:root {
    --bg-color: #0f1117;
    --surface-color: #1a1d24;
    --surface-hover: #22262f;
    --border-color: #2e323a;
    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --gold-color: #f5b942;
    --gold-hover: #e0a52d;
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: all 0.2s ease-in-out;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

.hidden { display: none !important; }

button { font-family: inherit; cursor: pointer; }
input { font-family: inherit; }

.btn {
    border: 1px solid var(--border-color);
    background: var(--surface-color);
    color: var(--text-primary);
    padding: 0.65rem 1.2rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
}
.btn:hover { background: var(--surface-hover); }
.btn.primary { background: var(--accent-color); border-color: var(--accent-color); }
.btn.primary:hover { background: var(--accent-hover); }
.btn.ghost { background: transparent; }
.btn.small { padding: 0.4rem 0.8rem; font-size: 0.85rem; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ===================== LOGIN ===================== */
#login-screen {
    min-height: 100vh;
    display: flex; align-items: center; justify-content: center;
    padding: 1.5rem;
}
.login-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    max-width: 380px;
    width: 100%;
    text-align: center;
}
.brand { font-size: 1.8rem; margin-bottom: 0.4rem; }
.brand-sub { color: var(--text-secondary); margin-bottom: 1.5rem; }
.profile-picker { display: flex; flex-direction: column; gap: 0.75rem; }
.profile-btn {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    color: var(--text-primary);
    font-size: 1.05rem;
    font-weight: 600;
    transition: var(--transition);
}
.profile-btn:hover { border-color: var(--accent-color); background: var(--surface-hover); }
.pin-step { margin-top: 1rem; }
.pin-label { color: var(--text-secondary); margin-bottom: 0.75rem; }
.pin-input {
    width: 100%;
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    padding: 0.8rem;
    font-size: 1.4rem;
    text-align: center;
    letter-spacing: 0.3em;
    margin-bottom: 1rem;
}
.pin-actions { display: flex; gap: 0.5rem; }
.pin-actions .btn { flex: 1; }
.pin-error { color: var(--danger-color); margin-top: 0.75rem; font-size: 0.9rem; }

/* ===================== TOPBAR ===================== */
.topbar {
    display: flex; align-items: center; justify-content: space-between;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap; gap: 0.75rem;
}
.brand-mini { font-weight: 700; font-size: 1.05rem; }
.topbar-right { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.stat-pill {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 999px;
    padding: 0.35rem 0.8rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
    display: flex; align-items: center; gap: 0.4rem;
}
.stat-icon { font-size: 0.95rem; }

/* ===================== VIEWS ===================== */
.view { max-width: 960px; margin: 0 auto; padding: 2rem 1.5rem 4rem; }
.view-title { font-size: 1.6rem; font-weight: 700; margin-bottom: 0.4rem; }
.view-sub { color: var(--text-secondary); margin-bottom: 2rem; }

/* Subject picker */
.subject-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; }
.subject-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-align: left;
    color: var(--text-primary);
    transition: var(--transition);
    display: flex; flex-direction: column; gap: 0.5rem;
}
.subject-card:not(:disabled):hover { border-color: var(--accent-color); transform: translateY(-2px); }
.subject-card:disabled { opacity: 0.5; cursor: not-allowed; }
.subject-icon { font-size: 2rem; }
.subject-title { font-weight: 700; font-size: 1.1rem; }
.subject-desc { color: var(--text-secondary); font-size: 0.9rem; }
.subject-badge {
    align-self: flex-start;
    font-size: 0.75rem;
    padding: 0.15rem 0.55rem;
    border-radius: 999px;
    background: var(--accent-color);
    color: #fff;
}
.subject-badge.soon { background: var(--border-color); color: var(--text-secondary); }

