grid;
        grid-template-columns: repeat(5, 1fr);
        grid-template-rows: auto auto;
        gap: var(--space-xl);
        justify-items: center;
    }

    .pipeline-card[data-step="1"] { grid-column: 1; grid-row: 1; }
    .pipeline-card[data-step="2"] { grid-column: 2; grid-row: 1; }
    .pipeline-card[data-step="3"] { grid-column: 3; grid-row: 1; }
    .pipeline-card[data-step="4"] { grid-column: 4; grid-row: 1; }
    .pipeline-card[data-step="5"] { grid-column: 3; grid-row: 2; }
    .pipeline-card[data-step="6"] { grid-column: 4; grid-row: 2; }
    .pipeline-card[data-step="7"] { grid-column: 5; grid-row: 1 / span 2; align-self: center; }

    .pipeline-card[data-step="4"]::after {
        content: '↘';
        right: -22px;
        top: 80%;
    }

    .pipeline-card[data-step="6"]::after {
        content: '↗';
        position: absolute;
        right: -22px;
        top: 20%;
        font-size: 1.2rem;
        color: var(--color-mute);
    }
}

/* ==========================================================================
   Footer
   ========================================================================== */
.app-footer {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-3xl) var(--space-lg);
    color: var(--color-mute);
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 400;
    line-height: 16px;
    border-top: 1px solid var(--color-hairline);
    margin-top: var(--space-xl);
    transition: border-color 0.3s ease, color 0.3s ease;
}

.footer-desc {
    font-size: 12px;
}

.footer-meta {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xxs);
}

.creator {
    font-size: 13px;
    color: var(--color-body);
}

.text-bold {
    font-weight: 600;
}

.footer-links {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.footer-link {
    color: var(--color-mute);
    text-decoration: none;
    transition: color var(--transition);
}

.footer-link:hover {
    color: var(--color-link);
}

.link-divider {
    color: var(--color-hairline-strong);
    font-size: 10px;
}

/* ==========================================================================
   Toast Notifications (ex-toast from DESIGN.md)
   ========================================================================== */
.toast-msg {
    background: var(--color-primary);
    color: var(--color-on-primary);
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--rounded-md);
    margin-bottom: var(--space-md);
    text-align: center;
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 500;
    line-height: 20px;
    box-shadow: var(--shadow-level-4);
    animation: fadeIn 0.3s ease-out;
    position: relative;
    overflow: hidden;
}

.toast-msg::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    height: 2px;
    width: 100%;
    background: linear-gradient(
        90deg,
        var(--grad-develop-start),
        var(--grad-develop-end),
        var(--grad-preview-start),
        var(--grad-preview-end)
    );
    animation: shrinkBar 2s linear forwards;
}

.toast-decor {
    display: none;
}

/* ==========================================================================
   Animations
   ========================================================================== */
@keyframes slideIn {
    from { opacity: 0; transform: translateX(20px); }
    to   { opacity: 1; transform: translateX(0); }
}

@keyframes fadeOut {
    to { opacity: 0; transform: scale(0.97); }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-4px); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes gradientShift {
    0%   { background-position: 0% 50%; }
    50%  { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

@keyframes shrinkBar {
    from { transform: scaleX(1); transform-origin: left; }
    to   { transform: scaleX(0); transform-origin: left; }
}

.item-removing {
    animation: fadeOut 0.3s ease-out forwards;
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */
@media (max-width: 992px) {
    .form-row {
        flex-direction: column;
    }

    .btn-primary {
        width: 100%;
    }
}

@media (max-width: 768px) {
    .container {
        padding: var(--space-md);
    }

    .stats {
        grid-template-columns: 1fr;
        gap: var(--space-xs);
    }

    .stat-box {
        flex-direction: row;
        justify-content: space-between;
        padding: var(--space-md);
    }

    .controls-bar {
        flex-direction: column;
        align-items: stretch;
    }

    .filters {
        justify-content: center;
    }

    .search-box {
        min-width: 100%;
    }

    h1 {
        font-size: 32px;
        line-height: 40px;
        letter-spacing: -1.28px;
    }
}

@media (max-width: 480px) {
    .task-card {
        grid-template-columns: 1fr;
        grid-template-areas:
            "badge"
            "title"
            "actions"
            "meta";
        gap: var(--space-xs);
        padding: var(--space-md);
    }

    .task-actions {
        justify-content: flex-start;
    }

    .header-container {
        padding: 0 var(--space-md);
    }
}

/* ==========================================================================
   Educational Demo Sections (preserved from original)
   ========================================================================== */
.edu-section {
    position: relative;
    overflow: hidden;
}

.edu-section::before {
    content: 'DOM API Demo';
    position: absolute;
    top: 0;
    right: 0;
    background: var(--color-primary);
    color: var(--color-on-primary);
    font-family: var(--font-mono);
    font-size: 10px;
    padding: 2px var(--space-sm);
    border-bottom-left-radius: var(--rounded-sm);
    text-transform: uppercase;
    font-weight: 400;
    letter-spacing: 0.5px;
}

