/* ═══════════════════════════════════════════════
   FlipCalc — Design System & Styles
   ═══════════════════════════════════════════════ */

/* ── Tokens ── */
:root {
    --font: 'Inter', system-ui, -apple-system, sans-serif;

    /* Dark palette */
    --bg-body:       #0b0f19;
    --bg-panel:      #111827;
    --bg-card:       rgba(30, 41, 59, 0.55);
    --bg-card-hover: rgba(30, 41, 59, 0.75);
    --bg-input:      #1e293b;

    --border:        rgba(148, 163, 184, 0.12);
    --border-focus:  rgba(99, 102, 241, 0.6);

    --text-primary:   #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted:     #64748b;

    --accent:         #6366f1;
    --accent-glow:    rgba(99, 102, 241, 0.25);
    --green:          #22c55e;
    --green-glow:     rgba(34, 197, 94, 0.18);
    --red:            #ef4444;
    --yellow:         #eab308;

    /* Platform brand colors */
    --color-ebay:     #e53238;
    --color-poshmark: #7b2d8e;
    --color-mercari:  #4dc4ff;
    --color-depop:    #ff2300;
    --color-etsy:     #f56400;

    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;

    --shadow-card: 0 4px 24px rgba(0,0,0,0.25), 0 1px 3px rgba(0,0,0,0.15);
    --shadow-glow: 0 0 30px var(--accent-glow);
}

/* ── Reset ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: var(--font);
    background: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

/* subtle grid pattern */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
        radial-gradient(circle at 15% 20%, rgba(99,102,241,0.06) 0%, transparent 50%),
        radial-gradient(circle at 85% 70%, rgba(34,197,94,0.04) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 1;
}

/* ═══════ HEADER ═══════ */
.site-header {
    padding: 28px 0 12px;
    border-bottom: 1px solid var(--border);
}
.site-header .container {
    display: flex;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--accent);
}
.logo-icon { flex-shrink: 0; }
.logo-text {
    font-size: 1.55rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, var(--accent), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.tagline {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-left: auto;
}

/* ═══════ INPUT PANEL ═══════ */
.input-panel {
    margin-top: 40px;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 36px 32px 32px;
    box-shadow: var(--shadow-card);
}
.panel-title {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 28px;
    letter-spacing: -0.3px;
}

/* input grid */
.input-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 28px;
}
.input-group label {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.6px;
    margin-bottom: 8px;
}
.input-wrap {
    position: relative;
    display: flex;
    align-items: center;
}
.input-prefix {
    position: absolute;
    left: 14px;
    color: var(--text-muted);
    font-weight: 600;
    font-size: 1.05rem;
    pointer-events: none;
    z-index: 1;
}
.input-wrap input {
    width: 100%;
    background: var(--bg-input);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px 14px 12px 34px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font);
    transition: border-color 0.2s, box-shadow 0.2s;
    appearance: textfield;
    -moz-appearance: textfield;
}
.input-wrap input::-webkit-inner-spin-button,
.input-wrap input::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
.input-wrap input::placeholder { color: var(--text-muted); font-weight: 400; }
.input-wrap input:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ── Toggles ── */
.toggles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
}
.toggle-group {
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px 16px;
}
.toggle-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}
.toggle-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
}
.toggle-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 6px;
    line-height: 1.4;
}

/* toggle tabs (shipping mode) */
.toggle-tabs {
    display: flex;
    background: var(--bg-body);
    border-radius: 8px;
    padding: 3px;
    margin-top: 10px;
}
.toggle-tab {
    flex: 1;
    padding: 8px 12px;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-family: var(--font);
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.25s;
}
.toggle-tab.active {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 2px 8px var(--accent-glow);
}

/* switch */
.switch {
    position: relative;
    width: 44px;
    height: 24px;
    flex-shrink: 0;
}
.switch input { opacity: 0; width: 0; height: 0; }
.slider {
    position: absolute;
    inset: 0;
    background: var(--bg-body);
    border-radius: 24px;
    cursor: pointer;
    transition: background 0.3s;
    border: 1px solid var(--border);
}
.slider::before {
    content: '';
    position: absolute;
    left: 3px;
    top: 3px;
    width: 16px;
    height: 16px;
    background: var(--text-muted);
    border-radius: 50%;
    transition: transform 0.3s, background 0.3s;
}
.switch input:checked + .slider {
    background: var(--accent);
    border-color: var(--accent);
}
.switch input:checked + .slider::before {
    transform: translateX(20px);
    background: #fff;
}