/* Roadmap header */
.roadmap-header { margin-bottom: 2rem; }
.roadmap-progress-wrap { display: flex; align-items: center; gap: 0.75rem; margin-top: 0.75rem; }
.roadmap-progress-bg { flex: 1; height: 8px; background: var(--surface-color); border-radius: 999px; overflow: hidden; }
.roadmap-progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent-color), var(--gold-color)); transition: width 0.4s ease; }
.roadmap-progress-text { font-family: 'JetBrains Mono', monospace; color: var(--text-secondary); font-size: 0.85rem; white-space: nowrap; }

/* ===================== ROADMAP PATH (signature element) ===================== */
.path-container { position: relative; padding: 1rem 0 1rem 2rem; }
.path-phase { position: relative; margin-bottom: 2.5rem; }
.path-phase::before {
    content: '';
    position: absolute;
    left: -1.5rem; top: 2.5rem; bottom: -2.5rem;
    width: 2px;
    background: var(--border-color);
}
.path-phase:last-child::before { display: none; }
.path-phase.complete::before { background: var(--success-color); }

.phase-head { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1rem; }
.phase-node {
    width: 2.75rem; height: 2.75rem; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 1.1rem;
    background: var(--surface-color); border: 2px solid var(--border-color);
    flex-shrink: 0;
    margin-left: -2.85rem;
}
.path-phase.complete .phase-node { background: var(--success-color); border-color: var(--success-color); }
.path-phase.locked .phase-node { opacity: 0.5; }
.phase-title { font-weight: 700; font-size: 1.05rem; }
.phase-goal { color: var(--text-secondary); font-size: 0.85rem; }
.phase-count { margin-left: auto; font-family: 'JetBrains Mono', monospace; font-size: 0.8rem; color: var(--text-secondary); white-space: nowrap; }

.phase-tasks { display: flex; flex-direction: column; gap: 0.5rem; margin-left: 0.5rem; }
.task-node {
    display: flex; align-items: center; gap: 0.75rem;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.8rem 1rem;
    transition: var(--transition);
    text-align: left;
    color: var(--text-primary);
    width: 100%;
}
.task-node:not(:disabled):hover { border-color: var(--accent-color); background: var(--surface-hover); }
.task-node:disabled { opacity: 0.45; cursor: not-allowed; }
.task-check {
    width: 1.6rem; height: 1.6rem; border-radius: 50%;
    border: 2px solid var(--border-color);
    display: flex; align-items: center; justify-content: center;
    font-size: 0.85rem; flex-shrink: 0;
}
.task-node.done .task-check { background: var(--success-color); border-color: var(--success-color); }
.task-type-tag {
    font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.04em;
    padding: 0.1rem 0.45rem; border-radius: 4px;
    background: var(--bg-color); color: var(--text-secondary);
    flex-shrink: 0;
}
.task-type-tag.visual { background: rgba(245, 185, 66, 0.15); color: var(--gold-color); }
.task-title-text { flex: 1; font-size: 0.95rem; }

.locked-hint { color: var(--text-secondary); font-size: 0.85rem; padding: 0.5rem 0 0 0.5rem; }

/* ===================== TASK DRAWER ===================== */
.drawer { position: fixed; inset: 0; z-index: 50; }
.drawer-backdrop { position: absolute; inset: 0; background: rgba(0,0,0,0.6); }
.drawer-panel {
    position: absolute; top: 0; right: 0; bottom: 0;
    width: min(520px, 100%);
    background: var(--surface-color);
    border-left: 1px solid var(--border-color);
    padding: 2rem 1.75rem;
    overflow-y: auto;
}
.drawer-close {
    position: absolute; top: 1rem; right: 1rem;
    background: transparent; border: none; color: var(--text-secondary);
    font-size: 1.2rem; width: 2rem; height: 2rem; border-radius: 50%;
}
.drawer-close:hover { background: var(--surface-hover); color: var(--text-primary); }
.drawer-title { font-size: 1.3rem; font-weight: 700; margin: 0 2rem 0.5rem 0; }
.drawer-prompt { color: var(--text-secondary); margin-bottom: 1.25rem; }