.edu-desc {
    color: var(--color-body);
    font-size: 14px;
    line-height: 20px;
    margin-bottom: var(--space-md);
}

.demo-box {
    background: var(--color-canvas-soft);
    border-radius: var(--rounded-md);
    padding: var(--space-lg);
    border: 1px solid var(--color-hairline);
}

.demo-input {
    width: 100%;
    margin-bottom: var(--space-lg);
    font-size: 14px;
    text-align: center;
}

.demo-results {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

.result-item {
    background: var(--color-canvas);
    padding: var(--space-md);
    border-radius: var(--rounded-sm);
    text-align: center;
    border: 1px solid var(--color-hairline);
}

.badge {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 10px;
    text-transform: uppercase;
    padding: 2px var(--space-xs);
    border-radius: var(--rounded-full);
    margin-bottom: var(--space-xs);
    font-weight: 400;
    letter-spacing: 0.3px;
}

.prop-badge { background: rgba(0, 112, 243, 0.1); color: var(--color-link); }
.attr-badge { background: rgba(121, 40, 202, 0.1); color: var(--color-violet); }

.result-item code {
    display: block;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--color-mute);
    margin-bottom: var(--space-xs);
}

.output-val {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 400;
    line-height: 20px;
    color: var(--color-ink);
    background: var(--color-canvas-soft);
    padding: var(--space-xs);
    border-radius: var(--rounded-sm);
    word-break: break-word;
    border: 1px solid var(--color-hairline);
}

/* ==========================================================================
   Event Propagation Demo
   ========================================================================== */
.prop-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-lg);
    background: var(--color-canvas-soft);
    padding: var(--space-sm);
    border-radius: var(--rounded-sm);
    border: 1px solid var(--color-hairline);
}

.radio-label {
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: 14px;
    color: var(--color-body);
}

.prop-visual {
    margin-bottom: var(--space-lg);
    display: flex;
    justify-content: center;
}

.prop-box {
    padding: var(--space-lg);
    border-radius: var(--rounded-md);
    border: 1px solid;
    transition: all 0.3s;
    position: relative;
}

.gp-box {
    background: rgba(0, 112, 243, 0.04);
    border-color: rgba(0, 112, 243, 0.2);
}

.p-box {
    background: rgba(80, 227, 194, 0.04);
    border-color: rgba(80, 227, 194, 0.2);
    margin-top: var(--space-md);
}

.c-box {
    background: rgba(121, 40, 202, 0.06);
    border-color: rgba(121, 40, 202, 0.3);
    color: var(--color-ink);
    margin-top: var(--space-md);
    cursor: pointer;
    display: block;
    width: 100%;
    font-weight: 500;
    font-family: var(--font-sans);
    border-radius: var(--rounded-sm);
}

.c-box:hover {
    background: rgba(121, 40, 202, 0.1);
    transform: scale(1.01);
}

.box-label {
    position: absolute;
    top: -9px;
    left: 10px;
    background: var(--color-canvas-soft);
    padding: 0 var(--space-xxs);
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--color-mute);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.console-log {
    background: var(--color-primary);
    border-radius: var(--rounded-md);
    overflow: hidden;
    border: 1px solid var(--color-hairline);
    font-family: var(--font-mono);
}

.log-header {
    background: var(--color-canvas-soft-2);
    color: var(--color-body);
    padding: var(--space-xs) var(--space-md);
    font-family: var(--font-mono);
    font-size: 12px;
    display: flex;
    justify-content: space-between;
    border-bottom: 1px solid var(--color-hairline);
}

.log-header::after {
    content: 'Terminal';
    font-family: var(--font-mono);
}

.log-content {
    padding: var(--space-md);
    height: 150px;
    overflow-y: auto;
    color: var(--color-on-primary);
    font-size: 13px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.log-entry {
    animation: fadeIn 0.3s;
}

.log-time   { color: var(--color-mute); margin-right: var(--space-xs); }
.log-target { color: var(--color-cyan); }
.log-phase  { color: var(--color-highlight-pink); }

/* Propagation Highlights */
.highlight-bubble {
    animation: pulse-bubble 0.5s ease-out;
}

.highlight-capture {
    animation: pulse-capture 0.5s ease-out;
}

@keyframes pulse-bubble {
    0%   { box-shadow: 0 0 0 0 rgba(0, 112, 243, 0.5); }
    70%  { box-shadow: 0 0 0 8px rgba(0, 112, 243, 0); }
    100% { box-shadow: 0 0 0 0 rgba(0, 112, 243, 0); }
}

@keyframes pulse-capture {
    0%   { box-shadow: 0 0 0 0 rgba(121, 40, 202, 0.5); }
    70%  { box-shadow: 0 0 0 8px rgba(121, 40, 202, 0); }
    100% { box-shadow: 0 0 0 0 rgba(121, 40, 202, 0); }
}