/* ═══════ RESULTS ═══════ */
.results-section {
    margin-top: 48px;
}
.results-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 4px;
}
.results-subtitle {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-bottom: 24px;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 18px;
}

/* ── Platform Card ── */
.platform-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px 22px 22px;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    transition: transform 0.25s, box-shadow 0.3s, border-color 0.3s;
    position: relative;
    overflow: hidden;
    animation: cardIn 0.45s ease-out both;
}
.platform-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--platform-color);
    border-radius: var(--radius-md) var(--radius-md) 0 0;
}
.platform-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-card);
}

/* winner card */
.platform-card.winner {
    border-color: var(--green);
    box-shadow: 0 0 35px var(--green-glow), var(--shadow-card);
}
.platform-card.winner::before {
    background: var(--green);
    height: 3px;
}

.winner-badge {
    display: none;
    position: absolute;
    top: 12px;
    right: 14px;
    background: var(--green);
    color: #fff;
    font-size: 0.68rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    padding: 3px 10px;
    border-radius: 20px;
}
.platform-card.winner .winner-badge { display: block; }

.card-platform-name {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--platform-color);
}

.card-profit {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 2px;
    line-height: 1.1;
}
.card-profit.negative { color: var(--red); }
.card-profit.positive { color: var(--green); }

.card-margin {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 18px;
    font-weight: 500;
}

/* fee breakdown */
.fee-breakdown {
    display: flex;
    flex-direction: column;
    gap: 6px;
    border-top: 1px solid var(--border);
    padding-top: 14px;
}
.fee-row {
    display: flex;
    justify-content: space-between;
    font-size: 0.78rem;
    color: var(--text-secondary);
}
.fee-row span:last-child {
    font-weight: 600;
    color: var(--text-primary);
}
.fee-row.total {
    border-top: 1px solid var(--border);
    padding-top: 8px;
    margin-top: 4px;
    font-weight: 700;
    color: var(--text-primary);
    font-size: 0.82rem;
}
.fee-row .note {
    font-size: 0.7rem;
    color: var(--text-muted);
    font-style: italic;
}

/* Card entrance animation */
@keyframes cardIn {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.97);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}
.platform-card:nth-child(1) { animation-delay: 0.00s; }
.platform-card:nth-child(2) { animation-delay: 0.06s; }
.platform-card:nth-child(3) { animation-delay: 0.12s; }
.platform-card:nth-child(4) { animation-delay: 0.18s; }
.platform-card:nth-child(5) { animation-delay: 0.24s; }

/* Winner pulse */
@keyframes winnerPulse {
    0%,100% { box-shadow: 0 0 25px var(--green-glow); }
    50% { box-shadow: 0 0 45px var(--green-glow), 0 0 15px rgba(34,197,94,0.10); }
}
.platform-card.winner { animation: winnerPulse 3s ease-in-out infinite; }

/* ═══════ INFO SECTION ═══════ */
.info-section {
    margin-top: 64px;
    text-align: center;
}
.info-section h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 12px;
}
.info-section > p {
    max-width: 640px;
    margin: 0 auto 32px;
    color: var(--text-secondary);
    font-size: 0.95rem;
}
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}
.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 28px 22px;
    text-align: center;
    backdrop-filter: blur(8px);
}
.info-icon { font-size: 2rem; display: block; margin-bottom: 12px; }
.info-card h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 8px;
}
.info-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.55;
}

/* ═══════ FOOTER ═══════ */
.site-footer {
    margin-top: 80px;
    border-top: 1px solid var(--border);
    padding: 24px 0;
    text-align: center;
    font-size: 0.78rem;
    color: var(--text-muted);
}

/* ═══════ RESPONSIVE ═══════ */
@media (max-width: 768px) {
    .input-panel { padding: 24px 18px 20px; }
    .panel-title { font-size: 1.3rem; }
    .input-grid { grid-template-columns: 1fr; }
    .toggles-grid { grid-template-columns: 1fr; }
    .results-grid { grid-template-columns: 1fr 1fr; }
    .tagline { display: none; }
    .card-profit { font-size: 1.6rem; }
}
@media (max-width: 480px) {
    .results-grid { grid-template-columns: 1fr; }
    .site-header .container { justify-content: center; }
}