.answer-row { display: flex; gap: 0.5rem; margin-bottom: 0.75rem; }
.answer-input {
    flex: 1; background: var(--bg-color); border: 1px solid var(--border-color);
    color: var(--text-primary); border-radius: var(--radius-sm); padding: 0.7rem 0.9rem;
    font-family: 'JetBrains Mono', monospace;
}
.answer-feedback { font-size: 0.9rem; margin-top: 0.5rem; }
.answer-feedback.correct { color: var(--success-color); }
.answer-feedback.wrong { color: var(--danger-color); }

.checklist-confirm { display: flex; align-items: flex-start; gap: 0.6rem; margin-bottom: 1.25rem; }

.code-editor {
    width: 100%; min-height: 160px;
    background: var(--bg-color); color: var(--text-primary);
    border: 1px solid var(--border-color); border-radius: var(--radius-sm);
    font-family: 'JetBrains Mono', monospace; font-size: 0.9rem; padding: 0.9rem;
    resize: vertical; margin-bottom: 0.75rem;
}
.visual-canvas-wrap {
    background: #0b0d12; border: 1px solid var(--border-color); border-radius: var(--radius-sm);
    margin-bottom: 0.75rem; display: flex; align-items: center; justify-content: center; min-height: 260px;
    overflow: auto;
}
.visual-error { color: var(--danger-color); font-size: 0.85rem; margin-bottom: 0.75rem; white-space: pre-wrap; }
.drawer-actions { display: flex; gap: 0.6rem; margin-top: 1rem; }

/* ===================== TOAST / CONFETTI ===================== */
.toast {
    position: fixed; bottom: 1.5rem; left: 50%; transform: translateX(-50%) translateY(1rem);
    background: var(--surface-color); border: 1px solid var(--gold-color);
    color: var(--text-primary); padding: 0.9rem 1.4rem; border-radius: var(--radius-md);
    font-weight: 600; opacity: 0; transition: var(--transition);
    z-index: 100; max-width: 90vw; text-align: center;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
#confetti-canvas { position: fixed; inset: 0; pointer-events: none; z-index: 99; }

/* ===================== MENTOR VIEW ===================== */
.mentor-body { display: flex; flex-direction: column; gap: 1.5rem; }
.mentor-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 1rem; }
.mentor-stat {
    background: var(--surface-color); border: 1px solid var(--border-color);
    border-radius: var(--radius-md); padding: 1.25rem;
}
.mentor-stat-label { color: var(--text-secondary); font-size: 0.85rem; margin-bottom: 0.35rem; }
.mentor-stat-value { font-size: 1.7rem; font-weight: 700; font-family: 'JetBrains Mono', monospace; }
.mentor-section {
    background: var(--surface-color); border: 1px solid var(--border-color);
    border-radius: var(--radius-md); padding: 1.5rem;
}
.mentor-section h3 { font-size: 1.05rem; margin-bottom: 1rem; }
.bar-chart { display: flex; align-items: flex-end; gap: 0.6rem; height: 120px; }
.bar-col { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 0.4rem; }
.bar-fill { width: 100%; background: linear-gradient(180deg, var(--accent-color), var(--accent-hover)); border-radius: 4px 4px 0 0; min-height: 2px; }
.bar-label { font-size: 0.7rem; color: var(--text-secondary); }
.activity-row { display: flex; justify-content: space-between; gap: 1rem; padding: 0.6rem 0; border-bottom: 1px solid var(--border-color); font-size: 0.9rem; }
.activity-row:last-child { border-bottom: none; }
.activity-meta { color: var(--text-secondary); font-size: 0.8rem; }
.badge-row { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.badge-chip { background: rgba(245, 185, 66, 0.12); border: 1px solid var(--gold-color); color: var(--gold-color); padding: 0.35rem 0.75rem; border-radius: 999px; font-size: 0.85rem; }
.empty-state { color: var(--text-secondary); text-align: center; padding: 2rem; }

@media (max-width: 640px) {
    .path-container { padding-left: 1.25rem; }
    .phase-node { margin-left: -2.1rem; width: 2.2rem; height: 2.2rem; font-size: 0.95rem; }
    .path-phase::before { left: -1rem; }
}