:root {
    --font-heading: "Sora", "Trebuchet MS", sans-serif;
    --font-body: "Manrope", "Segoe UI", sans-serif;
    --bg-start: #edf4ff;
    --bg-end: #f9fbff;
    --surface: rgba(255, 255, 255, 0.8);
    --surface-strong: rgba(255, 255, 255, 0.94);
    --surface-soft: rgba(233, 241, 255, 0.7);
    --text-primary: #122744;
    --text-muted: #48627f;
    --accent: #0f7aef;
    --accent-strong: #0b66ca;
    --accent-soft: rgba(15, 122, 239, 0.12);
    --border: rgba(16, 54, 92, 0.14);
    --success: #1c8f52;
    --danger: #b83232;
    --radius-lg: 18px;
    --radius-md: 12px;
    --shadow: 0 18px 48px rgba(16, 50, 84, 0.14);
}

:root[data-theme="dark"] {
    --bg-start: #101824;
    --bg-end: #070d15;
    --surface: rgba(13, 25, 39, 0.82);
    --surface-strong: rgba(16, 29, 45, 0.95);
    --surface-soft: rgba(23, 40, 60, 0.85);
    --text-primary: #dce9ff;
    --text-muted: #90a8c4;
    --accent: #52a8ff;
    --accent-strong: #85c2ff;
    --accent-soft: rgba(82, 168, 255, 0.18);
    --border: rgba(132, 174, 214, 0.2);
    --success: #55cb88;
    --danger: #f08b8b;
    --shadow: 0 18px 48px rgba(3, 8, 15, 0.45);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html,
body {
    min-height: 100%;
}

body {
    font-family: var(--font-body);
    color: var(--text-primary);
    background: radial-gradient(circle at 15% 20%, rgba(35, 157, 255, 0.16), transparent 45%),
        radial-gradient(circle at 85% 8%, rgba(9, 110, 212, 0.13), transparent 42%),
        linear-gradient(145deg, var(--bg-start), var(--bg-end));
    line-height: 1.5;
    transition: background-color 0.25s ease, color 0.25s ease;
}

body::before,
body::after {
    content: "";
    position: fixed;
    border-radius: 999px;
    pointer-events: none;
    filter: blur(2px);
}

body::before {
    width: 320px;
    height: 320px;
    top: -110px;
    right: -90px;
    background: rgba(47, 162, 255, 0.2);
}

body::after {
    width: 250px;
    height: 250px;
    left: -80px;
    bottom: -100px;
    background: rgba(76, 114, 255, 0.18);
}

.app-shell {
    width: min(1120px, 92vw);
    margin: 0 auto;
    padding: 1.2rem 0 1.8rem;
    position: relative;
    z-index: 1;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.7rem;
    text-decoration: none;
    color: inherit;
}

.logo {
    width: 50px;
    height: 40px;
    border-radius: 14px;
    box-shadow: var(--shadow);
}

.brand-text {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.02em;
}

.theme-toggle {
    border: 1px solid var(--border);
    background: var(--surface-strong);
    color: inherit;
    border-radius: 999px;
    padding: 0.58rem 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    cursor: pointer;
    font-weight: 600;
}

.theme-toggle__dot {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    box-shadow: 0 0 0 4px var(--accent-soft);
}

.main-layout {
    margin-top: 1rem;
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    gap: 1rem;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.35rem;
    box-shadow: var(--shadow);
    backdrop-filter: blur(12px);
    animation: rise 0.5s ease both;
}

.main-layout .card:nth-child(2) {
    animation-delay: 0.08s;
}

.result-panel {
    margin-top: 1rem;
    background: var(--surface-strong);
    animation-delay: 0.14s;
}

.eyebrow {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--accent-strong);
    font-weight: 700;
}

.hero-title {
    margin-top: 0.5rem;
    font-family: var(--font-heading);
    font-size: clamp(1.6rem, 2.4vw, 2.15rem);
    line-height: 1.18;
}

.hero-copy {
    margin-top: 0.8rem;
    color: var(--text-muted);
    max-width: 38ch;
}

.hero-points {
    margin-top: 1rem;
    display: grid;
    gap: 0.55rem;
    list-style: none;
}

.hero-points li {
    position: relative;
    padding-left: 1.05rem;
}

.hero-points li::before {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent);
    position: absolute;
    left: 0;
    top: 0.62rem;
}

.metrics {
    margin-top: 1.1rem;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.55rem;
}

.metrics article {
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--surface-soft);
    padding: 0.72rem;
}

.metric-value {
    font-family: var(--font-heading);
    font-weight: 700;
}

.metric-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.planner-panel h2,
.result-panel h2 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    margin-bottom: 0.85rem;
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.8rem 0.95rem;
}

.field-group {
    display: flex;
    flex-direction: column;
    gap: 0.38rem;
}

.field-group--wide {
    grid-column: 1 / -1;
}

label {
    font-size: 0.86rem;
    font-weight: 700;
}

input,
select,
textarea {
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 0.67rem 0.72rem;
    background: var(--surface-strong);
    color: inherit;
    font: inherit;
}

textarea {
    resize: vertical;
    min-height: 90px;
}

input:focus,
select:focus,
textarea:focus,
button:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.options-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1rem;
}

.checkbox {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
}

.checkbox input {
    width: auto;
    accent-color: var(--accent);
}

.study-summary {
    margin-top: 0.8rem;
    padding: 0.65rem 0.8rem;
    border-radius: 10px;
    background: var(--surface-soft);
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

.form-actions {
    margin-top: 1rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.primary-btn,
.secondary-btn,
.ghost-btn {
    border-radius: 10px;
    border: 1px solid transparent;
    padding: 0.62rem 0.95rem;
    font: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.16s ease, opacity 0.16s ease, border-color 0.16s ease;
}

.primary-btn {
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    color: #ffffff;
    box-shadow: 0 8px 20px rgba(0, 90, 190, 0.28);
}

.secondary-btn,
.ghost-btn {
    border-color: var(--border);
    background: var(--surface-strong);
    color: inherit;
}

.primary-btn:hover,
.secondary-btn:hover,
.ghost-btn:hover {
    transform: translateY(-1px);
}

.primary-btn:disabled,
.secondary-btn:disabled,
.ghost-btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    transform: none;
}

.loading {
    margin-top: 0.8rem;
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    color: var(--text-muted);
    font-weight: 600;
}

.loading-spinner {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 2px solid var(--accent-soft);
    border-top-color: var(--accent);
    animation: spin 0.8s linear infinite;
}

.status-message {
    margin-top: 0.65rem;
    min-height: 1.2rem;
    font-size: 0.9rem;
}

.status-message[data-status="success"] {
    color: var(--success);
}

.status-message[data-status="error"] {
    color: var(--danger);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.result-actions {
    display: inline-flex;
    gap: 0.5rem;
}

.empty-state {
    margin-top: 0.35rem;
    color: var(--text-muted);
}

.plan-result {
    margin-top: 0.85rem;
    background: var(--surface-soft);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    min-height: 210px;
    padding: 0.95rem;
    white-space: pre-wrap;
    word-wrap: break-word;
    font-family: "SF Mono", "Consolas", monospace;
    font-size: 0.95rem;
}

.footer {
    padding: 0.45rem 1rem 1.1rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.88rem;
}

.hidden {
    display: none !important;
}

@media (max-width: 980px) {
    .main-layout {
        grid-template-columns: 1fr;
    }

    .hero-copy {
        max-width: none;
    }
}

@media (max-width: 720px) {
    .app-shell {
        width: min(1120px, 94vw);
    }

    .topbar {
        flex-wrap: wrap;
    }

    .form-grid {
        grid-template-columns: 1fr;
    }

    .metrics {
        grid-template-columns: 1fr;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation: none !important;
        transition: none !important;
    }
}

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

@keyframes rise {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}